In order to control and eliminate the vaccine preventable diseases it is important to know the vaccination coverage and reasons for non-vaccination. The primary objective of this study was to determine the complete vaccination rate; the reasons for non-vaccination and the predictors that influence vaccination of children. The other objective was to determine coverage of measles vaccination of the Measles Immunization Days (MID) 2005 for children aged 9 month to 6 years in a region of Umraniye, Istanbul, Turkey.
A '30 × 7' cluster sampling design was used as the sampling method. Thirty streets were selected at random from study area. Survey data were collected by a questionnaire which was applied face to face to parents of 221 children. A Chi-square test and logistic regression was used for the statistical analyses. Content analysis method was used to evaluate the open-ended questions.
The complete vaccination rate for study population was 84.5% and 3.2% of all children were totally non-vaccinated. The siblings of non-vaccinated children were also non-vaccinated. Reasons for non-vaccination were as follows: being in the village and couldn't reach to health care services; having no knowledge about vaccination; the father of child didn't allow vaccination; intercurrent illness of child during vaccination time; missed opportunities like not to shave off a vial for only one child. In logistic regression analysis, paternal and maternal levels of education and immigration time of both parents to Istanbul were found to influence whether children were completely vaccinated or non-vaccinated. Measles vaccination coverage during MID was 79.3%.
Efforts to increase vaccination coverage should take reasons for non-vaccination into account.
The main challenge of vaccine control of poliomyelitis in the 1980s is in the subtropical and tropical regions of the world where "lameness" surveys in recent years have shown how very high the average annual incidence of paralytic poliomyelitis can be in both rural and urban areas in the absence of epidemics. The procedures by which oral polio vaccine (OPV) rapidly eliminated all or almost all paralytic disease caused by polioviruses from the economically developed temperate climate countries have been inadequate in tropical and subtropical countries, except in some small countries with good health services, largely because there is much more year-round circulation of "wild" polioviruses which continue to produce the disease in the unvaccinated and incompletely vaccinated children. Not even a cheap, hypothetically 100 percent effective, one-dose vaccine could eliminate poliomyelitis in the tropics if, for a variety of reasons, it would reach only a portion of the infant population. Paralytic disease caused by polioviruses has been quickly eliminated from both small and large tropical countries by OPV in well-organized programs of annual mass vaccinations of almost all children under a certain age.
A chickenpox vaccine was recently licensed in Canada. Because this vaccine has caused some controversy within the health care profession, studies among Quebec parents and vaccine providers were carried out, surveying their opinions concerning chickenpox vaccination.
Three studies among parents of preadolescents, parents of two-year-old children completely or incompletely vaccinated and vaccinators were completed. The studies asked for opinions concerning the usefulness of vaccinating children against chickenpox.
The majority of parents of preadolescents (56%), and parents of two-year-old children completely (64%) and incompletely vaccinated (60%) favoured chickenpox vaccination. Among vaccinators, 53% of paediatricians, 37% of general practitioners and 33% of nurses considered universal vaccination of young children to be useful. A greater proportion of health care professionals were in favour of a policy of vaccinating groups at risk, such as susceptible adolescents (86%, 75% and 58%, respectively). There was a positive association between the perceived severity of chickenpox and the potential usefulness of the vaccine.
Quebec parents are more favourably disposed to chickenpox vaccine than vaccine providers. In contrast, strategies targeting susceptible groups would be generally well received by health care professionals. A considerable amount of work will be needed to convince vaccinators of the benefits of a universal childhood vaccination against chickenpox.
Chickenpox; Immunization programs; Parental opinions; Vaccinator opinions; Varicella vaccine
OBJECTIVE: The availability of a single vaccine active against hepatitis A and B may facilitate prevention of both infections, but complicates the question of whether to conduct pre-vaccination screening. The authors examined the cost-effectiveness of pre-vaccination screening for several populations: first-year college students, military recruits, travelers to hepatitis A-endemic areas, patients at sexually transmitted disease clinics, and prison inmates. METHODS: Three prevention protocols were examined: (1) screen and defer vaccination until serology results are known; (2) screen and begin vaccination immediately to avoid a missed vaccination opportunity; and (3) vaccinate without screening. Data describing pre-vaccination immunity, vaccine effectiveness, and prevention costs borne by the health system (i.e., serology, vaccine acquisition, and administration) were derived from published literature and U.S. government websites. Using spreadsheet models, the authors calculated the ratio of prevention costs to the number of vaccine protections conferred. RESULTS: The vaccinate without screening protocol was most cost-effective in nine of 10 analyses conducted under baseline assumptions, and in 69 of 80 sensitivity analyses. In each population considered, vaccinate without screening was less costly than and at least equally as effective as screen and begin vaccination. The screen and defer vaccination protocol would reduce costs in seven populations, but effectiveness would also be lower. CONCLUSIONS: Unless directed at vaccination candidates with the highest probability of immunity, pre-vaccination screening for hepatitis A and B immunity is not cost-effective. Balancing cost reduction with reduced effectiveness, screen and defer may be preferred for older travelers and prison inmates.
