The Number and Complexity of Pure and Recombinant HIV-1 Strains Observed within Incident Infections during the HIV and Malaria Cohort Study Conducted in Kericho, Kenya, from 2003 to 2006

Characterization of HIV-1 subtype diversity in regions where vaccine trials are conducted is critical for vaccine development and testing. This study describes the molecular epidemiology of HIV-1 within a tea-plantation community cohort in Kericho, Kenya. Sixty-three incident infections were ascertained in the HIV and Malaria Cohort Study conducted in Kericho from 2003 to 2006. HIV-1 strains from 58 of those individuals were full genome characterized and compared to two previous Kenyan studies describing 41 prevalent infections from a blood bank survey (1999–2000) and 21 infections from a higher-risk cohort containing a mix of incident and prevalent infections (2006). Among the 58 strains from the community cohort, 43.1% were pure subtypes (36.2% A1, 5.2% C, and 1.7% G) and 56.9% were inter-subtype recombinants (29.3% A1D, 8.6% A1CD, 6.9% A1A2D, 5.2% A1C, 3.4% A1A2CD, and 3.4% A2D). This diversity and the resulting genetic distance between the observed strains will need to be addressed when vaccine immunogens are chosen. In consideration of current vaccine development efforts, the strains from these three studies were compared to five candidate vaccines (each of which are viral vectored, carrying inserts corresponding to parts of gag, pol, and envelope), which have been developed for possible use in sub-Saharan Africa. The sequence comparison between the observed strains and the candidate vaccines indicates that in the presence of diverse recombinants, a bivalent vaccine is more likely to provide T-cell epitope coverage than monovalent vaccines even when the inserts of the bivalent vaccine are not subtype-matched to the local epidemic.

CHALLENGES IN MANAGEMENT OF WARFARIN ANTI-COAGULATION IN ADVANCED HIV/AIDS PATIENTS WITH VENOUS THROMBOTIC EVENTS--A CASE SERIES FROM A RESEARCH CLINIC IN RURAL KERICHO, KENYA

BACKGROUND

Venous thrombotic events (VTE) occur at high ratesin HIV/AIDS patients and are likely under-diagnosed in rural sub-Saharan Africa.

OBJECTIVE

To describe clinical presentations and challenges in the management of VTE in patients with advanced HIV/AIDS.

DESIGN

Case series from patients enrolled in a prospective observational cohort study.

SETTINGS

A clinical research centre in rural Kericho, Kenya.

SUBJECTS

Two hundred patients with median age 38 (30-47) years, BMI 16.9 (12.4-20.3) kg/m2, haemoglobin 9.3 (6.8-13.4) g/dL, CD4+ T-cell count 27 (4-77) cells/mm and plasma HIV RNA 5.23 (3.70-5.88) log10 copies/mL.

INTERVENTIONS

VTE cases were diagnosed by clinical presentation and Doppler/ radiographic confirmation. Anti-coagulation therapy was managed by a multidisciplinary team; patients were initiated on enoxaparin or heparin followed by warfarin.

RESULTS

Over two years,11patients (5.5%) experienced VTE. All but one (10/11,90.9%) case occurred within six months of starting ART. Nine patients had peripheral VTE (five popliteal, four femoral) and two had cerebral sinus thromboses. VTE was diagnosed 52 (1-469) days after ART initiation, and 81.8% of cases were outpatients at presentation. All patients received at least one concomitant medication that could significantly interact with warfarin (efavirenz, nevirapine, lopinavir/ritonavir, rifampicin, trimethoprim-sulfamethoxazole, and fluconazole). A median of 39 (10-180) days and eight (4-22) additional clinic visits were required to achieve/maintain a therapeutic INR of 2-3. Two minor bleeding complications occurred. No recurrent VTE cases were observed.

CONCLUSION

Consideration of VTE and preparedness for management in patients with advanced HIV/AIDS starting ART is critical in sub-Saharan Africa. Overcoming challenges in anti-coagulation is possible in rural settings using a multidisciplinary team approach.

