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1.  Rubella epidemic caused by genotype 1E rubella viruses in Beijing, China, in 2007–2011 
Virology Journal  2013;10:122.
Background
A series of different rubella vaccination strategies were implemented to control rubella and prevent congenital rubella virus infection in Beijing, China. The rubella vaccine was available in 1995 in Beijing, and was introduced into the Beijing immunization program (vaccine recipients at their own expense vaccination) in 2000, and was introduced into the National Expanded Program on Immunization (vaccine recipients free vaccination) in 2006. Rubella virological surveillance started in Beijing in 2007.
Results
The reported rubella incidence rate has decreased dramatically due to the introduction of the vaccine in Beijing since 1995. However, rubella epidemics occurred regardless in 2001 and 2007. The incidence rate among the floating population has gradually increased since 2002, reaching 2 or more times that in the permanent resident population. The peak age of rubella cases gradually changed from <15 years of age to adults after 2005. Phylogenetic analysis was performed and a phylogenetic tree was constructed based on the World Health Organization standard sequence window for rubella virus isolates. All Beijing rubella virus isolates belong to genotype 1E/cluster1 and were clustered interspersed with viruses from other provinces in China. The effective number of infections indicated by a Bayesian skyline plot remained constant from 2007 to 2011.
Conclusions
The proportion of rubella cases among the floating population has increased significantly in Beijing since 2002, and the disease burden gradually shifted to the older age group (15- to 39-year olds), which has become a major group with rubella infection since 2006. Genotype 1E rubella virus continuously caused a rubella epidemic in Beijing in 2007–2011 and was the predominant virus, and all Beijing genotype 1E viruses belong to cluster 1, which is also widely circulated throughout the country.
doi:10.1186/1743-422X-10-122
PMCID: PMC3660283  PMID: 23596982
Rubella epidemics; Rubella virus; Genotype 1E, Beijing
2.  Rubella Epidemics and Genotypic Distribution of the Rubella Virus in Shandong Province, China, in 1999–2010 
PLoS ONE  2012;7(7):e42013.
Background
The rubella vaccine was introduced into the immunization program in 1995 in the Shandong province, China. A series of different rubella vaccination strategies were implemented at different stages of measles control in Shandong province.
Methodology/Principal Findings
The average reported incidence rate of rubella cases remained at a low level in Shandong province after 1999. However, rubella epidemics occurred repeatedly in 2001/2002, 2006, and 2008/2009. The age of the onset of rubella cases gradually increased during 1999–2010, which showed that most cases were found among the 10 years old in 1999 and among the 17 years old in 2010. Phylogenetic analysis was performed and a phylogenetic tree was constructed based on the World Health Organization standard sequence window for rubella virus isolates. All rubella viruses isolated in Shandong province were divided into 4 genotypes: 1E, 1F, 2A, and 2B. Genotype 1E viruses accounted for the majority (79%) of all these viruses. The similarity of nucleotide and amino acid sequences among genotype 1E viruses was 98.2–100% and 99.1–100%, respectively. All Shandong genotype 1E strains, differed from international genotype 1E strains, belonged to cluster 1 and interdigitated with the viruses from other provinces in mainland China. The effective number of infections indicated by a Bayesian skyline plot remained constant from 2001 to 2009.
Conclusions/Significance
The gradual shift of disease burden to an older age group occurred after a rubella-containing vaccine was introduced into the childhood immunization schedule in 1995 in Shandong province. Four genotypes, including 1E, 1F, 2A, and 2B, were found in Shandong province during 2000–2009. Genotype 1E, rather than genotype 1F, became the predominant genotype circulating in Shandong province from 2001. All Shandong genotype 1E viruses belong to the genotype 1E/cluster 1; they have constantly circulated, and co-evolved and co-circulated, with those from other provinces.
doi:10.1371/journal.pone.0042013
PMCID: PMC3404038  PMID: 22911874
3.  Rubella Virus Genotypes in the People's Republic of China between 1979 and 2007: a Shift in Endemic Viruses during the 2001 Rubella Epidemic▿ † 
Journal of Clinical Microbiology  2010;48(5):1775-1781.
The incidence of rubella cases in China from 1991 to 2007 was reviewed, and the nucleotide sequences from 123 rubella viruses collected during 1999 to 2007 and 4 viral sequences previously reported from 1979 to 1984 were phylogenetically analyzed. Rubella vaccination was not included in national immunization programs in China before 2007. Changes in endemic viruses were compared with incidences of rubella epidemics. The results showed that rubella epidemics occur approximately every 6 to 8 years (1993/1994, 2001, and 2007), and a shift of disease burden to susceptible young adults was observed. The Chinese rubella virus sequences were categorized into 5 of the 13 rubella virus genotypes, 1a, 1E, 1F, 2A, and 2B; cocirculations of these different genotypes were found in China. In Anhui province, a shift in the predominant genotype from 1F and 2B to 1E coincided with the 2001 rubella epidemic. This shift may have occurred throughout China during 2001 to 2007. This study investigated the genotype distribution of rubella viruses in China over a 28-year period to establish an important genetic baseline in China during its prevaccination era.
doi:10.1128/JCM.02055-09
PMCID: PMC2863877  PMID: 20351211
4.  Imported Genotype 2B Rubella Virus Caused the 2012 Outbreak in Anqing City, China 
PLoS ONE  2015;10(9):e0139173.
A rubella outbreak occurred in Anqing city of Anhui province, China, from February to July of 2012, and a total of 241 clinically diagnosed or lab-confirmed patients were reported. The highest number of rubella cases during this outbreak was recorded in teenagers between 10 and 19 years of age who had not previously received the rubella vaccine. Genotyping results indicated that the genotype 2B rubella virus (RV) was responsible for the outbreak. However, a phylogenetic analysis showed that the genotype 2B RVs isolated in Anqing City were not related to 2B RVs found in other cities of Anhui province and in other provinces of China, thus providing evidence for importation. After importation, the transmission of Anqing RVs was interrupted owing to an effective immunization campaign against rubella, suggesting the timeliness and effectiveness of contingency vaccination. Strengthening rubella surveillance, including the integration of epidemiologic information and laboratory data, is a vital strategy for rubella control and elimination. In addition, except for routine immunization, targeted supplementary immunization activities aimed at susceptible groups according to sero-epidemiological surveillance data also play a key role in stopping the continuous transmission of rubella viruses and in preventing further congenital rubella syndrome cases.
doi:10.1371/journal.pone.0139173
PMCID: PMC4581689  PMID: 26402467
5.  Phylogenetic Analysis of Rubella Viruses Identified in Uganda, 2003–2012 
Journal of medical virology  2014;86(12):2107-2113.