BACKGROUND: Immunization remains the primary strategy in both the control and prevention of common childhood diseases, particularly in the developing world. Immunization and preprimary health care services were commenced in a rural community in Nigeria in 1998, when vaccine coverage for all Expanded Program on Immunization (EPI) diseases (tuberculosis, polio, diphtheria, pertussis, tetanus, measles, and hepatitis B) was considerably low with only 43% of children fully immunized. METHODS: Children aged 0-2 years and living in a rural community were recruited into the study. Data on vaccination history was collected by both vaccination card and maternal history. Three hundred and twenty-seven children were recruited into the study. Study participants were vaccinated for EPI diseases. Hepatitis-B vaccine was administered at birth, and a combined diphtheria and tetanus toxoids, and pertussis whole cell vaccine (DTP) plus hepatitis-B vaccine was administered in a single injection after six weeks. RESULTS AND CONCLUSIONS: Two years after the program was started, immunization coverage rates were 94% for BCG, 88% for DTP (third dose), and 82% for measles. All antigens showed significant improvements from baseline values (p < 0.0001). Eighty four percent of children were fully immunized against all six diseases, compared with 43% at the commencement (p < 0.0001). Hepatitis-B coverage (three doses) was 58%. The vaccination program has significantly improved vaccination coverage and could be a model for under served, non-industrialized communities.
The optimum age for measles vaccination varies from country to country and thus a standardized vaccination schedule is controversial. While the increase in measles vaccination coverage has produced significant changes in the epidemiology of infection, vaccination schedules have not been adjusted. Instead, measures to cut wild-type virus transmission through mass vaccination campaigns have been instituted. This study estimates the presence of measles antibodies among six- and nine-month-old children and assesses the current vaccination seroconversion by using a non invasive method in Maputo City, Mozambique.
Six- and nine-month old children and their mothers were screened in a cross-sectional study for measles-specific antibodies in oral fluid. All vaccinated children were invited for a follow-up visit 15 days after immunization to assess seroconversion.
82.4% of the children lost maternal antibodies by six months. Most children were antibody-positive post-vaccination at nine months, although 30.5 % of nine month old children had antibodies in oral fluid before vaccination. We suggest that these pre-vaccination antibodies are due to contact with wild-type of measles virus. The observed seroconversion rate after vaccination was 84.2%.
These data indicate a need to re-evaluate the effectiveness of the measles immunization policy in the current epidemiological scenario.
We described the uptake and coverage rates of meningococcal conjugate vaccine (MCV4); tetanus-diphtheria-acellular pertussis vaccine (Tdap); and quadrivalent human papillomavirus vaccine (HPV4) in North Dakota using the North Dakota Immunization Information System (NDIIS).
We analyzed all available MCV4, Tdap, and HPV4 doses given after vaccine licensure and through December 31, 2009, obtained from the NDIIS to identify trends and patterns in vaccine administration. We analyzed all data by administration date, age group, and health-care provider type. We also calculated missed opportunities to complete all recommended vaccines among vaccinated adolescents.
For adolescents aged 13–17 years, 69.2% had ≥1 dose of Tdap and 62.8% had ≥1 dose of MCV4. Of females aged 13–17 years, 42.8% initiated the HPV4 vaccination series and 24.9% received ≥3 HPV4 doses. Only 48.7% of males aged 13–17 years received both Tdap and MCV4 at the same visit, and only 11.5% of females aged 13–17 years received Tdap, MCV4, and HPV4 doses at the first visit.
The NDIIS is useful in tracking adolescent vaccine uptake. The immunization rates for all three routinely recommended adolescent vaccines are rising in North Dakota, although at different paces. Providers should be educated about the importance of not missing opportunities to vaccinate, and school-based vaccination clinics should be used to reach adolescents who are less likely to have preventive care visits.
