Search tips
Search criteria

Results 1-25 (33)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
1.  Plasma Viral Loads During Early HIV-1 Infection Are Similar in Subtype C– and Non-Subtype C–Infected African Seroconverters 
The Journal of Infectious Diseases  2013;207(7):1166-1170.
Recent data suggest that infection with human immunodeficiency virus type 1 (HIV-1) subtype C results in prolonged high-level viremia (>5 log10 copies/mL) during early infection. We examined the relationship between HIV-1 subtype and plasma viremia among 153 African seroconverters. Mean setpoint viral loads were similar for C and non-C subtypes: 4.36 vs 4.42 log10 copies/mL (P = .61). The proportion of subtype C–infected participants with viral loads >5 log10 copies/mL was not greater than the proportion for those with non-C infection. Our data do not support the hypothesis that higher early viral load accounts for the rapid spread of HIV-1 subtype C in southern Africa.
PMCID: PMC3583276  PMID: 23315322
HIV-1; group M subtype; plasma viral load; early infection; Africa
2.  Molecular identification, cloning and characterization of transmitted/founder HIV-1 subtype A, D and A/D infectious molecular clones 
Virology  2012;436(1):33-48.
We report the molecular identification, cloning and initial biological characterization of 12 full-length HIV-1 subtype A, D and A/D recombinant transmitted/founder (T/F) genomes. T/F genomes contained intact canonical open reading frames and all T/F viruses were replication competent in primary human T-cells, although subtype D virus replication was more efficient (p<0.05). All 12 viruses utilized CCR5 but not CXCR4 as a co-receptor for entry and exhibited a neutralization profile typical of tier 2 primary virus strains, with significant differences observed between subtype A and D viruses with respect to sensitivity to monoclonal antibodies VRC01, PG9 and PG16 and polyclonal subtype C anti-HIV IgG (p<0.05 for each). The present report doubles the number of T/F HIV-1 clones available for pathogenesis and vaccine research and extends their representation to include subtypes A, B, C and D.
PMCID: PMC3545109  PMID: 23123038
HIV-1; transmitted/founder virus; single genome sequencing; HIV-1 transmission; HIV-1 subtype A; HIV-1 subtype D; neutralizing antibodies
3.  A gp41-Based Heteroduplex Mobility Assay Provides Rapid and Accurate Assessment of Intrasubtype Epidemiological Linkage in HIV Type 1 Heterosexual Transmission Pairs 
AIDS Research and Human Retroviruses  2012;28(12):1745-1755.
A critical step in HIV-1 transmission studies is the rapid and accurate identification of epidemiologically linked transmission pairs. To date, this has been accomplished by comparison of polymerase chain reaction (PCR)-amplified nucleotide sequences from potential transmission pairs, which can be cost-prohibitive for use in resource-limited settings. Here we describe a rapid, cost-effective approach to determine transmission linkage based on the heteroduplex mobility assay (HMA), and validate this approach by comparison to nucleotide sequencing. A total of 102 HIV-1-infected Zambian and Rwandan couples, with known linkage, were analyzed by gp41-HMA. A 400-base pair fragment within the envelope gp41 region of the HIV proviral genome was PCR amplified and HMA was applied to both partners' amplicons separately (autologous) and as a mixture (heterologous). If the diversity between gp41 sequences was low (<5%), a homoduplex was observed upon gel electrophoresis and the transmission was characterized as having occurred between partners (linked). If a new heteroduplex formed, within the heterologous migration, the transmission was determined to be unlinked. Initial blind validation of gp-41 HMA demonstrated 90% concordance between HMA and sequencing with 100% concordance in the case of linked transmissions. Following validation, 25 newly infected partners in Kigali and 12 in Lusaka were evaluated prospectively using both HMA and nucleotide sequences. Concordant results were obtained in all but one case (97.3%). The gp41-HMA technique is a reliable and feasible tool to detect linked transmissions in the field. All identified unlinked results should be confirmed by sequence analyses.
PMCID: PMC3505061  PMID: 22587371
4.  HLA-B*57 versus HLA-B*81 in HIV-1 Infection: Slow and Steady Wins the Race? 
Journal of Virology  2013;87(7):4043-4051.
Two human leukocyte antigen (HLA) variants, HLA-B*57 and -B*81, are consistently known as favorable host factors in human immunodeficiency virus type 1 (HIV-1)-infected Africans and African-Americans. In our analyses of prospective data from 538 recent HIV-1 seroconverters and cross-sectional data from 292 subjects with unknown duration of infection, HLA-B*57 (mostly B*57:03) and -B*81 (exclusively B*81:01) had mostly discordant associations with virologic and immunologic manifestations before antiretroviral therapy. Specifically, relatively low viral load (VL) in HLA-B*57-positive subjects (P ≤ 0.03 in various models) did not translate to early advantage in CD4+ T-cell (CD4) counts (P ≥ 0.37). In contrast, individuals with HLA-B*81 showed little deviation from the normal set point VL (P > 0.18) while maintaining high CD4 count during early and chronic infection (P = 0.01). These observations suggest that discordance between VL and CD4 count can occur in the presence of certain HLA alleles and that effective control of HIV-1 viremia is not always a prerequisite for favorable prognosis (delayed immunodeficiency). Of note, steady CD4 count associated with HLA-B*81 in HIV-1-infected Africans may depend on the country of origin, as observations differed slightly between subgroups enrolled in southern Africa (Zambia) and eastern Africa (Kenya, Rwanda, and Uganda).
PMCID: PMC3624227  PMID: 23365442
5.  Low Primary and Secondary HIV Drug-Resistance after 12 Months of Antiretroviral Therapy in Human Immune-Deficiency Virus Type 1 (HIV-1)-Infected Individuals from Kigali, Rwanda 
PLoS ONE  2013;8(8):e64345.
