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1.  Determinants of Per-Coital-Act HIV-1 Infectivity Among African HIV-1–Serodiscordant Couples 
The Journal of Infectious Diseases  2012;205(3):358-365.
(See the editorial commentary by Gray and Wawer on pages 351–2.)
Background. Knowledge of factors that affect per-act infectivity of human immunodeficiency virus type 1 (HIV-1) is important for designing HIV-1 prevention interventions and for the mathematical modeling of the spread of HIV-1.
Methods. We analyzed data from a prospective study of African HIV-1–serodiscordant couples. We assessed transmissions for linkage within the study partnership, based on HIV-1 sequencing. The primary exposure measure was the HIV-1–seropositive partners’ reports of number of sex acts and condom use with their study partner.
Results. Of 3297 couples experiencing 86 linked HIV-1 transmissions, the unadjusted per-act risks of unprotected male-to-female (MTF) and female-to-male (FTM) transmission were 0.0019 (95% confidence interval [CI], .0010–.0037) and 0.0010 (95% CI, .00060–.0017), respectively. After adjusting for plasma HIV-1 RNA of the HIV-1–infected partner and herpes simplex virus type 2 serostatus and age of the HIV-1–uninfected partner, we calculated the relative risk (RR) for MTF versus FTM transmission to be 1.03 (P = .93). Each log10 increase in plasma HIV-1 RNA increased the per-act risk of transmission by 2.9-fold (95% CI, 2.2–3.8). Self-reported condom use reduced the per-act risk by 78% (RR = 0.22 [95% CI, .11–.42]).
Conclusions. Modifiable risk factors for HIV-1 transmission were plasma HIV-1 RNA level and condom use, and, in HIV-1–uninfected partners, herpes simplex virus 2 infection, genital ulcers, Trichomonas vaginalis, vaginitis or cervicitis, and male circumcision.
doi:10.1093/infdis/jir747
PMCID: PMC3256946  PMID: 22241800
2.  Valacyclovir Suppressive Therapy Reduces Plasma and Breast Milk HIV-1 RNA Levels During Pregnancy and Postpartum: A Randomized Trial 
The Journal of Infectious Diseases  2011;205(3):366-375.
Background. The effect of herpes simplex virus type 2 (HSV-2) suppression on human immunodeficiency virus type 1 (HIV-1) RNA in the context of prevention of mother-to-child transmission (PMTCT) interventions is unknown.
Methods. Between April 2008 and August 2010, we conducted a randomized, double-blind trial of twice daily 500 mg valacyclovir or placebo beginning at 34 weeks gestation in 148 HIV-1/HSV-2 coinfected pregnant Kenyan women ineligible for highly active antiretroviral therapy (CD4 > 250 cells/mm3). Women received zidovudine and single dose nevirapine for PMTCT and were followed until 12 months postpartum.
Results. Mean baseline plasma HIV-1 RNA was 3.88 log10 copies/mL. Mean plasma HIV-1 was lower during pregnancy (−.56 log10 copies/mL; 95% confidence interval [CI], −.77 to −.34) and after 6 weeks postpartum (−.51 log10 copies/mL; 95% CI, −.73 to −.30) in the valacyclovir arm than the placebo arm. Valacyclovir reduced breast milk HIV-1 RNA detection at 6 and 14 weeks postpartum compared with placebo (30% lower, P = .04; 46% lower, P = .01, respectively), but not after 14 weeks. Cervical HIV-1 RNA detection was similar between arms (P = .91).
Conclusions. Valacyclovir significantly decreased early breast milk and plasma HIV-1 RNA among women receiving PMTCT.
Clinical Trials Registration. NCT00530777.
doi:10.1093/infdis/jir766
PMCID: PMC3256951  PMID: 22147786
3.  Breast Milk HIV-1 RNA Levels and Female Sex Are Associated With HIV-1–Specific CD8+ T-Cell Responses in HIV-1–Exposed, Uninfected Infants in Kenya 
The Journal of Infectious Diseases  2011;204(11):1806-1810.
Background. Although evidence supports a relationship between human immunodeficiency virus (HIV)–1 exposure and HIV-1−specific CD8+ T cell responses, studies have not demonstrated a direct association between the quantity of HIV-1 to which a person is exposed and the presence or absence of a response.
Methods. From 1999 to 2005, maternal HIV-1 RNA levels were measured in blood, cervical secretions, and breast milk at delivery and 1 month after delivery. HIV-1−specific interferon (IFN)–γ Elispot assays were conducted to determine infant CD8+ T-cell responses at 3 months of age.
Results. Among 161 infants tested with Elispot assays, 23 (14%) had positive results. Mothers whose infants had a positive assay had higher breast milk HIV-1 RNA levels at month 1 compared with mothers whose infants had negative Elispot assays (3.1 vs 2.5 log10 copies/mL; P = .017). Female infants were also more likely to have positive Elispot assays than male infants (P = .046), and in multivariate analyses, both female sex and high breast milk HIV-1 levels remained important predictors of a positive response (P = .022 and P = .015, respectively).
Conclusions. Exposure to breast milk HIV-1 and sex were associated with development of HIV-1−specific CD8+ T-cell responses in infants. These data support a role for mucosal exposure via the oral route in induction of systemic HIV-1−specific cellular immunity.
doi:10.1093/infdis/jir643
PMCID: PMC3203234  PMID: 21984736
4.  Using Plasma Viral Load to Guide Antiretroviral Therapy Initiation to Prevent HIV-1 Transmission 
PLoS ONE  2012;7(11):e51192.