Reference ranges for the clinical laboratory derived from a rural population in Kericho, Kenya

The conduct of Phase I/II HIV vaccine trials internationally necessitates the development of region-specific clinical reference ranges for trial enrollment and participant monitoring. A population based cohort of adults in Kericho, Kenya, a potential vaccine trial site, allowed development of clinical laboratory reference ranges. Lymphocyte immunophenotyping was performed on 1293 HIV seronegative study participants. Hematology and clinical chemistry were performed on up to 1541 cohort enrollees. The ratio of males to females was 1.9:1. Means, medians and 95% reference ranges were calculated and compared with those from other nations. The median CD4+ T cell count for the group was 810 cells/microl. There were significant gender differences for both red and white blood cell parameters. Kenyan subjects had lower median hemoglobin concentrations (9.5 g/dL; range 6.7-11.1) and neutrophil counts (1850 cells/microl; range 914-4715) compared to North Americans. Kenyan clinical chemistry reference ranges were comparable to those from the USA, with the exception of the upper limits for bilirubin and blood urea nitrogen, which were 2.3-fold higher and 1.5-fold lower, respectively. This study is the first to assess clinical reference ranges for a highland community in Kenya and highlights the need to define clinical laboratory ranges from the national community not only for clinical research but also care and treatment.

Reference ranges for the clinical laboratory derived from a rural population in Kericho, Kenya

The conduct of Phase I/II HIV vaccine trials internationally necessitates the development of region-specific clinical reference ranges for trial enrolment and participant monitoring. A population based cohort of adults in Kericho, Kenya, a potential vaccine trial site, allowed development of clinical laboratory reference ranges. Lymphocyte immunophenotyping was performed on 1293 HIV seronegative study participants. Hematology and clinical chemistry were performed on up to 1541 cohort enrollees. The ratio of males to females was 1.9∶1. Means, medians and 95% reference ranges were calculated and compared with those from other nations. The median CD4+ T cell count for the group was 810 cells/µl. There were significant gender differences for both red and white blood cell parameters. Kenyan subjects had lower median hemoglobin concentrations (9.5 g/dL; range 6.7–11.1) and neutrophil counts (1850 cells/µl; range 914–4715) compared to North Americans. Kenyan clinical chemistry reference ranges were comparable to those from the USA, with the exception of the upper limits for bilirubin and blood urea nitrogen, which were 2.3-fold higher and 1.5-fold lower, respectively. This study is the first to assess clinical reference ranges for a highland community in Kenya and highlights the need to define clinical laboratory ranges from the national community not only for clinical research but also care and treatment.

The Protective Effect of Circumcision on HIV Incidence in Rural Low-Risk Men Circumcised Predominantly by Traditional Circumcisers in Kenya

BACKGROUND

Three randomized controlled trials (RCTs) have demonstrated that male circumcision prevents female-to-male HIV transmission in sub-Saharan Africa. Data from prospective cohort studies are helpful in considering generalizability of RCT results to populations with unique epidemiologic/cultural characteristics.

METHODS

Prospective observational cohort sub-analysis. A total of 1378 men were evaluated after 2 years of follow-up. Baseline sociodemographic and behavioral/HIV risk characteristics were compared between 270 uncircumcised and 1108 circumcised men. HIV incidence rates (per 100 person-years) were calculated, and Cox proportional hazards regression analyses estimated hazard rate ratios (HRs).

RESULTS

Of the men included in this study, 80.4% were circumcised; 73.9% were circumcised by traditional circumcisers. Circumcision was associated with tribal affiliation, high school education, fewer marriages, and smaller age difference between spouses (P < 0.05). After 2 years of follow-up, there were 30 HIV incident cases (17 in circumcised and 13 in uncircumcised men). Two-year HIV incidence rates were 0.79 (95% confidence interval [CI]: 0.46 to 1.25) for circumcised men and 2.48 (95% CI: 1.33 to 4.21) for uncircumcised men corresponding to a HR = 0.31 (95% CI: 0.15 to 0.64). In one model controlling for sociodemographic factors, the HR increased and became non-significant (HR = 0.55; 95% CI: 0.20 to 1.49).

CONCLUSIONS

Circumcision by traditional circumcisers offers protection from HIV infection in adult men in rural Kenya. Data from well-designed prospective cohort studies in populations with unique cultural characteristics can supplement RCT data in recommending public health policy.