Treatment outcomes of HIV patients receiving antiretroviral therapy (ART) in Rwanda are scarcely documented. HIV viral load (VL) and HIV drug-resistance (HIVDR) outcomes at month 12 were determined in a prospective cohort study of antiretroviral–naïve HIV patients initiating first-line therapy in Kigali. Treatment response was monitored clinically and by regular CD4 counts and targeted HIV viral load (VL) to confirm drug failure. VL measurements and HIVDR genotyping were performed retrospectively on baseline and month 12 samples. One hundred and fifty-eight participants who completed their month 12 follow-up visit had VL data available at month 12. Most of them (88%) were virologically suppressed (VL≤1000 copies/mL) but 18 had virological failure (11%), which is in the range of WHO-suggested targets for HIVDR prevention. If only CD4 criteria had been used to classify treatment response, 26% of the participants would have been misclassified as treatment failure. Pre-therapy HIVDR was documented in 4 of 109 participants (3.6%) with an HIVDR genotyping results at baseline. Eight of 12 participants (66.7%) with virological failure and HIVDR genotyping results at month 12 were found to harbor mutation(s), mostly NNRTI resistance mutations, whereas 4 patients had no HIVDR mutations. Almost half (44%) of the participants initiated ART at CD4 count ≤200cell/µl and severe CD4 depletion at baseline (<50 cells/µl) was associated with virological treatment failure (p = 0.008).
Although the findings may not be generalizable to all HIV patients in Rwanda, our data suggest that first-line ART regimen changes are currently not warranted. However, the accumulation of acquired HIVDR mutations in some participants underscores the need to reinforce HIVDR prevention strategies, such as increasing the availability and appropriate use of VL testing to monitor ART response, ensuring high quality adherence counseling, and promoting earlier identification of HIV patients and enrollment into HIV care and treatment programs.
PMCID: PMC3741294  PMID: 23950859
6.  Fertility goal-based counseling increases contraceptive implant and IUD use in HIV discordant couples in Rwanda and Zambia 
Contraception  2012;88(1):74-82.
HIV discordant heterosexual couples are faced with the dual challenge of preventing sexual HIV transmission and unplanned pregnancies with the attendant risk of perinatal HIV transmission. Our aim was to examine uptake of two long-acting reversible contraceptive (LARC) methods – intrauterine devices (IUDs) and hormonal implants – among HIV discordant couples in Rwanda and Zambia.
Study Design
Women were interviewed alone or with their partner during routine cohort study follow-up visits to ascertain fertility goals; those not pregnant, not infertile, not already using LARC, and wishing to limit or delay fertility for ≥3 years were counseled on LARC methods and offered an IUD and implant on-site.
Among 409 fertile Rwandan women interviewed (126 alone, 283 with partners), 365 (89%) were counseled about LARC methods and 130 (36%) adopted a method (100 implant, 30 IUD). Of 787 fertile Zambian women interviewed (457 alone, 330 with partners), 528 (67%) received LARC counseling, of whom 177 (34%) adopted a method (139 implant, 38 IUD). In both countries, a woman’s younger age was predictive of LARC uptake. LARC users reported fewer episodes of unprotected sex than couples using only condoms.
Integrated fertility-goal based family planning counseling and access to LARC methods with reinforcement of dual-method use prompted uptake of IUDs and implants and reduced unprotected sex among HIV-discordant couples in two African capital cities.
PMCID: PMC3625675  PMID: 23153896
contraception; family planning; HIV; intrauterine devices; implant
AIDS (London, England)  2012;26(2):217-227.
To identify predictors of promotion of couples’ voluntary counseling and testing (CVCT) in Kigali, Rwanda
Analysis of CVCT promotional agent (influential network leaders, INLs; influential network agents, INAs), and couple/invitation-level predictors of CVCT uptake.
Number of invitations and couples tested were evaluated by INL, INA, and couple/contextual factors. Multivariable logistic regression accounting for two-level clustering analyzed factors predictive of couples’ testing.
26 INLs recruited and mentored 118 INAs who delivered 24,991 invitations. 4,513 couples sought CVCT services after invitation. INAs distributed an average of 212 invitations resulting in an average of 38 couples tested/agent. Characteristics predictive of CVCT in multivariate analyses included the invitee and INA being socially acquainted (aOR=1.4;95%CI:1.2–1.6); invitations delivered after public endorsement (aOR=1.3;95%CI:1.1–1.5); and presence of a mobile testing unit (aOR=1.4;95%CI:1.0–2.0). In stratified analyses, predictors significant among cohabiting couples included invitation delivery to the couple (aOR=1.2;95%CI:1.0–1.4) in the home (aOR=1.3;95%CI:1.1–1.4), while among non-cohabiting couples predictors included invitations given by unemployed INAs (aOR=1.7;95%CI:1.1–2.7). Cohabiting couples with older men were more likely to test, while younger age was associated with testing among men in non-cohabiting unions.
Invitations distributed by influential people were successful in prompting couples to seek joint HIV testing, particularly if the invitation was given in the home to someone known to the INA, and accompanied by a public endorsement of CVCT. Mobile units also increased the number of couples tested. Country-specific strategies to promote CVCT programs are needed to reduce HIV transmission among those at highest risk for HIV in sub-Saharan Africa.
PMCID: PMC3679893  PMID: 22008653
Community Workers; Couples’ Voluntary Counseling and Testing; HIV; Rwanda
8.  Viral Escape from Neutralizing Antibodies in Early Subtype A HIV-1 Infection Drives an Increase in Autologous Neutralization Breadth 
PLoS Pathogens  2013;9(2):e1003173.