Background
Current WHO guidelines recommend antiretroviral therapy (ART) initiation at CD4 counts ≤350 cells/µL. Increasing this threshold has been proposed, with a primary goal of reducing HIV-1 infectiousness. Because the quantity of HIV-1 in plasma is the primary predictor of HIV-1 transmission, consideration of plasma viral load in ART initiation guidelines is warranted.
Methods
Using per-sex-act infectivity estimates and cross-sectional sexual behavior data from 2,484 HIV-1 infected persons with CD4 counts >350 enrolled in a study of African heterosexual HIV-1 serodiscordant couples, we calculated the number of transmissions expected and the number potentially averted under selected scenarios for ART initiation: i) CD4 count <500 cells/µL, ii) viral load ≥10,000 or ≥50,000 copies/mL and iii) universal treatment. For each scenario, we estimated the proportion of expected infections that could be averted, the proportion of infected persons initiating treatment, and the ratio of these proportions.
Results
Initiating treatment at viral load ≥50,000 copies/mL would require treating 19.8% of infected persons with CD4 counts >350 while averting 40.5% of expected transmissions (ratio 2.0); treating at viral load ≥10,0000 copies/mL had a ratio of 1.5. In contrast, initiation at CD4 count <500 would require treating 41.8%, while averting 48.4% (ratio 1.1).
Conclusion
Inclusion of viral load in ART initiation guidelines could permit targeting ART resources to HIV-1 infected persons who have a higher risk of transmitting HIV-1. Further work is needed to estimate costs and feasibility.
doi:10.1371/journal.pone.0051192
PMCID: PMC3511400  PMID: 23250272
5.  Barriers to Antiretroviral Initiation in HIV-1-Discordant Couples 
BACKGROUND
In Kenya and much of sub-Saharan Africa, nearly half of all couples affected by HIV are discordant. Antiretroviral therapy (ART) slows disease progression in HIV-1-infected individuals, and reduces transmission to uninfected partners. We examined time to ART initiation and factors associated with delayed initiation in HIV-1-discordant couples in Nairobi.
METHODS
HIV-1-discordant couples were enrolled and followed quarterly for up to 2 years. Clinical staff administered questionnaires and conducted viral loads and CD4 counts. Participants with a CD4 count meeting ART criteria were referred to a nearby PEPFAR-funded treatment center. Barriers to ART initiation among participants with a CD4 count eligible for ART were assessed by Cox regression.
RESULTS
Of 439 HIV-1-infected participants (63.6% females and 36.4% males) 146 met CD4 count criteria for ART during follow-up. Median time from meeting CD4 criteria until ART initiation was 8.9 months, with 42.0% of eligible participants on ART by 6 months and 63.4% on ART by 1 year. The CD4 count at the time of eligibility was inversely associated with time to ART initiation (HR=0.49, p< 0.001). Compared to homeowners, those paying higher rents started ART 48% more slowly (p=0.062) and those paying lower rents started 71% more slowly (p=0.002).
CONCLUSIONS
Despite access to regular health care, referrals to treatment centers, and free access to ART, over a third of participants with an eligible CD4 count had not started ART within 1 year. Factors of lower socioeconomic status may slow ART initiation and targeted approaches are needed to avoid delays in treatment initiation.
doi:10.1097/QAI.0b013e31822f064e
PMCID: PMC3202340  PMID: 21826010
HIV; discordant couples; serodiscordant; antiretroviral; ART; HAART
6.  Distance from Home to Study Clinic and Risk of Follow-Up Interruption in a Cohort of HIV-1-Discordant Couples in Nairobi, Kenya 
PLoS ONE  2012;7(8):e43138.
Background
Longitudinal studies of HIV-1-infected individuals or those at risk of infection are subject to missed study visits that may have negative consequences on the care of participants and can jeopardize study validity due to bias and loss of statistical power. Distance between participant residence and study clinic, as well as other socioeconomic and demographic factors, may contribute to interruptions in patient follow-up.
Methods
HIV-1-serodiscordant couples were enrolled between May 2007 and October 2009 and followed for two years in Nairobi, Kenya. At baseline, demographic and home location information was collected and linear distance from each participant’s home to the study clinic was determined. Participants were asked to return to the study clinic for quarterly visits, with follow-up interruptions (FUI) defined as missing two consecutive visits. Cox proportional hazards regression was used to assess crude and adjusted associations between FUI and home-to-clinic distance, and other baseline characteristics.
Results
Of 469 enrolled couples, 64% had a female HIV-1-infected partner. Overall incidence of FUI was 13.4 per 100 person-years (PY), with lower incidence of FUI in HIV-1-infected (10.8 per 100 PY) versus -uninfected individuals (16.1 per 100 PY) (hazard ratio [HR] = 0.66; 95% confidence interval [CI]: 0.50, 0.88). Among HIV-1-infected participants, those living between 5 and 10 kilometers (km) from the study clinic had a two-fold increased rate of FUI compared to those living <5 km away (HR = 2.17; 95% CI: 1.09, 4.34). Other factors associated with FUI included paying higher rent (HR = 1.67; 95% CI: 1.05, 2.65), having at least primary school education (HR = 1.96; 95% CI: 1.02, 3.70), and increased HIV-1 viral load (HR = 1.23 per log10 increase; 95% CI: 1.01, 1.51).
Conclusions
Home-to-clinic distance, indicators of socioeconomic status, and markers of disease progression may affect compliance with study follow-up schedules. Retention strategies should focus on participants at greatest risk of FUI to ensure study validity.
doi:10.1371/journal.pone.0043138
PMCID: PMC3428010  PMID: 22937017
7.  Maternal Human Leukocyte Antigen - A*2301 Is Associated with Increased Mother-to-Child HIV-1 Transmission 
The Journal of infectious diseases  2010;202(8):1273-1277.