OBJECTIVE: To determine the vaccination rate among infants discharged from a neonatal intensive care unit (NICU) and factors affecting that rate. DESIGN: Cross-sectional survey conducted when the children were 12 to 18 months of age. SETTING: NICU at the Royal University Hospital, Saskatoon, Sask. PARTICIPANTS: All 395 infants discharged from the NICU between Jan. 1 and June 30, 1992. MAIN OUTCOME MEASURES: Vaccination rate, ethnic background (native or non-native), place of residence (urban or rural), health status (number of days spent in the NICU), reasons for delay in or incomplete vaccinations (those involving parents' responsibility, infant illness or contraindications). RESULTS: Of the 395 infants, 20 (5.0%) had died and incomplete information was available for 30 (7.6%). Complete data were available for 345 (87.3%). Of the infants for whom data were available, 8 (2.3%) had never been vaccinated and 142 (41.2%) had a delayed vaccination schedule or had not completed their scheduled vaccinations. Only 195 (56.6%) of the infants had received a full vaccination series. Non-native ethnic background was a predictor of completed vaccinations (odds ratio [OR] 5.40, 95% confidence interval [CI] 3.05 to 9.52). In a univariate model, urban area of residence was not a significant predictor of vaccination status, but when ethnic background was controlled for in a multivariate logistic regression analysis, urban area of residence was found to be inversely associated with completed vaccinations (OR 0.34, 95% CI 0.15 to 0.79). The number of days the child had spent in the NICU was not a significant predictor of vaccination status. CONCLUSION: The vaccination rate of infants discharged from the NICU is not optimal. Urban native children appears to be at risk of not being vaccinated. Non-native infants are five times more likely than native infants to have completed all of their scheduled vaccinations. Methods to improve the rate of completed vaccinations, especially for native children, must be sought and tested.
Vaccine-preventable diseases are responsible for severe rates of morbidity and mortality in Africa. Despite the availability of appropriate vaccines for routine use on infants, vaccine-preventable diseases are highly endemic throughout sub-Saharan Africa. Widespread disparities in the coverage of immunization programmes persist between and within rural and urban areas, regions and communities in Nigeria. This study assessed the individual- and community-level explanatory factors associated with child immunization differentials between migrant and non-migrant groups.
The proportion of children that received each of the eight vaccines in the routine immunization schedule in Nigeria was estimated. Multilevel multivariable regression analysis was performed using a nationally representative sample of 6029 children from 2735 mothers aged 15-49 years and nested within 365 communities. Odds ratios with 95% confidence intervals were used to express measures of association between the characteristics. Variance partition coefficients and Wald statistic i.e. the ratio of the estimate to its standard error were used to express measures of variation.
Individual- and community contexts are strongly associated with the likelihood of receiving full immunization among migrant groups. The likelihood of full immunization was higher for children of rural non-migrant mothers compared to children of rural-urban migrant mothers. Findings provide support for the traditional migration perspectives, and show that individual-level characteristics, such as, migrant disruption (migration itself), selectivity (demographic and socio-economic characteristics), and adaptation (health care utilization), as well as community-level characteristics (region of residence, and proportion of mothers who had hospital delivery) are important in explaining the differentials in full immunization among the children.
Migration is an important determinant of child immunization uptake. This study stresses the need for community-level efforts at increasing female education, measures aimed at alleviating poverty for residents in urban and remote rural areas, and improving the equitable distribution of maternal and child health services.
Vaccines are the most effective public health intervention. Expanded Program on Immunization (EPI) provides routine vaccination in developing countries. However, vaccines that cannot be given in EPI schedule such as typhoid fever vaccine need alternative venues. In areas where school enrolment is high, schools provide a cost effective opportunity for vaccination. Prior to start of a school-based typhoid vaccination program, interviews were conducted with staff of educational institutions in two townships of Karachi, Pakistan to collect baseline information about the school system and to plan a typhoid vaccination program. Data collection teams administered a structured questionnaire to all schools in the two townships. The administrative staff was requested information on school fee, class enrolment, past history of involvement and willingness of parents to participate in a vaccination campaign.
A total of 304,836 students were enrolled in 1,096 public, private, and religious schools (Madrasahs) of the two towns. Five percent of schools refused to participate in the school census. Twenty-five percent of schools had a total enrolment of less than 100 students whereas 3% had more than 1,000 students. Health education programs were available in less than 8% of public schools, 17% of private schools, and 14% of Madrasahs. One-quarter of public schools, 41% of private schools, and 43% of Madrasahs had previously participated in a school-based vaccination campaign. The most common vaccination campaign in which schools participated was Polio eradication program. Cost of the vaccine, side effects, and parents' lack of information were highlighted as important limiting factors by school administration for school-based immunization programs. Permission from parents, appropriateness of vaccine-related information, and involvement of teachers were considered as important factors to improve participation.