Antibodies that neutralize (nAbs) genetically diverse HIV-1 strains have been recovered from a subset of HIV-1 infected subjects during chronic infection. Exact mechanisms that expand the otherwise narrow neutralization capacity observed during early infection are, however, currently undefined. Here we characterized the earliest nAb responses in a subtype A HIV-1 infected Rwandan seroconverter who later developed moderate cross-clade nAb breadth, using (i) envelope (Env) glycoproteins from the transmitted/founder virus and twenty longitudinal nAb escape variants, (ii) longitudinal autologous plasma, and (iii) autologous monoclonal antibodies (mAbs). Initially, nAbs targeted a single region of gp120, which flanked the V3 domain and involved the alpha2 helix. A single amino acid change at one of three positions in this region conferred early escape. One immunoglobulin heavy chain and two light chains recovered from autologous B cells comprised two mAbs, 19.3H-L1 and 19.3H-L3, which neutralized the founder Env along with one or three of the early escape variants carrying these mutations, respectively. Neither mAb neutralized later nAb escape or heterologous Envs. Crystal structures of the antigen-binding fragments (Fabs) revealed flat epitope contact surfaces, where minimal light chain mutation in 19.3H-L3 allowed for additional antigenic interactions. Resistance to mAb neutralization arose in later Envs through alteration of two glycans spatially adjacent to the initial escape signatures. The cross-neutralizing nAbs that ultimately developed failed to target any of the defined V3-proximal changes generated during the first year of infection in this subject. Our data demonstrate that this subject's first recognized nAb epitope elicited strain-specific mAbs, which incrementally acquired autologous breadth, and directed later B cell responses to target distinct portions of Env. This immune re-focusing could have triggered the evolution of cross-clade antibodies and suggests that exposure to a specific sequence of immune escape variants might promote broad humoral responses during HIV-1 infection.
Author Summary
Since cases were first recognized in the United States in 1981, human immunodeficiency virus (HIV-1) has infected over one million Americans. Globally, this scale reaches into the tens of millions, but no effective vaccine exists. Of those infected, approximately 20–30% of patients will develop broadly neutralizing antibodies. The reasons for maturation of these potentially protective responses are presently unknown, but being able to elicit such antibodies via vaccination could curb the pandemic. Here, we defined the earliest neutralizing antibody targets and the consequent routes of viral escape in one subtype A HIV-1 infected subject who developed modest breadth. We also determined the genetic and structural characteristics of early neutralizing monoclonal antibodies circulating in this subject and found that subtle light chain alteration enhanced target contact and neutralization. Overall, our data support the idea that exposure to a specific sequence of viral variants, which have escaped from immune pressure, could program long-term potential for antibody breadth.
PMCID: PMC3585129  PMID: 23468623
9.  Molecular and Phylogeographic Analysis of Human Immuno-deficiency Virus Type 1 Strains Infecting Treatment-naive Patients from Kigali, Rwanda 
PLoS ONE  2012;7(8):e42557.
This study aimed at describing the genetic subtype distribution of HIV-1 strains circulating in Kigali and their epidemiological link with the HIV-1 strains from the five countries surrounding Rwanda. One hundred and thirty eight pol (RT and PR) sequences from 116 chronically- and 22 recently-infected antiretroviral therapy (ART)-naïve patients from Kigali were generated and subjected to HIV drug resistance (HIV-DR), phylogenetic and recombinant analyses in connection with 366 reference pol sequences from Rwanda, Burundi, Kenya, Democratic Republic of Congo, Tanzania and Uganda (Los Alamos database). Among the Rwandan samples, subtype A1 predominated (71.7%), followed by A1/C recombinants (18.1%), subtype C (5.8%), subtype D (2.9%), one A1/D recombinant (0.7%) and one unknown subtype (0.7%). Thirteen unique and three multiple A1/C recombinant forms were identified. No evidence for direct transmission events was found within the Rwandan strains. Molecular characteristics of HIV-1 were similar between chronically and recently-infected individuals and were not significantly associated with demographic or social factors. Our report suggests that the HIV-1 epidemic in Kigali is characterized by the emergence of A1/C recombinants and is not phylogenetically connected with the HIV-1 epidemic in the five neighboring countries. The relatively low level of transmitted HIV-DR mutations (2.9%) reported here indicates the good performance of the ART programme in Rwanda. However, the importance of promoting couples' counseling, testing and disclosure during HIV prevention strategies is highlighted.
PMCID: PMC3419187  PMID: 22905148
10.  Failure of A Novel, Rapid Antigen and Antibody Combination Test to Detect Antigen-Positive HIV Infection in African Adults with Early HIV Infection 
PLoS ONE  2012;7(6):e37154.
Acute HIV infection (prior to antibody seroconversion) represents a high-risk window for HIV transmission. Development of a test to detect acute infection at the point-of-care is urgent.
Volunteers enrolled in a prospective study of HIV incidence in four African cities, Kigali in Rwanda and Ndola, Kitwe and Lusaka in Zambia, were tested regularly for HIV by rapid antibody test and p24 antigen ELISA. Five subgroups of samples were also tested by the Determine Ag/Ab Combo test 1) Antigen positive, antibody negative (acute infection); 2) Antigen positive, antibody positive; 3) Antigen negative, antibody positive; 4) Antigen negative, antibody negative; and 5) Antigen false positive, antibody negative (HIV uninfected). A sixth group included serial dilutions from a p24 antigen-positive control sample. Combo test results were reported as antigen positive, antibody positive, or both.