We examined associations between maternal HLA and vertical HIV-1 transmission in a perinatal cohort of 277 HIV-infected women in Nairobi. HLA class I genes were amplified using sequence-specific oligonucleotide probes and analyses were performed using logistic regression. Maternal A*2301 was associated with increased transmission risk before and after adjusting for maternal viral load (odds ratio [OR]=3.21; 95% CI: 1.42, 7.27, p=0.005, pcorr=0.04; adjusted OR=3.07; 95% CI: 1.26, 7.51, p=0.01, pcorr=NS). That maternal HLA-A*2301 was associated with transmission independent of plasma HIV-1 RNA levels, suggests that HLA may alter infectivity through mechanisms other than influencing HIV-1 viral load.
doi:10.1086/656318
PMCID: PMC3404885  PMID: 20812845
Human immunodeficiency virus; vertical HIV-1 transmission; human leukocyte antigen
8.  Establishing and Sustaining a Healthy Vaginal Environment: Analysis of Data From a Randomized Trial of Periodic Presumptive Treatment for Vaginal Infections 
The Journal of Infectious Diseases  2011;204(2):323-326.
Data from a randomized trial of oral periodic presumptive treatment (PPT) to reduce vaginal infections were analyzed to assess the effect of the intervention on a healthy vaginal environment (normal flora confirmed by Gram stain with no candidiasis or trichomoniasis). The incidence of a healthy vaginal environment was 608 cases per 100 person-years in the intervention arm and 454 cases per 100 person-years in the placebo arm (hazard ratio [HR], 1.36; 95% confidence interval [CI], 1.17–1.58). Sustained vaginal health (healthy vaginal environment for ≥3 consecutive visits) was also more frequent in the intervention arm (HR, 1.69; 95% CI, 1.23–2.33). PPT is effective at establishing and sustaining a healthy vaginal environment.
doi:10.1093/infdis/jir241
PMCID: PMC3114467  PMID: 21673045
9.  HIV-1 Disease Progression in Breast-Feeding and Formula-Feeding Mothers: A Prospective 2-Year Comparison of T Cell Subsets, HIV-1 RNA Levels, and Mortality 
The Journal of Infectious Diseases  2006;195(2):220-229.
Background
There is conflicting evidence regarding the effects of breast-feeding on maternal mortality from human immunodeficiency virus type 1 (HIV-1) infection, and little is known about the effects of breast-feeding on markers of HIV-1 disease progression.
Methods
HIV-1–seropositive women were enrolled during pregnancy and received short-course zidovudine. HIV-1 RNA levels and CD4 cell counts were determined at baseline and at months 1, 3, 6, 12, 18, and 24 postpartum and were compared between breast-feeding and formula-feeding mothers.
Results
Of 296 women, 98 formula fed and 198 breast-fed. At baseline, formula-feeding women had a higher education level and prevalence of HIV-1–related illness than did breast-feeding women; however, the groups did not differ with respect to CD4 cell counts and HIV-1 RNA levels. Between months 1 and 24 postpartum, CD4 cell counts decreased 3.9 cells/µL/month (P< .001), HIV-1 RNA levels increased 0.005 log10 copies/mL/month (P = .03), and body mass index (BMI) decreased 0.03 kg/m2/month (P< .001). The rate of CD4 cell count decline was higher in breast-feeding mothers (7.2 cells/µL/month) than in mothers who never breast-fed (4.0 cells/µL/month) (P = .01). BMI decreased more rapidly in breast-feeding women (P = .04), whereas HIV-1 RNA levels and mortality did not differ significantly between breast-feeding and formula-feeding women.
Conclusions
Breast-feeding was associated with significant decreases in CD4 cell counts and BMI. HIV-1 RNA levels and mortality were not increased, suggesting a limited adverse impact of breast-feeding in mothers receiving extended care for HIV-1 infection.
doi:10.1086/510245
PMCID: PMC3394541  PMID: 17191167
10.  Knowledge and Acceptability of Pap Smears, Self-Sampling and HPV Vaccination among Adult Women in Kenya 
PLoS ONE  2012;7(7):e40766.
Objectives
Our study aimed to assess adult women’s knowledge of human papillomavirus (HPV) and cervical cancer, and characterize their attitudes towards potential screening and prevention strategies.
Methods
Women were participants of an HIV-discordant couples cohort in Nairobi, Kenya. An interviewer-administered questionnaire was used to obtain information on sociodemographic status, and sexual and medical history at baseline and on knowledge and attitudes towards Pap smears, self-sampling, and HPV vaccination at study exit.
Results
Only 14% of the 409 women (67% HIV-positive; median age 29 years) had ever had a Pap smear prior to study enrollment and very few women had ever heard of HPV (18%). Although most women knew that Pap smears detect cervical cancer (69%), very few knew that routine Pap screening is the main way to prevent ICC (18%). Most women reported a high level of cultural acceptability for Pap smear screening and a low level of physical discomfort during Pap smear collection. In addition, over 80% of women reported that they would feel comfortable using a self-sampling device (82%) and would prefer at-home sample collection (84%). Nearly all women (94%) reported willingness to be vaccinated to prevent cervical cancer if offered at no or low cost.
Conclusions
These findings highlight the need to educate women on routine use of Pap smears in the prevention of cervical cancer and demonstrate that vaccination and self-sampling would be acceptable modalities for cervical cancer prevention and screening.
doi:10.1371/journal.pone.0040766
PMCID: PMC3393696  PMID: 22808257
11.  High Uptake of Postpartum Hormonal Contraception Among HIV-1-Seropositive Women in Kenya 
Sexually Transmitted Diseases  2007;34(1):25-29.