Health education programs are not part of the regular school curriculum in developing countries including Pakistan. Many schools in the targeted townships participated in immunization activities but they were not carried out regularly. In the wake of low immunization coverage in Pakistan, schools can be used as a potential venue not only for non-EPI vaccines, but for a catch up vaccination of routine vaccines.
Vaccine; typhoid fever; developing country; infectious disease; health education
OBJECTIVE: To provide, for family physicians without access to a travel clinic, evidence-based recommendations on vaccinating infants and children, adults, pregnant women, and immunocompromised patients traveling to non-Western countries. QUALITY OF EVIDENCE: Searches were undertaken of MEDLINE from 1990 to November 1998 (372 articles); the Cochrane Collaboration Library; publications of the National Action Committee on Immunization and the Committee to Advise on Tropical Medicine and Travel in Canada Communicable Disease Reports; the Canadian Immunization Guide; and Laboratory Centre for Disease Control, United States Centres for Disease Control, and World Health Organization websites. Evidence-based statements, randomized controlled trials, systematic reviews, and meta-analyses were selected. Vaccination recommendations are based on this evidence. MAIN MESSAGE: Physicians should complete vaccination schedules for children whose primary series is incomplete and vaccinate unvaccinated adults. Hepatitis A is widespread, and travelers to areas where it is endemic should be vaccinated. The elderly should be vaccinated against influenza and pneumococcal disease. Pregnant women should receive vaccines appropriate to their trimester. Immunocompromised patients should be vaccinated, but BCG and live vaccines are contraindicated. Travelers to areas where meningitis, typhoid, cholera, Japanese encephalitis, and rabies are endemic should be vaccinated if they are likely to be exposed. Those traveling to areas where tuberculosis is endemic should take precautions and should have skin tests before traveling and 2 to 4 months after return. CONCLUSIONS: Family physicians can administer all necessary vaccinations. They can advise pregnant women and immunocompromised people about the balance of risk of disease and benefits of vaccination.
Reasons for the low coverage of immunization vary from logistic ones to those dependent on human behaviour. The study was planned to find out: (a) the immunization status of children admitted to a paediatric ward of tertiary-care hospital in Delhi, India and (b) reasons for partial immunization and non-immunization. Parents of 325 consecutively-admitted children aged 12–60 months were interviewed using a semi-structured questionnaire. A child who had missed any of the vaccines given under the national immunization programme till one year of age was classified as partially-immunized while those who had not received any vaccine up to 12 months of age or received only pulse polio vaccine were classified as non-immunized. Reasons for partial/non-immunization were recorded using open-ended questions. Of the 325 children (148 males, 177 females), 58 (17.84%) were completely immunized, 156 (48%) were partially immunized, and 111 (34.15%) were non-immunized. Mothers were the primary respondents in 84% of the cases. The immunization card was available with 31.3% of the patients. All 214 partially- or completely-immunized children received BCG, 207 received OPV/DPT1, 182 received OPV/DPT2, 180 received OPV/DPT3, and 115 received measles vaccines. Most (96%) received pulse polio immunization, including 98 of the 111 non-immunized children. The immunization status varied significantly (p<0.05) with sex, education of parents, urban/rural background, route and place of delivery. On logistic regression, place of delivery [odds ratio (OR): 2.3, 95% confidence interval (CI) 1.3–4.1], maternal education (OR=6.94, 95% CI 3.1–15.1), and religion (OR=1.75, 95% CI 1.2–3.1) were significant (p<0.05). The most common reasons for partial or non-immunization were: inadequate knowledge about immunization or subsequent dose (n=140, 52.4%); belief that vaccine has side-effects (n=77, 28.8%); lack of faith in immunization (n=58, 21.7%); or oral polio vaccine is the only vaccine required (n=56, 20.9%. Most (82.5%) children admitted to a tertiary-care hospital were partially immunized or non-immunized. The immunization status needs to be improved by education, increasing awareness, and counselling of parents and caregivers regarding immunizations and associated misconceptions as observed in the study.
Child; Immunization; Vaccination; India
To estimate the impact of missed opportunities on influenza vaccination coverage among 6 through 23 month old children who sought medical care during the 2004–2005 influenza season.