Of 34 group 1 samples with VL between 5x105 and >1.5x107 copies/mL (median 3.5x106), 1 (2.9%) was detected by the Combo antigen component, 7 (20.6%) others were positive by the Combo antibody component. No group 2 samples were antigen positive by the Combo test (0/18). Sensitivity of the Combo antigen test was therefore 1.9% (1/52, 95% CI 0.0, 9.9). One false positive Combo antibody result (1/30, 3.3%) was observed in group 4. No false-positive Combo antigen results were observed. The Combo antigen test was positive in group 6 at concentrations of 80 pg/mL, faintly positive at 40 and 20 pg/mL, and negative thereafter. The p24 ELISA antigen test remained positive at 5 pg/mL.
Although the antibody component of the Combo test detected antibodies to HIV earlier than the comparison antibody tests used, less than 2% of the cases of antigen-positive HIV infection were detected by the Combo antigen component. The development of a rapid point-of-care test to diagnose acute HIV infection remains an urgent goal.
PMCID: PMC3371037  PMID: 22715363
11.  Performance of the Focus HerpeSelect-2 EIA for the detection of herpes simplex virus type 2 antibodies in seven African countries 
Sexually transmitted infections  2011;87(3):238-241.
To compare the performance of the Focus HerpeSelect-2 enzyme immunoassay (EIA) to the gold standard HSV-2 Western blot, among HIV-1 uninfected men and women in East and Southern Africa.
3399 HIV-1 uninfected women and men from 7 countries in East and Southern Africa were tested for HSV-2 antibody using Focus HerpeSelect-2 EIA. The performance of the HerpesSelect-2 EIA was compared with the gold standard HSV-2 specific Western blot.
Two-thirds (2294/3399) of participants were male and two-thirds (2242/3399) were from East Africa. By Western blot testing, HSV-2 prevalence was 68%, 59% in men and 85% in women. At the manufacturer’s recommended cut-off value of greater than 1.1, the HerpeSelect-2 EIA had a sensitivity of 98.3% and specificity 80.3%. Receiver operating characteristic (ROC) plot analysis indicated that the optimum cut-off was 2.1 or greater with sensitivity 93.9% and specificity 90.5%. Diagnostic accuracy was modestly higher for Southern Africa (AUC=0.979, 95% CI: 0.970-0.988) compared with East Africa (AUC=0.954, 95% CI: 0.942-0.965; p<0.001 for Southern vs. East Africa).
The Focus HerpeSelect-2 EIA has acceptable diagnostic accuracy for determination of HSV-2 serostatus in African HIV-1 uninfected adults. An assay cut-off value of 2.1 or greater results in approximately 90% sensitivity and specificity, against a gold standard HSV-2 Western blot. Diagnostic accuracy differed slightly by geographical region.
PMCID: PMC3066402  PMID: 21307152
HSV-2; Focus HerpeSelect-2 EIA; Western blot; HIV-1; Africa
12.  Differences in HIV Natural History among African and Non-African Seroconverters in Europe and Seroconverters in Sub-Saharan Africa 
PLoS ONE  2012;7(3):e32369.
It is unknown whether HIV treatment guidelines, based on resource-rich country cohorts, are applicable to African populations.
We estimated CD4 cell loss in ART-naïve, AIDS-free individuals using mixed models allowing for random intercept and slope, and time from seroconversion to clinical AIDS, death and antiretroviral therapy (ART) initiation by survival methods. Using CASCADE data from 20 European and 3 sub-Saharan African (SSA) cohorts of heterosexually-infected individuals, aged ≥15 years, infected ≥2000, we compared estimates between non-African Europeans, Africans in Europe, and Africans in SSA.
Of 1,959 (913 non-Africans, 302 Europeans - African origin, 744 SSA), two-thirds were female; median age at seroconversion was 31 years. Individuals in SSA progressed faster to clinical AIDS but not to death or non-TB AIDS. They also initiated ART later than Europeans and at lower CD4 cell counts. In adjusted models, Africans (especially from Europe) had lower CD4 counts at seroconversion and slower CD4 decline than non-African Europeans. Median (95% CI) CD4 count at seroconversion for a 15–29 year old woman was 607 (588–627) (non-African European), 469 (442–497) (European - African origin) and 570 (551–589) (SSA) cells/µL with respective CD4 decline during the first 4 years of 259 (228–289), 155 (110–200), and 199 (174–224) cells/µL (p<0.01).
Despite differences in CD4 cell count evolution, death and non-TB AIDS rates were similar across study groups. It is therefore prudent to apply current ART guidelines from resource-rich countries to African populations.
PMCID: PMC3295758  PMID: 22412867
13.  Human Leukocyte Antigen Variants B*44 and B*57 Are Consistently Favorable during Two Distinct Phases of Primary HIV-1 Infection in Sub-Saharan Africans with Several Viral Subtypes▿† 
Journal of Virology  2011;85(17):8894-8902.
As part of an ongoing study of early human immunodeficiency virus type 1 (HIV-1) infection in sub-Saharan African countries, we have identified 134 seroconverters (SCs) with distinct acute-phase (peak) and early chronic-phase (set-point) viremias. SCs with class I human leukocyte antigen (HLA) variants B*44 and B*57 had much lower peak viral loads (VLs) than SCs without these variants (adjusted linear regression beta values of −1.08 ± 0.26 log10 [mean ± standard error] and −0.83 ± 0.27 log10, respectively; P < 0.005 for both), after accounting for several nongenetic factors, including gender, age at estimated date of infection, duration of infection, and country of origin. These findings were confirmed by alternative models in which major viral subtypes (A1, C, and others) in the same SCs replaced country of origin as a covariate (P ≤ 0.03). Both B*44 and B*57 were also highly favorable (P ≤ 0.03) in analyses of set-point VLs. Moreover, B*44 was associated with relatively high CD4+ T-cell counts during early chronic infection (P = 0.02). Thus, at least two common HLA-B variants showed strong influences on acute-phase as well as early chronic-phase VL, regardless of the infecting viral subtype. If confirmed, the identification of B*44 as another favorable marker in primary HIV-1 infection should help dissect mechanisms of early immune protection against HIV-1 infection.