Objectives
The objectives of this study were to determine patterns of contraceptive utilization among sexually active HIV-1-seropositive women postpartum and to identify correlates of hormonal contraception uptake.
Goal
The goal of this study was to improve delivery of family planning services to HIV-1-infected women in resource-limited settings.
Study Design
HIV-1-infected pregnant women were followed prospectively in a perinatal HIV-1 transmission study. Participants were referred to local clinics for contraceptive counseling and management.
Results
Among 319 HIV-1-infected women, median time to sexual activity postpartum was 2 months and 231 (72%) women used hormonal contraception for at least 2 months during follow-up, initiating use at approximately 3 months postpartum (range, 1–11 months). Overall, 101 (44%) used DMPA, 71 (31%) oral contraception, and 59 (25%) switched methods during follow-up. Partner notification, infant mortality, and condom use were similar between those using and not using contraception.
Conclusions
Using existing the healthcare infrastructure, it is possible to achieve high levels of postpartum hormonal contraceptive utilization among HIV-1-seropositive women.
doi:10.1097/01.olq.0000218880.88179.36
PMCID: PMC3387272  PMID: 16691159
12.  Antenatal Couple Counseling Increases Uptake of Interventions to Prevent HIV-1 Transmission 
Summary
To determine effect of partner involvement and couple counseling on uptake of interventions to prevent HIV-1 transmission, women attending a Nairobi antenatal clinic were encouraged to return with partners for voluntary HIV-1 counseling and testing (VCT) and offered individual or couple posttest counseling. Nevirapine was provided to HIV-1-seropositive women and condoms distributed to all participants. Among 2104 women accepting testing, 308 (15%) had partners participate in VCT, of whom 116 (38%) were couple counseled. Thirty-two (10%) of 314 HIV-1-seropositive women came with partners for VCT; these women were 3-fold more likely to return for nevirapine (P = 0.02) and to report administering nevirapine at delivery (P = 0.009). Nevirapine use was reported by 88% of HIV-infected women who were couple counseled, 67% whose partners came but were not couple counseled, and 45% whose partners did not present for VCT (P for trend = 0.006). HIV-1-seropositive women receiving couple counseling were 5-fold more likely to avoid breast-feeding (P = 0.03) compared with those counseled individually. Partner notification of HIV-1-positive results was reported by 138 women (64%) and was associated with 4-fold greater likelihood of condom use (P = 0.004). Partner participation in VCT and couple counseling increased uptake of nevirapine and formula feeding. Antenatal couple counseling may be a useful strategy to promote HIV-1 prevention interventions.
PMCID: PMC3384734  PMID: 15577420
voluntary counseling and testing; couple counseling; mother-to-child HIV-1 transmission; breastfeeding; nevirapine; condom use; partner notification
13.  Domestic violence and prevention of mother-to-child transmission of HIV-1 
AIDS (London, England)  2006;20(13):1763-1769.
Objectives
To determine the prevalence of life-time domestic violence by the current partner before HIV-1 testing, its impact on the uptake of prevention of mother-to-child transmission (PMTCT) interventions and frequency after testing.
Design
A prospective cohort.
Methods
Antenatally, women and their partners were interviewed regarding physical, financial, and psychological abuse by the male partner before HIV-1 testing and 2 weeks after receiving results.
Results
Before testing, 804 of 2836 women (28%) reported previous domestic violence, which tended to be associated with increased odds of HIV-1 infection [univariate odds ratio (OR) 1.7, 95% confidence interval (CI) 1.3–2.2; P < 0.0001, adjusted OR 1.2, 95% CI 0.9–1.6; P = 0.1], decreased odds of coming with partners for counseling (adjusted OR 0.7, 95% CI 0.5–1.0; P = 0.04), and decreased odds of partner notification (adjusted OR 0.7, 95% CI 0.5–1.1; P = 0.09). Previous domestic violence was not associated with a reduced uptake of HIV-1 counseling, HIV-1 testing, or nevirapine. After receiving results, 15 out of 1638 women (0.9%) reported domestic violence. After notifying partners of results, the odds of HIV-1-seropositive women reporting domestic violence were 4.8 times those of HIV-1-seronegative women (95% CI 1.4–16; P = 0.01). Compared with women, men reported similar or more male-perpetrated domestic violence, suggesting a cultural acceptability of violence.
Conclusion
Domestic violence before testing may limit partner involvement in PMTCT. Although infrequent, immediate post-test domestic violence is more common among HIV-1-infected than uninfected women. Domestic violence prevention programmes need to be integrated into PMTCT, particularly for HIV-1-seropositive women.
doi:10.1097/01.aids.0000242823.51754.0c
PMCID: PMC3384736  PMID: 16931941
Adverse effects; Africa; domestic violence; HIV; vertical transmission; prevention of mother-to-child transmission
14.  Longitudinal Comparison of Chemokines in Breastmilk Early Postpartum Among HIV-1-Infected and Uninfected Kenyan Women 
Breastfeeding Medicine  2007;2(3):129-138.