Retrospective cohort study
Fifty two primary care practice sites located in Rochester New York, Nashville Tennessee and Cincinnati Ohio
Children 6 through 23 months of age
Charts were reviewed and data collected on influenza vaccinations, type of health care visit (well-child or other), and presence of illness symptoms. Missed opportunity was defined as a practice visit by an eligible child during influenza season, when vaccine was available, but during which the child did not receive an influenza vaccination. Vaccine was assumed to be available between the first and last dates influenza vaccination was recorded at that practice. Each child was classified as fully vaccinated, partially vaccinated or unvaccinated.
Data were analyzed for 1724 children 6 through 23 months. Most children (62.0%) had at least one missed opportunity during this period. Among children with any missed opportunities, 12.8% were fully and 29.8% were partially vaccinated. Overall, 33.6% of missed opportunities occurred during well child visits and 66.4% during other types of visits; 75% occurred when no other vaccines were given. Eliminating all missed opportunities would have increased full vaccination coverage from 30.3% to 49.9%.
Missed opportunities for influenza vaccination are frequent. Reducing missed opportunities could significantly increase influenza vaccination rates and should be a goal in each practice.
vaccination; child health services; influenza; human
The introduction of pneumococcal conjugate vaccine (PCV) to the U.S. recommended childhood immunization schedule in the year 2000 added three injections to the number of vaccinations a child is expected to receive during the first year of life. Surveys have suggested that the addition of PCV has led some immunization providers to move other routine childhood vaccinations to later ages, which could increase the possibility of missing these vaccines. The purpose of this study was to evaluate whether introduction of PCV affected immunization coverage for recommended childhood vaccinations among 13-month olds in four large provider groups.
In this retrospective cohort study, we analyzed computerized data on vaccinations for 33,319 children in four large provider groups before and after the introduction of PCV. The primary outcome was whether the child was up to date for all non-PCV recommended vaccinations at 13 months of age. Logistic regression was used to evaluate the association between PCV introduction and the primary outcome. The secondary outcome was the number of days spent underimmunized by 13 months. The association between PCV introduction and the secondary outcome was evaluated using a two-part modelling approach using logistic and negative binomial regression.
Overall, 93% of children were up-to-date at 13 months, and 70% received all non-PCV vaccinations without any delay. Among the entire study population, immunization coverage was maintained or slightly increased from the pre-PCV to post-PCV periods. After multivariate adjustment, children born after PCV entered routine use were less likely to be up-to-date at 13 months in one provider group (Group C: OR = 0.5; 95% CI: 0.3 – 0.8) and were less likely to have received all vaccine doses without any delay in two Groups (Group B: OR = 0.4, 95% CI: 0.3 – 0.6; Group C: OR = 0.5, 95% CI: 0.4 – 0.7). This represented 3% fewer children in Group C who were up-to-date and 14% (Group C) to 16% (Group B) fewer children who spent no time underimmunized at 13 months after PCV entered routine use compared to the pre-PCV baseline. Some disruptions in immunization delivery were also observed concurrent with temporary recommendations to suspend the birth dose of hepatitis B vaccine, preceding the introduction of PCV.
These findings suggest that the introduction of PCV did not harm overall immunization coverage rates in populations with good access to primary care. However, we did observe some disruptions in the timely delivery of other vaccines coincident with the introduction of PCV and the suspension of the birth dose of hepatitis B vaccine. This study highlights the need for continued vigilance in coming years as the U.S. introduces new childhood vaccines and policies that may change the timing of existing vaccines.
Malaria is a leading cause of mortality and morbidity in Mozambique, with nearly three-quarters of the country’s malaria-related deaths occurring in children younger than five years. A malaria vaccine is not yet available, but planning is underway for a possible introduction, as soon as one becomes available. In an effort to inform the planning process, this study explored sociocultural and health communications issues among individuals at the community level who are both responsible for decisions about vaccine use and who are likely to influence decisions about vaccine use.
Researchers conducted a qualitative study in two malaria-endemic districts in southern Mozambique. Using criterion-based sampling, they conducted 23 focus group discussions and 26 in-depth interviews. Implementation was guided by the engagement of community stakeholders.
Community members recognize that malaria contributes to high death rates and affects the workforce, school attendance, and the economy. Vaccines are seen as a means to reduce the threat of childhood illnesses and to keep children and the rest of the community healthy. Perceived constraints to accessing vaccine services include long queues, staff shortages, and a lack of resources at health care facilities. Local leaders play a significant role in motivating caregivers to have their children vaccinated. Participants generally felt that a vaccine could help to prevent malaria, although some voiced concern that the focus was only on young children and not on older children, pregnant women, and the elderly. Probed on their understanding of vaccine efficacy, participants voiced various views, including the perception that while some vaccines did not fully prevent disease they still had important benefits. Overall, it would be essential for local leaders to be involved in the design of specific messages for a future malaria vaccine communications strategy, and for those messages to be translated into local languages.