PMCID: PMC3165830  PMID: 21715491
14.  Transmitted HIV Type 1 Drug Resistance Among Individuals with Recent HIV Infection in East and Southern Africa 
To characterize WHO-defined transmitted HIV drug resistance mutation (TDRM) data from recently HIV-infected African volunteers, we sequenced HIV (pol) and evaluated for TDRM the earliest available specimens from ARV-naive volunteers diagnosed within 1 year of their estimated date of infection at eight research centers in sub-Saharan Africa. TDRMs were detected in 19/408 (5%) volunteers. The prevalence of TDRMs varied by research center, from 5/26 (19%) in Entebbe, 6/78 (8%) in Kigali, 2/49 (4%) in Kilifi, to 3/106 (3%) in Lusaka. One of five volunteers from Cape Town (20%) had TDRMs. Despite small numbers, our data suggest an increase in DRMs by year of infection in Zambia (p = 0.004). The prevalence observed in Entebbe was high across the entire study. ARV history data from 12 (63%) HIV-infected sexual partners were available; 3 reported ARV use prior to transmission. Among four partners with sequence data available, transmission linkage was confirmed and two had the same TDRMs as the newly infected volunteer (both K103N). As ARV therapy continues to increase in availability throughout Africa, monitoring incident virus strains for the presence of TDRMs should be a priority. Early HIV infection cohorts provide an excellent and important platform to monitor the development of TDRMs to inform treatment guidelines, drug choices, and strategies for secondary prevention of TDRM transmission.
PMCID: PMC3045073  PMID: 21091377
15.  Knowledge and Perceptions of Couples' Voluntary Counseling and Testing in Urban Rwanda and Zambia: A Cross-Sectional Household Survey 
PLoS ONE  2011;6(5):e19573.
Most incident HIV infections in sub-Saharan Africa occur between cohabiting, discordant, heterosexual couples. Though couples' voluntary HIV counseling and testing (CVCT) is an effective, well-studied intervention in Africa, <1% of couples have been jointly tested.
We conducted cross-sectional household surveys in Kigali, Rwanda (n = 600) and Lusaka, Zambia (n = 603) to ascertain knowledge, perceptions, and barriers to use of CVCT.
Compared to Lusaka, Kigali respondents were significantly more aware of HIV testing sites (79% vs. 56%); had greater knowledge of HIV serodiscordance between couples (83% vs. 43%); believed CVCT is good (96% vs. 72%); and were willing to test jointly (91% vs. 47%). Stigma, fear of partner reaction, and distance/cost/logistics were CVCT barriers.
Though most respondents had positive attitudes toward CVCT, the majority were unaware that serodiscordance between cohabiting couples is possible. Future messages should target gaps in knowledge about serodiscordance, provide logistical information about CVCT services, and aim to reduce stigma and fear.
PMCID: PMC3090401  PMID: 21573068
16.  Indeterminate and discrepant rapid HIV test results in couples' HIV testing and counselling centres in Africa 
Many HIV voluntary testing and counselling centres in Africa use rapid antibody tests, in parallel or in sequence, to establish same-day HIV status. The interpretation of indeterminate or discrepant results between different rapid tests on one sample poses a challenge. We investigated the use of an algorithm using three serial rapid HIV tests in cohabiting couples to resolve unclear serostatuses.
Heterosexual couples visited the Rwanda Zambia HIV Research Group testing centres in Kigali, Rwanda, and Lusaka, Zambia, to assess HIV infection status. Individuals with unclear HIV rapid antibody test results (indeterminate) or discrepant results were asked to return for repeat testing to resolve HIV status. If either partner of a couple tested positive or indeterminate with the screening test, both partners were tested with a confirmatory test. Individuals with indeterminate or discrepant results were further tested with a tie-breaker and monthly retesting. HIV-RNA viral load was determined when HIV status was not resolved by follow-up rapid testing. Individuals were classified based on two of three initial tests as "Positive", "Negative" or "Other". Follow-up testing and/or HIV-RNA viral load testing determined them as "Infected", "Uninfected" or "Unresolved".
Of 45,820 individuals tested as couples, 2.3% (4.1% of couples) had at least one discrepant or indeterminate rapid result. A total of 65% of those individuals had follow-up testing and of those individuals initially classified as "Negative" by three initial rapid tests, less than 1% were resolved as "Infected". In contrast, of those individuals with at least one discrepant or indeterminate result who were initially classified as "Positive", only 46% were resolved as "Infected", while the remainder was resolved as "Uninfected" (46%) or "Unresolved" (8%). A positive HIV serostatus of one of the partners was a strong predictor of infection in the other partner as 48% of individuals who resolved as "Infected" had an HIV-infected spouse.
In more than 45,000 individuals counselled and tested as couples, only 5% of individuals with indeterminate or discrepant rapid HIV test results were HIV infected. This represented only 0.1% of all individuals tested. Thus, algorithms using screening, confirmatory and tie-breaker rapid tests are reliable with two of three tests negative, but not when two of three tests are positive. False positive antibody tests may persist. HIV-positive partner serostatus should prompt repeat testing.
PMCID: PMC3086828  PMID: 21477317
17.  Affordable in-house antiretroviral drug resistance assay with good performance in non-subtype B HIV-1 
Journal of virological methods  2009;163(2):505-508.