Molecular data on rubella viruses are limited in Uganda despite the importance of congenital rubella syndrome (CRS). Routine rubella vaccination, while not administered currently in Uganda, is expected to begin by 2015. The World Health Organization recommends that countries without rubella vaccination programs assess the burden of rubella and CRS before starting a routine vaccination program. Uganda is already involved in integrated case-based surveillance, including laboratory testing to confirm measles and rubella, but molecular epidemiologic aspects of rubella circulation have so far not been documented in Uganda. Twenty throat swab or oral fluid samples collected from 12 districts during routine rash and fever surveillance between 2003 and 2012 were identified as rubella virus RNA positive and PCR products encompassing the region used for genotyping were sequenced. Phylogenetic analysis of the 20 sequences identified 19 genotype 1G viruses and 1 genotype 1E virus. Genotype-specific trees showed that the Uganda viruses belonged to specific clusters for both genotypes 1G and 1E and grouped with similar sequences from neighboring countries. Genotype 1G was predominant in Uganda. More epidemiological and molecular epidemiological data are required to determine if genotype 1E is also endemic in Uganda. The information obtained in this study will assist the immunization program in monitoring changes in circulating genotypes.
doi:10.1002/jmv.23935
PMCID: PMC4269980  PMID: 24700073
genotype; molecular characterization; sequences; rubella epidemiology
6.  Trends of rubella incidence during a 5-year period of case based surveillance in Zimbabwe 
BMC Public Health  2015;15:294.
Background
Rubella is a disease of public health significance owing to its adverse effects during pregnancy and on pregnancy outcomes. Women who contract rubella virus during pregnancy may experience complications such as foetal death or give birth to babies born with congenital rubella syndrome. Vaccination against rubella is the most effective and economical approach to control the disease, and to avoid the long term effects and high costs of care for children with congenital rubella syndrome as well as to prevent death from complications. Zimbabwe commenced rubella surveillance in 1999, despite lacking a rubella vaccine in the national Expanded Programme on Immunization, as per the World Health Organization recommendation to establish a surveillance system to estimate the disease burden before introduction of a rubella vaccine. The purpose of this analysis is to describe the disease trends and population demographics of rubella cases that were identified through the Zimbabwe national measles and rubella case-based surveillance system during a 5-year period between 2007 and 2011.
Methods
Data from the Zimbabwe National Measles Laboratory for the 5-year study period were analysed for age, sex, district of origin, seasonality, and rubella IgM serostatus.
Results
A total of 3428 serum samples from cases of suspected measles in all administrative districts of the country were received by the laboratory during this period. Cases included 51% males and 49% females. Of these, 2999 were tested for measles IgM of which 697 (23.2%) were positive. Of the 2302 measles IgM-negative samples, 865 (37.6%) were rubella IgM-positive. Ninety-eight percent of confirmed rubella cases were children younger than 15 years of age. Most infections occurred during the dry season.
Conclusions
The national case-based surveillance revealed the disease burden and trends of rubella in Zimbabwe. These data add to the evidence for introducing rubella-containing vaccine into the national immunization programme.
Electronic supplementary material
The online version of this article (doi:10.1186/s12889-015-1642-4) contains supplementary material, which is available to authorized users.
doi:10.1186/s12889-015-1642-4
PMCID: PMC4391168  PMID: 25885586
Rubella; Zimbabwe; Seroprevalence; Incidence; Surveillance; Trends
7.  Pregnant Women in and Around Dhaka City: Are Their Children at Risk of Developing Congenital Rubella Syndrome? 
Indian Journal of Microbiology  2011;50(4):443-448.
Rubella Virus (RUBV) is a common cause of childhood rash and fever in non-immunized populations, and its public health importance relates to teratogenic effects of primary rubella infection in women with early pregnancy. Infection of the fetus may lead to congenital rubella syndrome (CRS). This work aimed to assess the degree of risk associated in acquiring rubella virus infection by the women during pregnancy and developing CRS among their children in Bangladesh. The study population (n = 275) included pregnant mothers (15–38 years) from various socioeconomic backgrounds attending a women health care based hospital. All subjects were personally interviewed, clinically examined and a standardized questionnaire was filled up for each of them. From each participant 3 ml blood was taken and serum was separated. Commercially available ELISA kit was used for the qualitative and quantitative determination of IgM and IgG class antibodies against RUBV in collected serum samples. 209 women were found to contain detectable level of antiRUBV IgG antibodies, but did not possess IgM antibodies against rubella. Only 9% participants were vaccinated previously against rubella virus among the whole antenatal population studied. Ninety-two percent of these vaccinated pregnant women contained serum anti-rubella IgG antibody which was significantly (P = 0.05) higher than that of the nonvaccinated study population (75%). Pregnant women from lower middle and poor socioeconomic class had significantly (P = 0.05) more intra uterine growth retardation (IUGR) of fetus than the upper middle class. 20% of the women of child bearing age examined in this work were not yet exposed to RUBV and at risk of acquiring this virus during pregnancy and subsequently transmitting the virus to the fetus. Our work demonstrates rubella attack rate among antenatal population in Bangladesh as 14.5 in 1000 during pregnancy. A proper and reliable vaccination policy against rubella virus is not yet adopted at the national level in many developing countries including Bangladesh. This work identifies the requirement of detailed study for the identification of intrauterine rubella infection and its related influence on perinatal morbidity and mortality. Thorough epidemiological studies are also considered necessary prior to the development and acceptance of national immunization program against rubella virus in Bangladesh.
doi:10.1007/s12088-011-0094-5
PMCID: PMC3209850  PMID: 22282613
Rubella virus; Pregnancy; Congenital rubella syndrome
8.  Sero-positivity rate of rubella and associated factors among pregnant women attending antenatal care in Mwanza, Tanzania 
Background
Sero-positivity rates of the rubella virus among pregnant women vary widely throughout the world. In Tanzania, rubella vaccination is not included in the national immunization schedule and there is therefore no antenatal screening for this viral disease. So far, there are no reports on the sero-prevalence of rubella among pregnant women in Tanzania. As a result, this study was undertaken to establish the sero-positivity rate of rubella and rubella risk factors among pregnant women attending antenatal care clinics in Mwanza, Tanzania.