Breastmilk chemokines have been associated with increased HIV-1 RNA levels in breastmilk and altered risk of mother-to-child HIV-1 transmission. To characterize CC and CXC chemokines in breastmilk postpartum, we collected breastmilk specimens at regular intervals for 6 months after delivery from women with and without HIV-1 infection and used commercial ELISA kits to measure breastmilk concentrations of MIP-1α, MIP-1β, RANTES, and SDF-1α. Among 54 HIV-1-infected and 26 uninfected women, mean chemokine levels were compared cross-sectionally and longitudinally at days 5 and 10, and months 1 and 3 postpartum. For both HIV-1-infected and uninfected women, breastmilk chemokine levels were highest at day 5 for MIP-1α, MIP-1β, and SDF-1α, and subsequently decreased. RANTES levels remained constant over the follow-up period among HIV-1-uninfected women, and increased moderately among HIV-1-infected women. For MIP-1β and RANTES, breastmilk levels were significantly higher among HIV-1-infected women compared to uninfected women early postpartum. In addition, HIV-1-infected women transmitting HIV-1 to their infant had consistently higher breastmilk RANTES levels than those who did not transmit, with the greatest difference observed at 1 month (2.68 vs. 2.21 log10 pg/mL, respectively; p = 0.007). In summary, all four chemokines were most elevated within the first month postpartum, a period of high transmission risk via breastmilk. MIP-1β and RANTES levels in breastmilk were higher among HIV-1-infected women than among uninfected women, and breastmilk RANTES was positively associated with vertical transmission in this study, consistent with results from our earlier cohort.
doi:10.1089/bfm.2007.0009
PMCID: PMC3381953  PMID: 17903098
15.  Salivary Secretory Leukocyte Protease Inhibitor Is Associated with Reduced Transmission of Human Immunodeficiency Virus Type 1 through Breast Milk 
The Journal of Infectious Diseases  2002;186(8):1173-1176.
Secretory leukocyte protease inhibitor (SLPI), a protein found in saliva, breast milk, and genital secretions, is capable of inhibiting human immunodeficiency virus (HIV) type 1 in vitro. The aim of this study was to determine whether SLPI in infant saliva provides protection against mother-to-child HIV-1 transmission. In total, 602 saliva specimens were collected from 188 infants at birth and at ages 1, 3, and 6 months. Infants’ median salivary SLPI concentrations were higher at birth than at 6 months (341 vs. 219 ng/mL; P = .001). There was no association between SLPI concentration and HIV-1 transmission overall. However, among 122 breast-fed infants who were HIV-1 uninfected at 1 month, higher salivary SLPI levels were associated with a decreased risk of HIV-1 transmission through breast milk (hazard ratio, 0.5; 95% confidence interval, 0.3–0.9; P = .03). These results suggest that SLPI plays an important role in reducing HIV-1 transmission through breast milk.
doi:10.1086/343805
PMCID: PMC3382060  PMID: 12355371
16.  High Maternal HIV-1 Viral Load During Pregnancy Is Associated With Reduced Placental Transfer of Measles IgG Antibody 
Background
Studies among HIV-1–infected women have demonstrated reduced placental transfer of IgG antibodies against measles and other pathogens. As a result, infants born to women with HIV-1 infection may not acquire adequate passive immunity in utero and this could contribute to high infant morbidity and mortality in this vulnerable population.
Methods
To determine factors associated with decreased placental transfer of measles IgG, 55 HIV-1–infected pregnant women who were enrolled in a Nairobi perinatal HIV-1 transmission study were followed. Maternal CD4 count, HIV-1 viral load, and HIV-1–specific gp41 antibody concentrations were measured antenatally and at delivery. Measles IgG concentrations were assayed in maternal blood and infant cord blood obtained during delivery to calculate placental antibody transfer.
Results
Among 40 women (73%) with positive measles titers, 30 (75%) were found to have abnormally low levels of maternofetal IgG transfer (<95%). High maternal HIV-1 viral load at 32 weeks’ gestation and at delivery was associated with reductions in placental transfer (P < 0.0001 and P = 0.0056, respectively) and infant measles IgG concentrations in cord blood (P < 0.0001 and P = 0.0073, respectively). High maternal HIV-1–specific gp41 antibody titer was also highly correlated with both decreased placental transfer (P = 0.0080) and decreased infant IgG (P < 0.0001).
Conclusions
This is the first study to evaluate the relationship between maternal HIV-1 viremia, maternal HIV-1 antibody concentrations, and passive immunity among HIV-1–exposed infants. These data support the hypothesis that high HIV-1 viral load during the last trimester may impair maternofetal transfer of IgG and increases risk of measles and other serious infections among HIV-1–exposed infants.
PMCID: PMC3382062  PMID: 16280707
placental antibody transfer; maternal HIV-1 viral load; measles IgG; HIV-1–specific gp41 antibody; mother-to-child HIV-1 transmission
17.  Pediatric HIV Type 1 Vaccine Trial Acceptability among Mothers in Kenya 
Vaccination of infants against human immunodeficiency virus type 1 (HIV-1) may prevent mother-to-child HIV-1 transmission. Successful trials and immunization efforts will depend on the willingness of individuals to participate in pediatric vaccine research and acceptance of infant HIV-1 vaccines. In a cross-sectional study, pregnant women presenting to a Nairobi antenatal clinic for routine care were interviewed regarding their attitudes toward participation in research studies and HIV-1 vaccine acceptability for their infants. Among 805 women, 782 (97%) reported they would vaccinate their infant against HIV-1 and 729 (91%) reported willingness to enroll their infant in a research study. However, only 644 (80%) would enroll their infants if HIV-1 testing was required every 3 months and 513 (64%) would agree to HIV-1 vaccine trial participation. Reasons for not wanting to enroll in a pediatric HIV-1 vaccine trial included concerns about side effects (75%), partner objection (34%), and fear of discrimination (10%), HIV-1 acquisition (8%), or false-positive HIV-1 results (5%). The strongest correlate of pediatric vaccine trial participation was maternal willingness to be a vaccine trial participant herself; in univariate and multivariate models this was associated with a 17-fold increased likelihood of participation (HR 17.1; 95% CI 11.7–25; p < 0.001). We conclude from these results that immunizing infants against HIV-1 and participation in pediatric vaccine trials are generally acceptable to women at high risk for HIV-1 infection. It will be important to address barriers identified in this study and to include male partners when mobilizing communities for pediatric HIV-1 vaccine trials and immunization programs.