The introduction of antiretroviral therapy in resource-poor settings is effective in suppressing HIV-1 replication and prolonging life of infected individuals. This has led to a demand for affordable HIV-1 drug resistance assays, since treatment failure due to development of drug resistance is common. This study developed and evaluated an affordable “in–house” genotyping assay to monitor HIV-1 drug resistance in Africa, particularly South Africa. An “in-house” assay using automated RNA extraction, and subtype C specific PCR and sequencing primers was developed and successfully evaluated 396 patient samples (viral load ranges 1,000->1.6million RNA copies/ml). The “in-house” assay was validated by comparing sequence data and drug resistance profiles from 90 patient and 10 external quality control samples to data from the ViroSeqTM HIV-1 Genotyping kit. The “in-house” assay was more efficient, amplifying all 100 samples, compared to 91 samples using Viroseq. The “in house” sequences were 99.2%) homologous to the ViroSeq sequences, and identical drug resistance mutation profiles were observed in 96 samples. Furthermore, the “in-house” assay genotyped 260 of 295 samples from seven African sites, where 47% were non-subtype C. Overall, the newly validated “in-house” drug resistance assay is suited for use in Africa as it overcomes the obstacle of subtype diversity.
PMCID: PMC2932961  PMID: 19917318
HIV-1 subtype C; antiretroviral drug resistance; mutation profile; affordable
18.  Safety and Immunogenicity Study of Multiclade HIV-1 Adenoviral Vector Vaccine Alone or as Boost following a Multiclade HIV-1 DNA Vaccine in Africa 
PLoS ONE  2010;5(9):e12873.
We conducted a double-blind, randomized, placebo-controlled Phase I study of a recombinant replication-defective adenovirus type 5 (rAd5) vector expressing HIV-1 Gag and Pol from subtype B and Env from subtypes A, B and C, given alone or as boost following a DNA plasmid vaccine expressing the same HIV-1 proteins plus Nef, in 114 healthy HIV-uninfected African adults.
Methodology/Principal Findings
Volunteers were randomized to 4 groups receiving the rAd5 vaccine intramuscularly at dosage levels of 1×1010 or 1×1011 particle units (PU) either alone or as boost following 3 injections of the DNA vaccine given at 4 mg/dose intramuscularly by needle-free injection using Biojector® 2000. Safety and immunogenicity were evaluated for 12 months. Both vaccines were well-tolerated. Overall, 62% and 86% of vaccine recipients in the rAd5 alone and DNA prime - rAd5 boost groups, respectively, responded to the HIV-1 proteins by an interferon-gamma (IFN-γ) ELISPOT. The frequency of immune responses was independent of rAd5 dosage levels. The highest frequency of responses after rAd5 alone was detected at 6 weeks; after DNA prime - rAd5 boost, at 6 months (end of study). At baseline, neutralizing antibodies against Ad5 were present in 81% of volunteers; the distribution was similar across the 4 groups. Pre-existing immunity to Ad5 did not appear to have a significant impact on reactogenicity or immune response rates to HIV antigens by IFN-γ ELISPOT. Binding antibodies against Env were detected in up to 100% recipients of DNA prime - rAd5 boost. One volunteer acquired HIV infection after the study ended, two years after receipt of rAd5 alone.
The HIV-1 rAd5 vaccine, either alone or as a boost following HIV-1 DNA vaccine, was well-tolerated and immunogenic in African adults. DNA priming increased the frequency and magnitude of cellular and humoral immune responses, but there was no effect of rAd5 dosage on immunogenicity endpoints.
Trial Registration NCT00124007
PMCID: PMC2943475  PMID: 20877623
19.  Knowledge, Use, and Concerns about Contraceptive Methods among Sero-Discordant Couples in Rwanda and Zambia 
Journal of Women's Health  2009;18(9):1449-1456.
The unique needs of sero-discordant couples are largely missing from many current family planning efforts, which focus on the prevention of pregnancies in absence of the reduction of the risk of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). Conversely, HIV testing and programs focus exclusively on condom use without discussion of more effective contraceptive methods. In order to provide information to inform the development of family planning services tailored to the unique needs of sero-discordant couples, this study examined the contraceptive knowledge, use, and concerns among sero-discordant couples in urban Rwanda and Zambia.
This article presents a comparison of family planning knowledge, use, and concerns about contraception among two cohorts of HIV sero-discordant study participants in Rwanda and Zambia.
The results reveal an interesting profile of contraceptive knowledge and use among sero-discordant couples; in both settings, despite high levels of knowledge of contraception, use of contraceptive methods remains relatively low. There is a clear gender difference in both the reporting of knowledge and use of contraceptive methods, and there is evidence of clandestine contraceptive use by women.
Including information on family planning in voluntary counseling and testing (VCT) services in addition to tailoring the delivery of family planning information to meet to needs and concerns of HIV-positive women or those with HIV positive partners is an essential step in the delivery of services and prevention efforts to reduce the transmission of HIV. Family planning and HIV prevention programs should integrate counseling on “dual method use,” combining condoms for HIV/STI prevention with a long-acting contraceptive for added protection against unplanned pregnancy.
PMCID: PMC2825682  PMID: 19708802
20.  Daily Acyclovir Delays HIV-1 Disease Progression Among HIV-1/HSV-2 Dually-Infected Persons: A Randomized Trial 
Lancet  2010;375(9717):824-833.
Well-tolerated medications that slow HIV-1 disease progression and delay initiation of antiretroviral therapy (ART) are needed. Most HIV-1-infected persons are dually-infected with herpes simplex virus type 2 (HSV-2). Daily HSV-2 suppression reduces plasma HIV-1 levels, but whether HSV-2 suppression delays HIV-1 disease progression is unknown.