Methods
From November 2012 to May 2013 a total of 350 pregnant women were enrolled and their serum samples collected and analyzed using the AXSYM anti-rubella virus IgG/IgM-MEIA test. Demographic and clinical data were collected using a standardized data collection tool. Data analysis was done using STATA version 12.
Results
Of 342 pregnant women tested for rubella antibodies, 317 (92.6%) were positive for anti-rubella IgG while only 1 (0.3%) was positive for IgM. Higher sero-positivity rates were found in the age group of 25–44 years. Furthermore, it was observed that with each year increase in age, the risk of contracting rubella increases by 12% (OR = 1.12, 95% CI: 1.02-1.22, P = 0.019). Women involved in farming and business women were at a higher risk of contracting rubella infection compared to formally employed women (OR: 4.9, P = 0.011; OR 7.1, p = 0.003 respectively). In univariate analysis, the risk of contracting rubella virus infection was found to increase with gestational age with a statistical significance.
Conclusions
Sero-positivity rates of rubella are high in Mwanza and are significantly associated with an increase in age and being a farmer or a business woman. Screening of rubella and immunization of women at risk are highly recommended in this area with a high non-immune rate against rubella virus.
doi:10.1186/1471-2393-14-95
PMCID: PMC3975942  PMID: 24589180
Prevalence; Rubella; Pregnancy; Mwanza; Tanzania
9.  Rubella antibody levels in school-aged children in Newfoundland: Implications for a two-dose rubella vaccination strategy 
OBJECTIVE:
To determine the prevailing levels of rubella immunity among school-aged children who received a single dose of measles-mumps-rubella (MMR) vaccine at one year of age.
DESIGN:
Cross-sectional study with a two stage cluster sampling of randomly picked schools across the province of Newfoundland.
STUDY POPULATION AND METHODS:
A total of 1053, five to 17-year-old children were enrolled; vaccination history was verified through official records; and a sample of blood was taken. Rubella immunity was determined by enzyme immunoassay based on a serum antibody protective cut-off titre of more than 10 IU.
RESULTS:
A total of 145 (13.8%) were found to be nonimmune. The rate of susceptibility ranged from 3.2% to 25.9% for different age groups. The proportion susceptible was significantly higher at 16.5% in the age group eight to 17 years old versus 3.9% for the age group five to eight years old (χ2=24.08; df=1, P<0.001). There was a significant regression of logarithm titre values on the age of children with an average decline in titre values of 8.1% per annum.
CONCLUSIONS:
A substantial number of those who were given a single dose of MMR II vaccine may not have protective immunity against rubella as they reach prime reproductive age. There is a definite need to consider a two-dose rubella vaccination strategy in Canada, and these data suggest the second dose given after eight years of age will be most beneficial. In the move towards a routine two-dose measles vaccination strategy in Canada, the MMR II vaccine is being used for the second dose and given either at 18 months of age or at school entry. While this approach will have an overall beneficial effect, the impact of the above timing of the second dose on long term rubella immunity cannot be predicted at this time. These data also underscore the continuing need for prenatal rubella screening program.
PMCID: PMC3327347  PMID: 22514481
Rubella immunity; Rubella seroscreening; Rubella vaccination
10.  Characterization of Regional Influenza Seasonality Patterns in China and Implications for Vaccination Strategies: Spatio-Temporal Modeling of Surveillance Data 
PLoS Medicine  2013;10(11):e1001552.
Cécile Viboud and colleagues describe epidemiological patterns of influenza incidence across China to support the design of a national vaccination program.
Please see later in the article for the Editors' Summary
Background
The complexity of influenza seasonal patterns in the inter-tropical zone impedes the establishment of effective routine immunization programs. China is a climatologically and economically diverse country, which has yet to establish a national influenza vaccination program. Here we characterize the diversity of influenza seasonality in China and make recommendations to guide future vaccination programs.
Methods and Findings
We compiled weekly reports of laboratory-confirmed influenza A and B infections from sentinel hospitals in cities representing 30 Chinese provinces, 2005–2011, and data on population demographics, mobility patterns, socio-economic, and climate factors. We applied linear regression models with harmonic terms to estimate influenza seasonal characteristics, including the amplitude of annual and semi-annual periodicities, their ratio, and peak timing. Hierarchical Bayesian modeling and hierarchical clustering were used to identify predictors of influenza seasonal characteristics and define epidemiologically-relevant regions. The annual periodicity of influenza A epidemics increased with latitude (mean amplitude of annual cycle standardized by mean incidence, 140% [95% CI 128%–151%] in the north versus 37% [95% CI 27%–47%] in the south, p<0.0001). Epidemics peaked in January–February in Northern China (latitude ≥33°N) and April–June in southernmost regions (latitude <27°N). Provinces at intermediate latitudes experienced dominant semi-annual influenza A periodicity with peaks in January–February and June–August (periodicity ratio >0.6 in provinces located within 27.4°N–31.3°N, slope of latitudinal gradient with latitude −0.016 [95% CI −0.025 to −0.008], p<0.001). In contrast, influenza B activity predominated in colder months throughout most of China. Climate factors were the strongest predictors of influenza seasonality, including minimum temperature, hours of sunshine, and maximum rainfall. Our main study limitations include a short surveillance period and sparse influenza sampling in some of the southern provinces.
Conclusions
Regional-specific influenza vaccination strategies would be optimal in China; in particular, annual campaigns should be initiated 4–6 months apart in Northern and Southern China. Influenza surveillance should be strengthened in mid-latitude provinces, given the complexity of seasonal patterns in this region. More broadly, our findings are consistent with the role of climatic factors on influenza transmission dynamics.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Every year, millions of people worldwide catch influenza, a viral disease of the airways. Most infected individuals recover quickly but seasonal influenza outbreaks (epidemics) kill about half a million people annually. These epidemics occur because antigenic drift—frequent small changes in the viral proteins to which the immune system responds—means that an immune response produced one year provides only partial protection against influenza the next year. Annual vaccination with a mixture of killed influenza viruses of the major circulating strains boosts this natural immunity and greatly reduces the risk of catching influenza. Consequently, many countries run seasonal influenza vaccination programs. Because the immune response induced by vaccination decays within 4–8 months of vaccination and because of antigenic drift, it is important that these programs are initiated only a few weeks before the onset of local influenza activity. Thus, vaccination starts in early autumn in temperate zones (regions of the world that have a mild climate, part way between a tropical and a polar climate), because seasonal influenza outbreaks occur in the winter months when low humidity and low temperatures favor the transmission of the influenza virus.