doi:10.1089/aid.2006.22.491
PMCID: PMC3382079  PMID: 16796522
18.  Breast Milk α-Defensins Are Associated with HIV Type 1 RNA and CC Chemokines in Breast Milk But Not Vertical HIV Type 1 Transmission 
α-Defensins are proteins exhibiting in vitro anti-HIV-1 activity that may protect against mother-to-child transmission of HIV-1 via breast milk. Correlates of α-defensins in breast milk and transmission risk were determined in a cohort of HIV-1-infected pregnant women in Nairobi followed for 12 months postpartum with their infants. Maternal blood was collected antenatally and at delivery for HIV-1 viral load and infant HIV-1 infection status was determined <48 h after birth and at months 1, 3, 6, 9, and 12. Breast milk specimens collected at month 1 were assayed for α-defensins, HIV-1 RNA, subclinical mastitis, and CC and CXC chemokines. We detected α-defensins in breast milk specimens from 108 (42%) of 260 HIV-1-infected women. Women with detectable α-defensins (≥50 pg/ml) had a median concentration of 320 pg/ml and significantly higher mean breast milk HIV-1 RNA levels than women with undetectable α-defensins (2.9 log10 copies/ml versus 2.5 log10 copies/ml, p = 0.003). Increased α-defensins concentrations in breast milk were also associated with subclinical mastitis (Na+/K+ ratio > 1) and increased breast milk chemokine levels. Overall, 40 (15%) infants were HIV-1 uninfected at birth and subsequently acquired HIV-1. There was no significant association between month 1 α-defensins and risk of HIV-1 transmission. In conclusion, α-defensins were associated with breast milk HIV-1 viral load, chemokine levels, and subclinical mastitis, all of which may alter risk of infant HIV-1 acquisition. Despite these associations there was no significant relationship between breast milk α-defensins and mother-to-child transmission, suggesting a complex interplay between breast milk HIV-1, inflammation, and antiinfective factors.
doi:10.1089/aid.2006.0125
PMCID: PMC3382116  PMID: 17331027
19.  Early Response to Highly Active Antiretroviral Therapy in HIV-1–Infected Kenyan Children 
Objectives
To describe the early response to World Health Organization (WHO)–recommended nonnucleoside reverse transcriptase inhibitor (NNRTI)–based first-line highly active antiretroviral therapy (HAART) in HIV-1–infected Kenyan children unexposed to nevirapine.
Design
Observational prospective cohort.
Methods
HIV-1 RNA level, CD4 lymphocyte count, weight for age z score, and height for age z score were measured before the initiation of HAART and every 3 to 6 months thereafter. Children received no nutritional supplements.
Results
Sixty-seven HIV-1–infected children were followed for a median of 9 months between August 2004 and November 2005. Forty-seven (70%) used zidovudine, lamivudine (3TC), and an NNRTI (nevirapine or efavirenz), whereas 25% used stavudine (d4T), 3TC, and an NNRTI. Nevirapine was used as the NNRTI by 46 (69%) children, and individual antiretroviral drug formulations were used by 63 (94%), with only 4 (6%) using a fixed-dose combination of d4T, 3TC, and nevirapine (Triomune; Cipla, Mumbai, India). In 52 children, the median height for age z score and weight for age z score rose from −2.54 to −2.17 (P < 0.001) and from −2.30 to −1.67 (P = 0.001), respectively, after 6 months of HAART. Hospitalization rates were significantly reduced after 6 months of HAART (17% vs. 58%; P < 0.001). The median absolute CD4 count increased from 326 to 536 cells/μL (P < 0.001), the median CD4 lymphocyte percentage rose from 5.8% before treatment to 15.4% (P < 0.001), and the median viral load fell from 5.9 to 2.2 log10 copies/mL after 6 months of HAART (P < 0.001). Among 43 infants, 47% and 67% achieved viral suppression to less than 100 copies/mL and 400 copies/mL, respectively, after 6 months of HAART.
Conclusion
Good early clinical and virologic response to NNRTI-based HAARTwas observed in HIV-1–infected Kenyan children with advanced HIV-1 disease.
doi:10.1097/QAI.0b013e318042d613
PMCID: PMC3380073  PMID: 17356470
antiretroviral; children; HIV-1; response
20.  Predictors of Early Mortality in a Cohort of Human Immunodeficiency Virus Type 1-Infected African Children 
Background
Pediatric human immunodeficiency virus type 1 (HIV-1) infection follows a bimodal clinical course with rapid progression in 10 – 45% of children before the age of 2 years and slower progression in the remainder. A prospective observational study was undertaken to determine predictors of mortality in HIV-1-infected African infants during the first 2 years of life.
Methods
Infants in a perinatal cohort identified to be HIV-1-infected by DNA PCR were followed monthly to 1 year, then quarterly to 2 years or death.