Acceptance of routine childhood vaccines bodes well for a future malaria vaccine. Vaccinating children is a well-established routine that is viewed favourably in Mozambique. A communications strategy would need to build on existing immunization efforts and use trusted sources—including current government dissemination arrangements—to deliver health information.
Formative studies; Vaccination; Malaria; Children; Communities; Health communications
AIM—To assess the
potential for administering catch up and scheduled immunisations during
status according to the child's principal carer was checked against
official records for 1000 consecutively admitted preschool age
children. Junior doctors were instructed to offer appropriate
vaccination before discharge, and consultants were asked to reinforce
this proactive policy on ward rounds.
those children who were not fully immunised against pertussis through
parental choice, 142 children (14.2%) had missed an age appropriate
immunisation and 41 were due a scheduled immunisation. None had a valid
contraindication. Only 43 children were offered vaccination on the ward
but uptake was 65% in this group.
to hospital provides opportunities for catch up and routine
immunisations and can contribute to the health care of an often
disadvantaged group of children. These opportunities are frequently
missed. Junior doctors must be encouraged to see opportunistic
immunisation as an important part of their routine work.
Bordetella pertussis is a gram-negative bacillus that causes the highly contagious disease known as pertussis or whooping cough. Antibody response in children may vary depending on the vaccination schedule and the product used. In this study, we have analyzed the antibody response of cellular pertussis vaccinated children against B. pertussis strains and their virulence factors, such as pertussis toxin, pertactin, and filamentous hemagglutinin. After the completion of the immunization process, according to the Brazilian vaccination program, children serum samples were collected at different periods of time, and tested for the presence of specific antibodies and antigenic cross-reactivity. Results obtained show that children immunized with three doses of the Brazilian whole-cell pertussis vaccine present high levels of serum antibodies capable of recognizing the majority of the components present in vaccinal and non-vaccinal B. pertussis strains and their virulence factors for at least 2 years after the completion of the immunization procedure.
Immunization is one of the most important public health interventions and a cost effective strategy to control the infectious diseases especially in children. Complete immunization coverage in India has increased from below 20% in the 1980s to nearly 61% at present, but still more than 1/3rd children remain un-immunized. Advent of combination vaccines has facilitated incorporation of additional vaccines into immunization schedule. Pentavalent vaccine, against five killer diseases–diphtheria, pertussis, tetanus, hepatitis B and Hemophilus influenza type B (Hib), has been introduced in almost all GAVI eligible countries by 2011. Government of India introduced the vaccine in two states in pilot phase and has given green signal to six more states. The use of pentavalent vaccine automatically raises the coverage level of hepatitis B and Hib vaccines. If the vaccines are provided individually, the coverage of hepatitis B and Hib vaccines usually lags behind DPT coverage. This gap can be filled by using pentavalent vaccine in routine immunization programmes.
Haemophilus influenza type b; DPT; cost-effectiveness; hepatitis B; immunization; immunogenicity; pentavalent vaccine
In many Tennessee counties, children under the care of health departments have low measles vaccination levels. An immunization survey and a health department record audit of 2-year-olds were undertaken in two counties to determine the reasons for this situation. The results indicated that faulty clinic procedures played a large part in the failure to vaccinate against measles. Nearly half of the unvaccinated 2-year-olds with health department records had been present in the health department clinic at the appropriate age for measles vaccination; the remainder had dropped out of the well-child program before their first birthday. Emphasis on tuberculin skin testing and delay in the administration of the basic series of DTP immunizations correlated with the failure to vaccinate against measles. For more than half of the children who attended the clinic after their first birthday, no reason was recorded for the failure to vaccinate them against measles. Improved clinic procedures could bring measles vaccination levels within the acceptable range. These procedures would include new methods for correcting immunization delinquency, simultaneous tuberculin skin testing and measles vaccination of children without a history of tuberculosis exposure, emphasis on vaccinating at-risk groups, and more convenient vaccination clinic hours.