Why Was This Study Done?
Unlike temperate regions, seasonal influenza patterns are very diverse in tropical countries, which lie between latitudes 23.5°N and 23.5°S, and in the subtropical countries slightly north and south of these latitudes. In some of these countries, there is year-round influenza activity, in others influenza epidemics occur annually or semi-annually (twice yearly). This complexity, which is perhaps driven by rainfall fluctuations, complicates the establishment of effective routine immunization programs in tropical and subtropical countries. Take China as an example. Before a national influenza vaccination program can be established in this large, climatologically diverse country, public-health experts need a clear picture of influenza seasonality across the country. Here, the researchers use spatio-temporal modeling of influenza surveillance data to characterize the seasonality of influenza A and B (the two types of influenza that usually cause epidemics) in China, to assess the role of putative drivers of seasonality, and to identify broad epidemiological regions (areas with specific patterns of disease) that could be used as a basis to optimize the timing of future Chinese vaccination programs.
What Did the Researchers Do and Find?
The researchers collected together the weekly reports of laboratory-confirmed influenza prepared by the Chinese national sentinel hospital-based surveillance network between 2005 and 2011, data on population size and density, mobility patterns, and socio-economic factors, and daily meteorological data for the cities participating in the surveillance network. They then used various statistical modeling approaches to estimate influenza seasonal characteristics, to assess predictors of influenza seasonal characteristics, and to identify epidemiologically relevant regions. These analyses indicate that, over the study period, northern provinces (latitudes greater than 33°N) experienced winter epidemics of influenza A in January–February, southern provinces (latitudes less than 27°N) experienced peak viral activity in the spring (April–June), and provinces at intermediate latitudes experienced semi-annual epidemic cycles with infection peaks in January–February and June–August. By contrast, influenza B activity predominated in the colder months throughout China. The researchers also report that minimum temperatures, hours of sunshine, and maximum rainfall were the strongest predictors of influenza seasonality.
What Do These Findings Mean?
These findings show that influenza seasonality in China varies between regions and between influenza virus types and suggest that, as in other settings, some of these variations might be associated with specific climatic factors. The accuracy of these findings is limited by the short surveillance period, by sparse surveillance data from some southern and mid-latitude provinces, and by some aspects of the modeling approach used in the study. Further surveillance studies need to be undertaken to confirm influenza seasonality patterns in China. Overall, these findings suggest that, to optimize routine influenza vaccination in China, it will be necessary to stagger the timing of vaccination over three broad geographical regions. More generally, given that there is growing interest in rolling out national influenza immunization programs in low- and middle-income countries, these findings highlight the importance of ensuring that vaccination strategies are optimized by taking into account local disease patterns.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/ 10.1371/journal.pmed.1001552.
This study is further discussed in a PLOS Medicine Perspective by Steven Riley
The UK National Health Service Choices website provides information for patients about seasonal influenza and about influenza vaccination
The World Health Organization provides information on seasonal influenza (in several languages) and on influenza surveillance and monitoring
The US Centers for Disease Control and Prevention also provides information for patients and health professionals on all aspects of seasonal influenza, including information about vaccination; its website contains a short video about personal experiences of influenza.
Flu.gov, a US government website, provides access to information on seasonal influenza and vaccination
Information about the Chinese National Influenza Center, which is part of the Chinese Center for Disease Control and Prevention: and which runs influenza surveillance in China, is available (in English and Chinese)
MedlinePlus has links to further information about influenza and about vaccination (in English and Spanish)
A recent PLOS Pathogens Research Article by James D. Tamerius et al. investigates environmental predictors of seasonal influenza epidemics across temperate and tropical climates
A study published in PLOS ONE by Wyller Alencar de Mello et al. indicates that Brazil, like China, requires staggered timing of vaccination from Northern to Southern states to account for different timings of influenza activity.
doi:10.1371/journal.pmed.1001552
PMCID: PMC3864611  PMID: 24348203
11.  Evolutionary analysis of rubella viruses in mainland China during 2010–2012: endemic circulation of genotype 1E and introductions of genotype 2B 
Scientific Reports  2015;5:7999.
Rubella remains a significant burden in mainland China. In this report, 667 viruses collected in 24 of 31 provinces of mainland China during 2010–2012 were sequenced and analyzed, significantly extending previous reports on limited numbers of viruses collected before 2010. Only viruses of genotypes 1E and 2B were found. Genotype 1E viruses were found in all 24 provinces. Genotype 1E viruses were likely introduced into mainland China around 1997 and endemic transmission of primarily one lineage became established. Viruses reported here from 2010–2012 are largely in a single cluster within this lineage. Genotype 2B viruses were rarely detected in China prior to 2010. This report documents a previously undetected 2B lineage, which likely became endemic in eastern provinces of China between 2010 and 2012. Bayesian analyses were performed to estimate the evolutionary rates and dates of appearance of the genotype 1E and 2B viral linages in China. A skyline plot of viral population diversity did not provide evidence of reduction of diversity as a result of vaccination, but should be useful as a baseline for such reductions as vaccination programs for rubella become widespread in mainland China.
doi:10.1038/srep07999
PMCID: PMC4303870  PMID: 25613734
12.  Analysis of whole genome sequences of 16 strains of rubella virus from the United States, 1961–2009 
Virology Journal  2013;10:32.