Results
Among 62 HIV-1-infected infants, infection occurred by the age of 1 month in 56 (90%) infants, and 32 (52%) died at median age of 6.2 months. All infant deaths were caused by infectious diseases, most frequently pneumonia (75%) and diarrhea (41%). Univariate predictors of infant mortality included maternal CD4 count <200 cells/μl [hazard ratio (HR), 3.4; P = 0.008], maternal anemia (HR = 3.7; P = 0.005), delivery complications (HR = 2.7; P = 0.01), low birth weight (HR = 4.1; P = 0.001), weight, length and head circumference ≤5th percentile at age 1 month (HR = 3.7, P = 0.003; HR = 5.8, P < 0.001; and HR = 10.4, P < 0.001, respectively), formula-feeding (HR = 4.0; P = 0.01), infant CD4% ≤15% (HR = 5.5; P = 0.01), infant CD4 count <750 (HR = 9.7; P = 0.006) and maternal death (HR = 2.9, P = 0.05). In multivariate analysis, maternal CD4 count <200 (HR = 2.7; P = 0.03) and delivery complications (HR = 3.4; P = 0.005) were independently associated with infant mortality.
Conclusions
Advanced maternal HIV disease, maternal anemia, delivery complications, early growth faltering, formula-feeding and low infant CD4 were predictors of early mortality in African HIV-1-infected infants. In resource-poor settings, these predictors may be useful for early identification and treatment of high risk infants.
PMCID: PMC3380074  PMID: 15194835
Human immunodeficiency virus type 1; disease progression; mortality; predictors
21.  Hormonal contraception and HIV-1 disease progression among postpartum Kenyan women 
AIDS (London, England)  2007;21(6):749-753.
Objective
To assess the immediate and longer-term effects of the use of hormonal contraception on the progression of HIV-1 disease in postpartum women.
Design
A prospective cohort study.
Methods
Information on contraceptive use, breastfeeding and intercurrent illnesses was obtained from HIV-infected postpartum Kenyan women monthly in the first year postpartum and quarterly in the second year. Blood was collected for T-cell subset analyses and HIV-1-RNA levels at months 1, 3, 6, 9, 12, 18, and 24 postpartum. The immediate effect of the initiation of oral contraceptive pills (OCP) and depot medroxyprogesterone acetate (DMPA) was assessed by comparing the change in the HIV-1-RNA plasma viral load and CD4 T-cell counts among women remaining off these contraceptive methods with those initiating them. The longer-term effects of OCP and DMPA on disease progression were assessed using Loess curves and linear mixed effects models to compare changes over the first 24 months postpartum in these same disease progression markers.
Results
There were no significant immediate or longer-term effects of the use of OCP or DMPA on HIV-1-RNA plasma viral loads and CD4 T-cell counts in this cohort of HIV-infected postpartum Kenyan women.
Conclusion
Comprehensive contraceptive counselling for HIV-1-infected women requires an understanding of the effects of various contraceptive methods on HIV-1 disease progression. In this study, hormonal contraception reassuringly had no immediate or longer-term effects on the rate of disease progression in chronically HIV-1-infected postpartum women. This highly effective family planning method may provide a useful and safe option for the prevention of mother-to-child transmission of HIV-1.
doi:10.1097/QAD.0b013e328032790f
PMCID: PMC3380082  PMID: 17413696
Contraception; depot medroxyprogesterone acetate; HIV-1; oral contraceptive pill; postpartum; progression
22.  Human Leukocyte Antigen (HLA) B*18 and Protection against Mother-to-Child HIV Type 1 Transmission 
Human leukocyte antigen (HLA) molecules regulate the cellular immune system and may be determinants of infant susceptibility to human immunodeficiency virus type 1 (HIV-1) infection. Molecular HLA typing for class I alleles was performed on infants followed in a Kenyan perinatal cohort. Early HIV-1 infection status was defined as infection occurring at birth or month 1, while late infection via breast milk was defined as first detection of HIV-1 after 1 month of age. Likelihood ratio tests based on a proportional hazards model adjusting for maternal CD4 T cell count and HIV-1 viral load at 32 weeks of gestation were used to test associations between infant allelic variation and incident HIV-1 infection. Among 433 infants, 76 (18%) were HIV-1 infected during 12 months of follow-up. HLA B*18 was associated with a significantly lower risk of early HIV-1 transmission [relative risk (RR) = 0.26; 95% confidence interval (CI) 0.04–0.82], and none of the 24 breastfeeding infants expressing HLA B*18 who were uninfected at month 1 acquired HIV-1 late via breast milk. We observed a trend toward increased early HIV-1 acquisition for infants presenting HLA A*29 (RR = 2.0; 95% CI 1.0–3.8) and increased late HIV-1 acquisition via breast milk for both Cw*07 and Cw*08 (RR = 4.0; 95% CI 1.0–17.8 and RR = 7.2; 95% CI 1.2–37.3, respectively). HLA B*18 may protect breast-feeding infants against both early and late HIV-1 acquisition, a finding that could have implications for the design and monitoring of HIV-1 vaccines targeting cellular immune responses against HIV-1.
doi:10.1089/0889222041524616
PMCID: PMC3380108  PMID: 15307911
23.  Effects of Valacyclovir on Markers of Disease Progression in Postpartum Women Co-Infected with HIV-1 and Herpes Simplex Virus-2 
PLoS ONE  2012;7(6):e38622.
Objective
Herpes simplex virus type 2 (HSV-2) suppression has been shown to reduce HIV-1 disease progression in non-pregnant women and men, but effects on pregnant and postpartum women have not been described.