Childhood immunization is a cost effective public health strategy. Expanded Programme on Immunisation (EPI) services have been provided in a rural Nigerian community (Sabongidda-Ora, Edo State) at no cost to the community since 1998 through a privately financed vaccination project (private public partnership). The objective of this survey was to assess vaccination coverage and its determinants in this rural community in Nigeria
A cross-sectional survey was conducted in September 2006, which included the use of interviewer-administered questionnaire to assess knowledge of mothers of children aged 12–23 months and vaccination coverage. Survey participants were selected following the World Health Organization's (WHO) immunization coverage cluster survey design. Vaccination coverage was assessed by vaccination card and maternal history. A child was said to be fully immunized if he or she had received all of the following vaccines: a dose of Bacille Calmette Guerin (BCG), three doses of oral polio (OPV), three doses of diphtheria, pertussis and tetanus (DPT), three doses of hepatitis B (HB) and one dose of measles by the time he or she was enrolled in the survey, i.e. between the ages of 12–23 months. Knowledge of the mothers was graded as satisfactory if mothers had at least a score of 3 out of a maximum of 5 points. Logistic regression was performed to identify determinants of full immunization status.
Three hundred and thirty-nine mothers and 339 children (each mother had one eligible child) were included in the survey. Most of the mothers (99.1%) had very positive attitudes to immunization and > 55% were generally knowledgeable about symptoms of vaccine preventable diseases except for difficulty in breathing (as symptom of diphtheria). Two hundred and ninety-five mothers (87.0%) had a satisfactory level of knowledge. Vaccination coverage against all the seven childhood vaccine preventable diseases was 61.9% although it was significantly higher (p = 0.002) amongst those who had a vaccination card (131/188, 69.7%) than in those assessed by maternal history (79/151, 52.3%). Multiple logistic regression showed that mothers' knowledge of immunization (p = 0.006) and vaccination at a privately funded health facility (p < 0.001) were significantly correlated with the rate of full immunization.
Eight years after initiation of this privately financed vaccination project (private-public partnership), vaccination coverage in this rural community is at a level that provides high protection (81%) against DPT/OPV. Completeness of vaccination was significantly correlated with knowledge of mothers on immunization and adequate attention should be given to this if high coverage levels are to be sustained.
Members of the Collaborative Immunization Initiatives determined the immunization coverage rates for two groups of children in our clinic: those 7 to 12 months old and those 18 to 23 months old. The Clinic Assessment Software Application from the Centers for Disease Control and Prevention was used. The immunization rates determined by this method appeared to significantly underestimate the vaccination coverage rates in our clinic. A review of available charts included in the original sample was done excluding patients no longer attending our clinic. We found a higher rate of coverage in the same sample and a low rate of missed opportunities for administering immunizations. The major reason for this discrepancy is overly stringent Clinic Assessment Software Application inclusion criteria. Additional factors include failure to take into account the wide range of acceptable ages for administering immunizations and different dosages for different brands of vaccines. Different methods of calculation may cause as much as a 20% difference in immunization rates for the same or similar population groups. Such large differences may lead to vastly different responses and interventions. We believe that a central registry is the most accurate method of determining immunization rates. Until this is widely available and applied, a more accurate measure of a facility’s immunization effectiveness is the number of missed opportunities for administering immunizations.
Immunization; Immunization Programs; Immunization Rates; Patient Participation Rates; Registries; Vaccination
Neonatal immunization with hepatitis B (HB) vaccine induces protective levels of antibody (anti-HBs ≥10 IU/L) in a majority of vaccines. However, the duration of protection after HB vaccination in infants is unknown. A smaller proportion of children vaccinated beginning at birth with three doses of HB vaccine were found to have protective titers 5–10 years after initial vaccination. Long-term efficacy of HB vaccine depends mainly on peak antibody levels after vaccination, and subjects were observed to have lower levels of antibodies if they received the first dose of vaccine immediately after birth. The aim of our study was to compare the immunogenicity of two different HB vaccine schedules in infants born to HB surface antigen-negative mothers.
Anti-HBs titers in infants vaccinated with two different schedules were compared. Infants were vaccinated at 0, 2, and 9 months (group 1) or at 2, 4, and 9 months (group 2). In total, 267 blood samples were analyzed at a mean of 14.20 ± 2.39 months after the third vaccine dose. Sera were tested for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis B core antibody (anti-HBc) using commercial enzyme immunoassay kits.
The geometric mean titers for anti-HBs were 95.00 and 379.51 IU/L and the rates of anti-HBs more than ≥100 IU/L were 57.7 and 94.9% in group 1 and 2 infants, respectively.
Delaying the first dose of the HB vaccine until 2 months after birth produces a higher immune response and can provide longer term protection.