Within a randomized, placebo-controlled trial of HSV-2 suppressive therapy (acyclovir 400 mg orally bid) to decrease HIV-1 transmission, 3381 HSV-2/HIV-1 dually-infected heterosexual Africans who at enrollment had CD4 counts ≥250 cells/mm3 and were not taking ART were followed for up to 24 months. We evaluated the effect of acyclovir on HIV-1 disease progression, defined by a primary composite endpoint of first occurrence of CD4 count <200 cells/mm3, ART initiation, or non-trauma related death. As an exploratory analysis, we evaluated the endpoint of CD4 decline to <350 cells/mm3.
At enrollment, median CD4 was 462 cells/mm3 and median HIV-1 plasma RNA was 4.1 log10 copies/mL. Acyclovir reduced risk of HIV-1 disease progression: 284 participants on acyclovir versus 324 on placebo reached the primary endpoint (hazard ratio [HR] 0.84, 95% confidence interval [CI] 0.71–0.98, p=0.03). Among participants with CD4 counts ≥350 cells/mm3, acyclovir delayed risk of CD4 decline to <350 cells/mm3 (HR 0.81, 95% CI 0.71–0.93, p=0.002).
HSV-2 suppression with acyclovir reduced the risk of HIV-1 disease progression by 16% (95% CI 2–29%). The role of HSV-2 suppression in reducing HIV-1 disease progression prior to ART initiation warrants consideration ( #NCT00194519).
PMCID: PMC2877592  PMID: 20153888
HIV-1 disease progression; HIV-1 discordant couples; HSV-2; genital herpes; herpes suppression; acyclovir; randomized clinical trial
21.  When one can infect two: a reflection on the impact of HIV discordance on child HIV infection 
This is an opinion piece based on data and experience from Rwanda. The authors believe this opinion piece may help improve current programs on prevention of HIV transmission from mother to child in Africa taking into account the prevalence of HIV sero-discordance in couples. The authors recommend that if we want to ensure newborns stay HIV negative, PMTCT protocols should offer a series of HIV tests linked with antenatal visits and the lactation period as well as HIV testing of current sexual partners. Moreover, if the male partner is found to be positive and the woman is negative, programs should provide intensive counseling on the use of condoms. The lives of three individuals have the potential to be changed from HIV testing and counseling. Morally, this cannot be ignored.
PMCID: PMC2984317  PMID: 21120009
Sero-discordant couples; HIV discordance; PMTCT; children; HIV; Rwanda
22.  Acyclovir and Transmission of HIV-1 from Persons Infected with HIV-1 and HSV-2 
The New England journal of medicine  2010;362(5):427-439.
Most persons who are infected with human immunodeficiency virus type 1 (HIV-1) are also infected with herpes simplex virus type 2 (HSV-2), which is frequently reactivated and is associated with increased plasma and genital levels of HIV-1. Therapy to suppress HSV-2 reduces the frequency of reactivation of HSV-2 as well as HIV-1 levels, suggesting that suppression of HSV-2 may reduce the risk of transmission of HIV-1.
We conducted a randomized, placebo-controlled trial of suppressive therapy for HSV-2 (acyclovir at a dose of 400 mg orally twice daily) in couples in which only one of the partners was seropositive for HIV-1 (CD4 count, ≥250 cells per cubic millimeter) and that partner was also infected with HSV-2 and was not taking antiretroviral therapy at the time of enrollment. The primary end point was transmission of HIV-1 to the partner who was not initially infected with HIV-1; linkage of transmissions was assessed by means of genetic sequencing of viruses.
A total of 3408 couples were enrolled at 14 sites in Africa. Of the partners who were infected with HIV-1, 68% were women, and the baseline median CD4 count was 462 cells per cubic millimeter. Of 132 HIV-1 seroconversions that occurred after randomization (an incidence of 2.7 per 100 person-years), 84 were linked within couples by viral sequencing: 41 in the acyclovir group and 43 in the placebo group (hazard ratio with acyclovir, 0.92, 95% confidence interval [CI], 0.60 to 1.41; P = 0.69). Suppression with acyclovir reduced the mean plasma concentration of HIV-1 by 0.25 log10 copies per milliliter (95% CI, 0.22 to 0.29; P<0.001) and the occurrence of HSV-2–positive genital ulcers by 73% (risk ratio, 0.27; 95% CI, 0.20 to 0.36; P<0.001). A total of 92% of the partners infected with HIV-1 and 84% of the partners not infected with HIV-1 remained in the study for 24 months. The level of adherence to the dispensed study drug was 96%. No serious adverse events related to acyclovir were observed.
Daily acyclovir therapy did not reduce the risk of transmission of HIV-1, despite a reduction in plasma HIV-1 RNA of 0.25 log10 copies per milliliter and a 73% reduction in the occurrence of genital ulcers due to HSV-2. ( number, NCT00194519.)
PMCID: PMC2838503  PMID: 20089951
23.  Couples' voluntary counselling and testing and nevirapine use in antenatal clinics in two African capitals: a prospective cohort study 
With the accessibility of prevention of mother to child transmission (PMTCT) services in sub-Saharan Africa, more women are being tested for HIV in antenatal care settings. Involving partners in the counselling and testing process could help prevent horizontal and vertical transmission of HIV. This study was conducted to assess the feasibility of couples' voluntary counseling and testing (CVCT) in antenatal care and to measure compliance with PMTCT.