Methods
We analyzed data from a cohort of Kenyan women participating in a randomized clinical trial of HSV-2 suppression. Pregnant HIV-1-seropositive, HSV-2-seropositive women who were not eligible for antiretroviral therapy (WHO stage 1–2, CD4>250 cells/µl) were randomized to either 500 mg valacyclovir or placebo twice daily from 34 weeks gestation through 12 months postpartum. Women received zidovudine and single-dose nevirapine for prevention of mother-to-child HIV-1 transmission. HIV-1 progression markers, including CD4 count and plasma HIV-1 RNA levels, were measured serially. Multivariate linear regression was used to compare progression markers between study arms.
Results
Of 148 women randomized, 136 (92%) completed 12 months of postpartum follow-up. While adjusted mean CD4 count at 12 months (565 cells/µl placebo arm, 638 cells/µl valacyclovir arm) increased from antenatal levels in both arms, the mean CD4 count increase was 73 cells/µl higher in the valacyclovir arm than placebo arm (p = 0.03). Mean increase in CD4 count was 154 cells/µl in the valacyclovir arm, almost double the increase of 78 cells/µl in the placebo arm. At 12 months, adjusted HIV-1 RNA levels in the placebo arm increased by 0.66 log10 copies/ml from baseline, and increased by only 0.21 log10 copies/ml in the valacyclovir arm (0.40 log10 copies/ml difference, p = 0.001).
Conclusion
Women randomized to valacyclovir suppressive therapy during pregnancy and postpartum had greater increases in CD4 counts and smaller increases in plasma HIV-1 RNA levels than women in the placebo arm. Valacyclovir suppression during pregnancy and breastfeeding may improve outcomes and delay antiretroviral therapy for HIV-1/HSV-2 co-infected women.
doi:10.1371/journal.pone.0038622
PMCID: PMC3373516  PMID: 22701683
24.  Cofactors for HIV-1 Incidence during Pregnancy and Postpartum Period 
Current HIV Research  2010;8(7):510-514.
Objectives
To estimate HIV-1 incidence and cofactors for HIV-1 incidence during pregnancy and postpartum.
Design
Retrospective study among women who were HIV seronegative during pregnancy.
Methods
Mothers accompanying their infants for routine 6-week immunizations at 6 maternal child health clinics in Nairobi and Western Kenya were tested for HIV-1 after completing a questionnaire that included assessment of sociodemographics, obstetric history and HIV-1 risk perception.
Results
Of 2,135 mothers who had tested HIV-1 seronegative antenatally, 2,035 (95.3%) accepted HIV-1 re-testing at 6 weeks postpartum. Of these, 53 (2.6%) were HIV-1 seropositive yielding an estimated HIV-1 incidence of 6.8 (95% CI: 5.1-8.8) per 100 woman-years). Mothers who seroconverted were more likely to be employed (45.3% vs 29.0%, p=0.01), married (96.2 vs 86.6%, p=0.04) and from a higher HIV-1 prevalence region (60.4% in Western Kenya vs 28.8% in Nairobi, p<0.001). Among married women, those in polygamous relationship were significantly more likely to seroconvert (19.6% vs 6.7%, p<0.001). In multivariate analysis, region and employment independently predicted seroconversion.
Conclusions
Repeat HIV-1 testing in early postpartum was highly acceptable and resulted in detection of substantial HIV-1 incidence during pregnancy and postpartum period. Within prevention of mother-to-child HIV-1 transmission programs strategic approaches to prevent maternal HIV-1 acquisition during pregnancy are urgently needed.
PMCID: PMC3372399  PMID: 20946093
Seroconversion; pregnancy; incidence; sub Saharan Africa; risk factors; heterosexual transmission
25.  Morbidity Among HIV-1–Infected Mothers in Kenya 
Background
Much of the burden of morbidity affecting women of childbearing age in sub-Saharan Africa occurs in the context of HIV-1 infection. Understanding patterns of illness and determinants of disease in HIV-1–infected mothers may guide effective interventions to improve maternal health in this setting.
Methods
We describe the incidence and cofactors of comorbidities affecting peripartum and postpartum HIV-1–infected women in Kenya. Women were evaluated by clinical examination and standardized questionnaires during pregnancy and for up to 2 years after delivery.
Results
Five hundred thirty-five women were enrolled in the cohort (median CD4 count of 433 cells/mm3) and accrued 7736 person-months of follow-up. During 1-year follow-up, the incidence of upper respiratory tract infections was 161 per 100 person-years, incidence of pneumonia was 33 per 100 person-years, incidence of tuberculosis (TB) was 11 per 100 person-years, and incidence of diarrhea was 63 per 100 person-years. Immunosuppression and HIV-1 RNA levels were predictive for pneumonia, oral thrush, and TB but not for diarrhea; CD4 counts <200 cells/mm3 were associated with pneumonia (relative risk [RR] = 2.87, 95% confidence interval [CI]: 1.71 to 4.83), TB (RR = 7.14, 95% CI: 2.93 to 17.40) and thrush. The risk of diarrhea was significantly associated with crowding (RR = 1.86, 95% CI: 1.19 to 2.92) and breast-feeding (RR = 1.71, 95% CI: 1.19 to 2.44). Less than 10% of women reported hospitalization during 2-year follow-up; mortality risk in the cohort was 1.9% and 4.8% for 1 and 2 years, respectively.
Conclusions
Mothers with HIV-1, although generally healthy, have substantial morbidity as a result of common infections, some of which are predicted by immune status or by socioeconomic factors. Enhanced attention to maternal health is increasingly important as HIV-1–infected mothers transition from programs targeting the prevention of mother-to-child transmission to HIV care clinics.
doi:10.1097/QAI.0b013e318141fcc0
PMCID: PMC3372412  PMID: 17667334
HIV/AIDS; HIV-1 progression; maternal health; morbidity; postpartum; pregnancy; prevention of mother-to-child transmission; women

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