Rubella virus is the causative agent of rubella, a mild rash illness, and a potent teratogenic agent when contracted by a pregnant woman. Global rubella control programs target the reduction and elimination of congenital rubella syndrome. Phylogenetic analysis of partial sequences of rubella viruses has contributed to virus surveillance efforts and played an important role in demonstrating that indigenous rubella viruses have been eliminated in the United States. Sixteen wild-type rubella viruses were chosen for whole genome sequencing. All 16 viruses were collected in the United States from 1961 to 2009 and are from 8 of the 13 known rubella genotypes. Phylogenetic analysis of 30 whole genome sequences produced a maximum likelihood tree giving high bootstrap values for all genotypes except provisional genotype 1a. Comparison of the 16 new complete sequences and 14 previously sequenced wild-type viruses found regions with clusters of variable amino acids. The 5′ 250 nucleotides of the genome are more conserved than any other part of the genome. Genotype specific deletions in the untranslated region between the non-structural and structural open reading frames were observed for genotypes 2B and genotype 1G. No evidence was seen for recombination events among the 30 viruses. The analysis presented here is consistent with previous reports on the genetic characterization of rubella virus genomes. Conserved and variable regions were identified and additional evidence for genotype specific nucleotide deletions in the intergenic region was found. Phylogenetic analysis confirmed genotype groupings originally based on structural protein coding region sequences, which provides support for the WHO nomenclature for genetic characterization of wild-type rubella viruses.
doi:10.1186/1743-422X-10-32
PMCID: PMC3574052  PMID: 23351667
Rubella virus; Whole genome
13.  Rubella Immunity in Women of Childbearing Age, Eight Years After the Immunization Program in Iran 
Background:
Rubella is a viral disease with a worldwide distribution. Mass vaccination campaigns have increased the vaccine coverage in the world with substantial impact on reduction of rubella infections. In Iran, the national measles-rubella campaign, targeting individuals 5-25 years old, was initiated in 2003 and mass childhood vaccination against measles, rubella and mumps has continued ever since.
Objectives:
The aim of this study was to evaluate the efficacy of routine vaccination on rubella immunity among women of childbearing age in Babol, north of Iran.
Patients and Methods:
This cross-sectional study was conducted on 812 women of childbearing age living in Babol, north of Iran, in 2011. Twelve samples were excluded from the study because of inadequate sera amounts. Serum samples were examined for presence of rubella-specific IgG antibodies by means of quantitative ELISA.
Results:
From a total of 800 samples in this study, rubella IgG seropositivity was seen in 786 (98.3% [95% CI = %97.5-%99.1]) cases. The maximum IgG seropositivity (99.2%) was seen in the age group of 21-25 years old and the lowest immunity (87.7%) was in the group of above 30 years old.
Conclusions:
Our data indicated that the rate of seropositivity to rubella virus in our population was high, suggesting that vaccination has been successful in Babol, reducing the likelihood of congenital rubella infection.
doi:10.5812/ircmj.10431
PMCID: PMC4166081  PMID: 25237562
Rubella; Congenital Rubella Syndrome; Immunity; Vaccination
14.  The ocular manifestations of congenital infection: a study of the early effect and long-term outcome of maternally transmitted rubella and toxoplasmosis. 
PURPOSE: To study the spectrum of adverse ocular effects which result from maternally transmitted rubella and toxoplasma infection; further, to record the long-term visual and neurodevelopmental outcomes of these 2 major causes of fetal infection. STUDY DESIGN AND PATIENTS: A series of 55 patients with congenital infection have been studied prospectively on a long-term basis. The study group included a cohort of 34 cases with congenital rubella syndrome demonstrated by virus isolation, and 21 cases with a clinical diagnosis of congenital toxoplasmosis and serologic confirmation. All patients had specific disease-related ocular defects. Rubella patients were first identified during or following the last major rubella epidemic in 1963-1964, and some have been followed serially since that time. A separate study group of representative toxoplasmosis patients presented for examination and diagnosis at varying time periods between 1967 and 1991. OBSERVATIONS AND RESULTS: This study confirms that a broad spectrum of fetal injury may result from intrauterine infection and that both persistent and delayed-onset effects may continue or occur as late as 30 years after original infection. Many factors contribute to the varied outcome of prenatal infection, the 2 most important being the presence of maternal immunity during early gestation and the stage of gestation during which fetal exposure occurs in a nonimmune mother. RUBELLA: As a criteria of inclusion, all 34 rubella patients in this study exhibited one or more ocular defects at the time of birth or in the immediate neonatal period. Cataracts were present in 29 (85%) of the 34, of which 21 (63%) were bilateral. Microphthalmia, the next most frequent defect, was present in 28 (82%) of the 34 infants and was bilateral in 22 (65%). Glaucoma was recorded in 11 cases (29%) and presented either as a transient occurrence with early cloudy cornea in microphthalmic eyes (4 patients), as the infantile type with progressive buphthalmos (1 patient), or as a later-onset, aphakic glaucoma many months or years following cataract aspiration in 11 eyes of 6 patients. Rubella retinopathy was present in the majority of patients, although an accurate estimate of its incidence or laterality was not possible because of the frequency of cataracts and nystagmus and the difficulty in obtaining adequate fundus examination. TOXOPLASMOSIS: Twenty-one patients with congenital toxoplasmosis have been examined and followed for varying time periods, 7 for 20 years or more. The major reason for initial examination was parental awareness of an ocular deviation. Twelve children (57%) presented between the ages of 3 months and 4 years with an initial diagnosis of strabismus, 9 of whom had minor complaints or were diagnosed as part of routine examinations. All cases in this study have had evidence of retinochoroiditis, the primary ocular pathology of congenital toxoplasmosis. Two patients had chronic and recurrent inflammation with progressive vitreal traction bands, retinal detachments, and bilateral blindness. Macular lesions were always associated with central vision loss; however, over a period of years visual acuity gradually improved in several patients. Individuals with more severe ocular involvement were also afflicted with the most extensive central nervous system deficits, which occurred following exposure during the earliest weeks of gestation. CONCLUSIONS: Although congenital infection due to rubella virus has been almost completely eradicated in the United States, the long-term survivors from the prevaccination period continue to experience major complications from their early ocular and cerebral defects. They may be afflicted by the persistence of virus in their affected organs and the development of late manifestations of their congenital infection. Congenital toxoplasmosis continues to be the source of major defects for 3,000 to 4,100 infants in the United States each year; the spectrum of defects is wide and may vary from blindness and severe mental retardation to minor retinochoroidal lesions of little consequence. Effective solutions for either the prevention or treatment of congenital toxoplasmosis have not been developed in this country but are under intensive and continuing investigation.