Hepatitis B vaccine; Immunity duration; Immunogenicity; Schedules
Intermittent preventive treatment (IPTi) with sulphadoxine-pyrimethamine (SP) in infants resulted in different estimates of clinical malaria protection in two trials that used the same protocol in Ifakara, Tanzania, and Manhiça, Mozambique. Understanding the reasons for the discrepant results will help to elucidate the action mechanism of this intervention, which is essential for rational policy formulation.
A comparative analysis of two IPTi trials that used the same study design, follow-up, intervention, procedures and assessment of outcomes, in Tanzania and Mozambique was undertaken. Children were randomised to receive either SP or placebo administered 3 times alongside routine vaccinations delivered through the Expanded Program on Immunisation (EPI). Characteristics of the two areas and efficacy on clinical malaria after each dose were compared.
The most relevant difference was in ITN's use ; 68% in Ifakara and zero in Manhiça. In Ifakara, IPTi was associated with a 53% (95% CI 14.0; 74.1) reduction in the risk of clinical malaria between the second and the third dose; during the same period there was no significant effect in Manhiça. Similarly, protection against malaria episodes was maintained in Ifakara during 6 months after dose 3, but no effect of IPTi was observed in Manhiça.
The high ITN coverage in Ifakara is the most likely explanation for the difference in IPTi efficacy on clinical malaria. Combination of IPTi and ITNs may be the most cost-effective tool for malaria control currently available, and needs to be explored in current and future studies.
Manhiça study registration number: NCT00209795
Ifakara study registration number: NCT88523834
A village-randomized trial of a seven-valent pneumococcal-conjugate-vaccine (PCV-7) conducted in rural Gambia showed a decrease of vaccine-type (VT) and a non-significant increase in non-vaccine-type (NVT) nasopharyngeal carriage of pneumococci two years after vaccination. Here, we report findings four years after vaccination.
PCV-7 was given to all children below 30 months of age enrolled in the trial and to those born during its course in all study villages. Villages were randomized (older children and adults) to receive PCV-7 (wholly vaccinated villages) or serogroup-C-meningococcal-conjugate-vaccine (partly vaccinated villages). Cross-sectional surveys (CSS) to collect nasopharyngeal swabs were conducted before and at various intervals after vaccination. Sixteen of these randomized villages (8 wholly vaccinated and 8 partly vaccinated) participated in a CSS conducted four years after vaccination started.
Four years after vaccination, the prevalence of VT pneumococcal carriage was slightly higher in partly than in wholly vaccinated villages [6.4% versus 3.9% (p = 0.120)] compared to 24.4% in the pre-vaccination CSS (p<0.001). Prevalence of NVT four years after vaccination was similar between study groups [32.7% versus 29.8% (p = 0.392), respectively] compared to 51.1% in the pre-vaccination CSS (p<0.001). Four years after vaccination started, lower prevalence of serotype 6A was detected in wholly vaccinated than in partly vaccinated villages (1.6% versus 3.5%, p = 0.093) whilst the prevalence of serotype 19A was similar between groups (2.9% versus 2.5%, p = 0.779). The most prevalent serotype 19A clone was ST 847. The most prevalent serotype 6A clone before vaccination was ST3324 whilst after vaccination ST913 and ST1737 predominated. Fourteen out of 26 STs detected among the serotype 6A isolates were new while no new 19A serotype ST was found.
The decline in prevalence of VT pneumococci seen shortly after PCV-7 vaccination was sustained four years later with only a small difference between study arms. No significant serotype replacement was detected.
HBV vaccine was introduced into the Expanded Programme on Immunization (EPI) in Senegal and Cameroon in 2005. We conducted a cross-sectional study in both countries to assess the HBV immune protection among children. All consecutive children under 4 years old, hospitalized for any reason between May 2009 and May 2010, with an immunisation card and a complete HBV vaccination, were tested for anti-HBs and anti-HBc. A total of 242 anti-HBc-negative children (128 in Cameroon and 114 in Senegal) were considered in the analysis. The prevalence of children with anti-HBs ≥10 IU/L was higher in Cameroon with 92% (95% CI: 87%–97%) compared to Senegal with 58% (95% CI: 49%–67%), (p<0.001). The response to vaccination in Senegal was lower in 2006–2007 (43%) than in 2008–2009 (65%), (p = 0.028). Our results, although not based on a representative sample of Senegalese or Cameroonian child populations, reveal a significant problem in vaccine response in Senegal. This response problem extends well beyond hepatitis B: the same children who have not developed an immune response to the HBV vaccine are also at risk for diphtheria, tetanus, pertussis (DTwP) and Haemophilus influenzae type b (Hib). Field biological monitoring should be carried out regularly in resource-poor countries to check quality of the vaccine administered.