A prospective cohort study was conducted over eight months at two public antenatal clinics in Kigali, Rwanda, and Lusaka, Zambia. A convenience sample of 3625 pregnant women was enrolled. Of these, 1054 women were lost to follow up. The intervention consisted of same-day individual voluntary counselling and testing (VCT) and weekend CVCT; HIV-positive participants received nevirapine tablets. In Kigali, nevirapine syrup was provided in the labour and delivery ward; in Lusaka, nevirapine syrup was supplied in pre-measured single-dose syringes. The main outcome measures were nurse midwife-recorded deliveries and reported nevirapine use.
In eight months, 1940 women enrolled in Kigali (984 VCT, 956 CVCT) and 1685 women enrolled in Lusaka (1022 VCT, 663 CVCT). HIV prevalence was 14% in Kigali, and 27% in Lusaka. Loss to follow up was more common in Kigali than Lusaka (33% vs. 24%, p = 0.000). In Lusaka, HIV-positive and HIV-negative women had significantly different loss-to-follow-up rates (30% vs. 22%, p = 0.002). CVCT was associated with reduced loss to follow up: in Kigali, 31% of couples versus 36% of women testing alone (p = 0.011); and in Lusaka, 22% of couples versus 25% of women testing alone (p = 0.137). Among HIV-positive women with follow up, CVCT had no impact on nevirapine use (86-89% in Kigali; 78-79% in Lusaka).
Weekend CVCT, though new, was feasible in both capital cities. The beneficial impact of CVCT on loss to follow up was significant, while nevirapine compliance was similar in women tested alone or with their partners. Pre-measured nevirapine syrup syringes provided flexibility to HIV-positive mothers in Lusaka, but may have contributed to study loss to follow up. These two prevention interventions remain a challenge, with CVCT still operating without supportive government policy in Zambia.
PMCID: PMC2851580  PMID: 20230628
24.  Human Immunodeficiency Virus Type 1 Elite Neutralizers: Individuals with Broad and Potent Neutralizing Activity Identified by Using a High-Throughput Neutralization Assay together with an Analytical Selection Algorithm▿ † 
Journal of Virology  2009;83(14):7337-7348.
The development of a rapid and efficient system to identify human immunodeficiency virus type 1 (HIV-1)-infected individuals with broad and potent HIV-1-specific neutralizing antibody responses is an important step toward the discovery of critical neutralization targets for rational AIDS vaccine design. In this study, samples from HIV-1-infected volunteers from diverse epidemiological regions were screened for neutralization responses using pseudovirus panels composed of clades A, B, C, and D and circulating recombinant forms (CRFs). Initially, 463 serum and plasma samples from Australia, Rwanda, Uganda, the United Kingdom, and Zambia were screened to explore neutralization patterns and selection ranking algorithms. Samples were identified that neutralized representative isolates from at least four clade/CRF groups with titers above prespecified thresholds and ranked based on a weighted average of their log-transformed neutralization titers. Linear regression methods selected a five-pseudovirus subset, representing clades A, B, and C and one CRF01_AE, that could identify top-ranking samples with 50% inhibitory concentration (IC50) neutralization titers of ≥100 to multiple isolates within at least four clade groups. This reduced panel was then used to screen 1,234 new samples from the Ivory Coast, Kenya, South Africa, Thailand, and the United States, and 1% were identified as elite neutralizers. Elite activity is defined as the ability to neutralize, on average, more than one pseudovirus at an IC50 titer of 300 within a clade group and across at least four clade groups. These elite neutralizers provide promising starting material for the isolation of broadly neutralizing monoclonal antibodies to assist in HIV-1 vaccine design.
PMCID: PMC2704778  PMID: 19439467
25.  Characteristics of HIV-1 Discordant Couples Enrolled in a Trial of HSV-2 Suppression to Reduce HIV-1 Transmission: The Partners Study 
PLoS ONE  2009;4(4):e5272.
The Partners HSV-2/HIV-1 Transmission Study (Partners Study) is a phase III, placebo-controlled trial of daily acyclovir for genital herpes (HSV-2) suppression among HIV-1/HSV-2 co-infected persons to reduce HIV-1 transmission to their HIV-1 susceptible partners, which requires recruitment of HIV-1 serodiscordant heterosexual couples. We describe the baseline characteristics of this cohort.
HIV-1 serodiscordant heterosexual couples, in which the HIV-1 infected partner was HSV-2 seropositive, had a CD4 count ≥250 cells/mcL and was not on antiretroviral therapy, were enrolled at 14 sites in East and Southern Africa. Demographic, behavioral, clinical and laboratory characteristics were assessed.
Of the 3408 HIV-1 serodiscordant couples enrolled, 67% of the HIV-1 infected partners were women. Couples had cohabitated for a median of 5 years (range 2–9) with 28% reporting unprotected sex in the month prior to enrollment. Among HIV-1 susceptible participants, 86% of women and 59% of men were HSV-2 seropositive. Other laboratory-diagnosed sexually transmitted infections were uncommon (<5%), except for Trichomonas vaginalis in 14% of HIV-1 infected women. Median baseline CD4 count for HIV-1 infected participants was 462cells/mcL and median HIV-1 plasma RNA was 4.2 log10 copies/mL. After adjusting for age and African region, correlates of HIV-1 RNA level included male gender (+0.24 log10 copies/mL; p<0.001) and CD4 count (−0.25 and −0.55 log10 copies/mL for CD4 350–499 and >500 relative to <350, respectively, p<0.001).
The Partners Study successfully enrolled a cohort of 3408 heterosexual HIV-1 serodiscordant couples in Africa at high risk for HIV-1 transmission. Follow-up of this cohort will evaluate the efficacy of acyclovir for HSV-2 suppression in preventing HIV-1 transmission and provide insights into biological and behavioral factors determining heterosexual HIV-1 transmission.
Trial Registration NCT00194519
PMCID: PMC2671170  PMID: 19404392

Results 1-25 (33)