Images
PMCID: PMC1298415  PMID: 10360309
15.  Surveillance and vaccination coverage of measles and rubella in Northern Italy 
Measles and rubella are infectious diseases and humans are the only reservoir of these infections. Effective vaccines are available with the potential for measles (MV) and rubella (RuV) virus eradication. According to the World Health Organisation guidelines, a national plan was approved in Italy in 2013 to achieve the MV/RuV elimination by 2015, and active MV/RuV integrated surveillance initiated. Towards this purpose, a regional laboratory centre was set up on 1 September 2013 in Lombardy, Northern Italy. This paper aimed at: (1) evaluating measles-mumps-rubella (MMR) vaccine coverage and MV/RuV notified cases retrospectively; and (2) presenting the results of MV/RuV integrated surveillance (laboratory confirmed and viral genetic profiles).
The 95% target for MMR vaccine coverage was achieved in 2001, and coverage increased until 2007 (96.6%), but then a decreasing trend was observed. Since 2000 to 2014, 3026 rubella cases were notified, with nearly 58% of them in the 2002 epidemic. From 2009, less than 45 RuV cases per year were reported. From 2000 to 2014, 5024 measles cases were notified. Since 2008, three large outbreaks (in 2008, 2011, and 2013) were observed. From data obtained during our surveillance activity, there were no rubella cases, and 57.5% (46/80) collected samples were MV-positive by real-time RT-PCR. A fragment of the MV N gene was sequenced from 37 MV-positive samples; D8, D9, and B3 genotypes were detected.
Data obtained retrospectively and from active surveillance underline the necessity to achieve and maintain high vaccination coverage and to improve surveillance and the effectiveness of healthcare actions.
doi:10.4161/hv.35865
PMCID: PMC4514426  PMID: 25483537
Measles; rubella; measles and rubella integrated surveillance; MMR vaccine; vaccine coverage; epidemiology; phylogeny
16.  Congenital rubella syndrome in Iran 
Background
Congenital rubella syndrome (CRS) can be prevented with appropriate vaccination programs. The prevalence rates of rubella and CRS in Iran are unknown; therefore, the risk of exposure in pregnant women is not clear. The prevalence of CRS in the pre-vaccine period can be estimated by evaluating the proportion of children in the population with sensorineural hearing loss attributable to rubella.
Methods
This was a case-control study to estimate prevalence of CRS in Tehran (Iran) by evaluating the proportion of children with sensorineural hearing loss attributable to rubella. The study used rubella antibody titer as an indicator, and compared the prevalence of rubella antibody between children with and without sensorineural hearing loss. Using these findings, the proportion of cases of sensorineural hearing loss attributable to rubella was estimated.
Results
A total of 225 children aged 1 to 4 years were entered into the study (113 cases and 112 controls). There was a significant difference between cases and controls with regard to rubella antibody seropositivity (19.5% vs. 8.9%, respectively, odds ratio = 2.47, 95% CI = 1.04–5.97). The proportion of sensorineural hearing loss cases attributable to rubella was found to be 12%, corresponding to a CRS prevalence of 0.2/1000.
Conclusion
The prevalence of CRS was approximately 0.2/1000 before rubella vaccination in Iran, Moreover; the results suggest that implementation of appropriate rubella vaccination programs could potentially prevent about 12% of cases of sensorineural hearing loss in Iranian children. This data could potentially be used as baseline data, which in conjunction with an appropriate method, to establish a surveillance system for rubella vaccination in Iran. An appropriate surveillance system is needed, because the introduction of a rubella vaccine without epidemiological data and an adequate monitoring program could result in the shifting of rubella cases to higher ages, and increasing the incidence of CRS.
doi:10.1186/1471-2334-5-44
PMCID: PMC1175087  PMID: 15938744
17.  Rubella seroprevalence among primary and pre- primary school pupils at Moi's Bridge location, Uasin Gishu District, Kenya 
BMC Public Health  2009;9:269.
Background
Rubella is an infectious and generally mild childhood viral disease. The disease is of public health importance because infection acquired during early pregnancy often results in foetal abnormalities that are classified as congenital rubella syndrome (CRS). The burden of rubella infection in most developing countries in not well documented because of limited epidemiological data. However, availability of an effective vaccine has made it necessary to have all the countries with no routine vaccination schedule to evaluate the burden of disease in order to make informed decisions on rubella vaccination and strategy. To address this gap we conducted a study to determine age-specific rubella seroprevalence rates and related risk factors among primary and pre-primary school children in Uasin Gishu district, Moi's Bridge location of Kenya.
Methods
Subjects of the study were 498 pupils from seven primary schools aged 4–20 years. Questionnaire surveys with blood sampling were conducted between January to July 2005. Samples were tested for rubella specific IgG antibody using ELISA test kit (Enzygnost® Behring, Germany).
Results
Overall, rubella seropositivity rate was 80% and it increased with age from 59% (among ages 4–6 years) to 94% (ages 14–20 years). Multivariate logistic regression analysis model, showed that age of child and ownership of a television set which is a proxy measure of socio-economic status of family were significantly associated with rubella seropositivity. The odds of rubella seropositivity in a child older than 13 years was more than that in children younger than 7 years (OR = 3.8 95% CI 2.56–5.78). The odds of rubella seropositivity in a child whose family did not own a television set was 3 times higher than that of child whose family owned a set (OR 3.06, 95% CI 1.17–7.97).
Conclusion
The study provides important and highly useful information on rubella age specific seroprevalence rates in Kenya. Advancing age was found to be associated with increased risk of rubella. Low socio-economic factors suggest an increased risk of infection in certain categories of society, and control measures need to target this. Overall, the findings can also be used by policy makers to model introduction of routine rubella vaccination in the country and also other developing countries facing similar challenges. More than half of the children got infected in pre-primary and efforts to control rubella should target pre-school children. These data provides pre-vaccination information that can be used to guide immunization strategy as well as to determine success of an immunization programme.
doi:10.1186/1471-2458-9-269
PMCID: PMC2731100  PMID: 19640288
18.  Evaluation of Rubella Immunity in a Community Prenatal Clinic 
ISRN Family Medicine  2013;2013:602130.
Since the introduction of the Rubella vaccine in 1969, prevalence of congenital Rubella syndrome (CRS) has greatly declined in the United States. However, reports of sporadic adult cases of the disease and frequent identification of non-Rubella immune (NRI) women in prenatal units may result in outbreak of CRS in susceptible communities. Identifying populations with high rates of NRI will assist in evidence-based public health intervention that may prevent epidemic of CRS in the United States. Method. This is a retrospective, cross-sectional study involving chart audit of Rubella screening results of 642 women who attended a high-risk prenatal care at a northwestern Iowa clinic between January 1 and December 31, 2007. Results. NRI was found in 6.9% of the study population. The highest prevalence rate of 10.2% was found among adolescents. NRI was highest among Native American women at 17.3%, compared to Whites 7.3%, African Americans 5.9%, and Hispanics 4.6%. Multivariate analysis demonstrated that Native Americans were 2.5 times more likely to be NRI compared to Whites (OR 2.7; 95% CI: 1.1, 6.6). Conclusion. This study demonstrated higher rate of non-Rubella immunity among adolescent pregnant women and supports Rubella booster immunization for all non-pregnant teenage women. The observed high rate of NRI among Native Americans may require further studies and evaluation of Rubella vaccination programs in tribal communities.
doi:10.5402/2013/602130
PMCID: PMC4041247  PMID: 24967326
19.  Persistence and Titer Changes of Rubella Virus Antibodies in Primiparous Women Who Had Been Vaccinated with Strain RA 27/3 in Junior High School 
Taiwan's rubella vaccination program was launched in 1986; each schoolgirl in the third grade of junior high school received one dose of rubella (RA 27/3) vaccine. We reviewed the results of 14,090 prenatal rubella tests for primiparas from three areas of Taiwan during 2002 to 2008 to investigate seronegativity rates and titer changes. In all primiparous women, the average rubella virus seronegativity rate was 6.5% (95% confidence interval [95% CI], 6.1 to 6.9%), and the average rubella virus antibody titer was 65.9 IU/ml (95% CI, 64.7 to 67.1 IU/ml). There were 1,220 women (8.7%) with weakly positive antibody titers (10 to 20 IU/ml). The rubella virus seronegativity rates, which ranged from 5.4 to 9.7%, did not exhibit a linear trend from 9 to 22 years after vaccination (P = 0.201); in contrast, a significant trend appeared in the average rubella virus IgG titer (P = 0.003), dropping from 69.9 IU/ml in the 9th year after vaccination to 54.8 IU/ml in the 22nd year. The mean annual antibody decay rate was −0.77 IU/ml. This study reveals that the level of rubella virus antibodies declined slowly in women of childbearing age who were vaccinated with RA 27/3 at junior high school age. The number of women who were seronegative or had weakly positive antibody titers was still high (15.2%). Therefore, in countries that implement a single-dose regimen in children or teenagers, it should remain an important policy to encourage voluntary immunization in seronegative women and to immunize all postpartum women who are susceptible to rubella virus infection before they leave the hospital.
doi:10.1128/CVI.05334-11
PMCID: PMC3255950  PMID: 22072722
20.  Mass Measles Rubella Immunization Campaign: Bhutan Experience 
Background:
Bhutan has attained universal child immunization since 1991. Since then, immunization coverage is maintained at high level through routine immunization, periodic National Immunization Days, and mop up campaigns. Despite high immunization coverage, every year, significant numbers of clinically suspected measles cases were reported.
Objective:
To assess the cause of continuing high “suspected measles cases” and take appropriate public health measures.
Materials and Methods:
Febrile rash outbreaks occurred in several districts in 2003. These episodes were investigated. Simultaneously, a retrospective data search revealed evidence of congenital rubella syndrome (CRS) in the country.
Results:
Thirty five percent of the tested samples were positive for rubella but none for measles. There were evidences of the presence of CRS. This was discussed in the annual health conference 2004, amongst health policy makers and district heads who recommended that a possibility of inclusion of rubella as an antigen be looked into. A nationwide measles and rubella immunization campaign was conducted in 2006 followed by introduction of rubella vaccine in the immunization schedule.
Conclusion:
Febrile rash can be caused by a host of viral infections. Following universal measles immunization, it is pertinent that febrile rash be looked in the light of rubella infections. Following the introduction of rubella vaccination in the national immunization schedule, there has been significant reduction of febrile rash episodes, cases of rubella, and congenital rubella syndrome.
doi:10.4103/0970-0218.84128
PMCID: PMC3180934  PMID: 21976794
Campaign; congenital rubella syndrome; immunization; measles; rubella
21.  Simultaneous Detection of Measles Virus, Rubella Virus, and Parvovirus B19 by Using Multiplex PCR 
Journal of Clinical Microbiology  2002;40(1):111-116.
We describe here a multiplex reverse transcription-PCR (RTMNPCR) assay designed to detect and differentiate measles virus, rubella virus, and parvovirus B19. Serial dilution experiments with vaccine strains that compared cell culture isolation of measles in B95 cells and rubella in RK13 cells showed sensitivity rates of 0.004 50% tissue culture infective dose (TCID50) for measles virus and 0.04 TCID50 for rubella virus. This RTMNPCR can detect as few as 10 molecules for measles virus and rubella virus and one molecule for parvovirus B19 in dilution experiments with plasmids containing inserts of the primary reaction amplification products. Five pharyngeal exudates from measles patients and 2 of 15 cerebrospinal fluid samples from measles-related encephalitis were found to be positive for measles virus by this RTMNPCR. A total of 3 of 27 pharyngeal exudates from vaccinated children and 2 pharyngeal exudates, plus one urine sample from a case of congenital rubella syndrome, were found to be positive for rubella virus by RTMNPCR, whereas 16 of 19 sera from patients with erythema infectiosum were determined to be positive for parvovirus B19 by RTMNPCR. In view of these results, we can assess that this method is a useful tool in the diagnosis of these three viruses and could be used as an effective surveillance tool in measles eradication programs.
doi:10.1128/JCM.40.1.111-116.2002
PMCID: PMC120129  PMID: 11773102
22.  Rubella vaccine-induced cellular immunity: evidence of associations with polymorphisms in the Toll-like, vitamin A and D receptors, and innate immune response genes 
Human genetics  2009;127(2):207-221.
Toll-like, vitamin A and D receptors and other innate proteins participate in various immune functions. We determined whether innate gene-sequence variations are associated with rubella vaccine-induced cytokine immune responses. We genotyped 714 healthy children (11–19 years of age) after two doses of rubella-containing vaccine for 148 candidate SNP markers. Rubella virus-induced cytokines were measured by ELISA. Twenty-two significant associations (range of P values 0.002–0.048) were found between SNPs in the vitamin A receptor family (RARA, RARB, TOP2B and RARG), vitamin D receptor and downstream mediator of vitamin D signaling (RXRA) genes and rubella virus-specific (IFN-γ, IL-2, IL-10, TNF-α, and GM-CSF) cytokine immune responses. A TLR3 gene promoter region SNP (rs5743305, −8441A > T) was associated with rubella-specific GM-CSF secretion. Importantly, SNPs in the TRIM5 gene coding regions, rs3740996 (His43Tyr) and rs10838525 (Gln136Arg), were associated with an allele dose-related secretion of rubella virus-specific TNF-α and IL-2/GM-CSF, respectively, and have been previously shown to have functional consequences regarding the antiviral activity and susceptibility to HIV-1 infection. We identified associations between individual SNPs and haplotypes in, or involving, the RIG-I (DDX58) gene and rubella-specific TNF-α secretion. This is the first paper to present evidence that polymorphisms in the TLR, vitamin A, vitamin D receptor, and innate immunity genes can influence adaptive cytokine responses to rubella vaccination.
doi:10.1007/s00439-009-0763-1
PMCID: PMC2809817  PMID: 19902255
23.  Epidemiological Studies on Rubella 
Serological surveys of rubella antibody were carried out using the hemagglutination-inhibition test, with a view to studying the distribution of seroimmune individuals according to age and intermingling with other populations. Specimens were collected from different age groups including infants, children and adults, among the inhabitants of Montreal from 1963 to 1968. From the results obtained it was possible to establish the pattern of rubella antibody development in this urban community. Surveys were also conducted among the inhabitants of Les Iles de la Madeleine, a Canadian island in the Gulf of St. Lawrence, and among the population of Easter Island, an isolated island in the South Pacific remote from any large land mass.
It was seen that, among the inhabitants of Montreal, presumably maternally acquired rubella antibody was present in 95% or more of the infants, the same percentage of seroimmune individuals as was found among the adult women 25 to 30 years of age. Passively acquired rubella antibodies decreased rapidly, attaining their lowest levels among children 1 to 2 years old. Rubella infection occurred in young children and its incidence rose steeply from school age to adolescence, leaving 7 to 9% of the adults without antibody. The highest geometric mean antibody titres were found among children 4 to 10 years of age.
The same pattern of rubella antibody development was found among the population of Les Iles de la Madeleine, except that in adults the percentages of seropositives reached practically 100%. Antibody titres decreased with advancing age and became lower than those found among children.
Detection of rubella antibody in serum samples derived from the inhabitants of Easter Island indicated that this population had experienced rubella infection not long before the Canadian Medical Expedition of 1964-1965. This status is determined from the high proportion of seroimmune individuals in each age group and the uniformly high antibody titre.
Island populations appear to represent the ideal subjects for estimating the duration of the immunity conferred by any attenuated rubella vaccine that will eventually be licensed.
PMCID: PMC1946718  PMID: 5538492
24.  Single Endemic Genotype of Measles Virus Continuously Circulating in China for at Least 16 Years 
PLoS ONE  2012;7(4):e34401.
The incidence of measles in China from 1991 to 2008 was reviewed, and the nucleotide sequences from 1507 measles viruses (MeV) isolated during 1993 to 2008 were phylogenetically analyzed. The results showed that measles epidemics peaked approximately every 3 to 5 years with the range of measles cases detected between 56,850 and 140,048 per year. The Chinese MeV strains represented three genotypes; 1501 H1, 1 H2 and 5 A. Genotype H1 was the predominant genotype throughout China continuously circulating for at least 16 years. Genotype H1 sequences could be divided into two distinct clusters, H1a and H1b. A 4.2% average nucleotide divergence was found between the H1a and H1b clusters, and the nucleotide sequence and predicted amino acid homologies of H1a viruses were 92.3%–100% and 84.7%–100%, H1b were 97.1%–100% and 95.3%–100%, respectively. Viruses from both clusters were distributed throughout China with no apparent geographic restriction and multiple co-circulating lineages were present in many provinces. Cluster H1a and H1b viruses were co-circulating during 1993 to 2005, while no H1b viruses were detected after 2005 and the transmission of that cluster has presumably been interrupted. Analysis of the nucleotide and predicted amino acid changes in the N proteins of H1a and H1b viruses showed no evidence of selective pressure. This study investigated the genotype and cluster distribution of MeV in China over a 16-year period to establish a genetic baseline before MeV elimination in Western Pacific Region (WPR). Continuous and extensive MeV surveillance and the ability to quickly identify imported cases of measles will become more critical as measles elimination goals are achieved in China in the near future. This is the first report that a single endemic genotype of measles virus has been found to be continuously circulating in one country for at least 16 years.
doi:10.1371/journal.pone.0034401
PMCID: PMC3332093  PMID: 22532829
25.  A rubella vaccination program for women entering the U.S. Army. 
Public Health Reports  1979;94(6):564-567.
A voluntary rubella vaccination program for female basic trainees was initiated on April 21, 1975, at Fort Jackson, S.C. A total of 29,852 women were tested for rubella titers between April 21, 1975, and December 31, 1977, and 6,167 were found to be nonimmune. An average of 53 percent of the susceptible women were vaccinated. The best results were obtained from August 1 to December 31, 1977, when 67 percent of the susceptible women were vaccinated. During this period, blood specimens for rubella titer and for pregnancy testing were obtained simultaneously. This procedure reduced the number of referrals to the Obstetrics-Gynecology Clinic, as well as the amount of training time lost when pregnancy testing and rubella titer testing were done on separate days. Despite the vaccination program, however, rubella epidemics occurred among female trainees at Fort Jackson in 1975, 1976, and 1977. A significant number of women are still susceptible to rubella. To reduce morbidity and the risk of congenital rubella syndrome, rubella titer testing and immunization of susceptibles should be considered for women-especially where they can be screened, counseled, and vaccinated en masse.
PMCID: PMC1431739  PMID: 515343

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