HIV prevalence and awareness among adults presenting for enrolment into a study of people at risk for HIV in Kisumu County, Western Kenya.

INTRODUCTION: Despite declines in new HIV diagnoses both globally and in Kenya, parts of Western Kenya still report high HIV prevalence and incidence. We evaluated HIV prevalence to inform the development of policies for strategic and targeted HIV prevention interventions. METHODS: Adult participants aged 18-35 years were recruited in Kisumu County and screened for HIV for a prospective HIV incidence cohort. Questionnaires assessed HIV-associated risk behaviors. Participants who tested positive for HIV were disaggregated into groups based on prior knowledge of their HIV status: previously-diagnosed and newly-diagnosed. In separate analyses by prior knowledge, robust Poisson regression was used to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for factors potentially associated with a positive HIV test in each group, as compared to participants without HIV. RESULTS: Of 1059 participants tested for HIV, 196 (18.5%) had a positive HIV test. Among PLWH, 78 (39.8%) were newly diagnosed with HIV at screening. After adjusting for other variables, previously-diagnosed HIV was more common among females than males (PR 2.70, 95%CI 1.69-4.28), but there was no observed sex difference in newly-diagnosed HIV prevalence (PR 1.05, 95%CI 0.65-1.69). Previously-diagnosed HIV was also more common among people reporting consistent use of condoms with primary sexual partners as compared to inconsistent condom use (PR 3.19, 95%CI 2.09-4.86), but newly-diagnosed HIV was not associated with such a difference between consistent and inconsistent condom use (PR 0.73, 95%CI 0.25-2.10). CONCLUSION: Prevalence of newly-diagnosed HIV was high, at approximately 8% of participants, and not statistically different between genders, highlighting the need for improved HIV case finding regardless of sex. The higher prevalence of previously-diagnosed HIV in female participants may reflect higher rates of HIV testing through more encounters with the healthcare system. Higher prevalence of consistent condom use amongst those previously-diagnosed suggests behavioral change to reduce HIV transmission, a potential benefit of policies to facilitate earlier HIV diagnosis.

Lassa virus in novel hosts: insights into the epidemiology of lassa virus infections in southern Nigeria.

Identification of the diverse animal hosts responsible for spill-over events from animals to humans is crucial for comprehending the transmission patterns of emerging infectious diseases, which pose significant public health risks. To better characterize potential animal hosts of Lassa virus (LASV), we assessed domestic and non-domestic animals from 2021-2022 in four locations in southern Nigeria with reported cases of Lassa fever (LF). Birds, lizards, and domestic mammals (dogs, pigs, cattle and goats) were screened using RT-qPCR, and whole genome sequencing was performed for lineage identification on selected LASV positive samples. Animals were also screened for exposure to LASV by enzyme-linked immunosorbent assay (ELISA). Among these animals, lizards had the highest positivity rate by PCR. Genomic sequencing of samples in most infected animals showed sub-lineage 2 g of LASV. Seropositivity was highest among cattle and lowest in pigs. Though the specific impact these additional hosts may have in the broader virus-host context are still unknown - specifically relating to pathogen diversity, evolution, and transmission - the detection of LASV in non-rodent hosts living in proximity to confirmed human LF cases suggests their involvement during transmission as potential reservoirs. Additional epidemiological data comparing viral genomes from humans and animals, as well as those circulating within the environment will be critical in understanding LASV transmission dynamics and will ultimately guide the development of countermeasures for this zoonotic health threat.

Safety and immunogenicity of a purified inactivated Zika virus vaccine candidate in adults primed with a Japanese encephalitis virus or yellow fever virus vaccine in the USA: a phase 1, randomised, double-blind, placebo-controlled clinical trial.

BACKGROUND: Zika virus infection is a threat to at-risk populations, causing major birth defects and serious neurological complications. Development of a safe and efficacious Zika virus vaccine is, therefore, a global health priority. Assessment of heterologous flavivirus vaccination is important given co-circulation of Japanese encephalitis virus and yellow fever virus with Zika virus. We investigated the effect of priming flavivirus naive participants with a licensed flavivirus vaccine on the safety and immunogenicity of a purified inactivated Zika vaccine (ZPIV). METHODS: This phase 1, placebo-controlled, double-blind trial was done at the Walter Reed Army Institute of Research Clinical Trials Center in Silver Spring, MD, USA. Eligible participants were healthy adults aged 18-49 years, with no detectable evidence of previous flavivirus exposure (by infection or vaccination), as measured by a microneutralisation assay. Individuals with serological evidence of HIV, hepatitis B, or hepatitis C infection were excluded, as were pregnant or breastfeeding women. Participants were recruited sequentially into one of three groups (1:1:1) to receive no primer, two doses of intramuscular Japanese encephalitis virus vaccine (IXIARO), or a single dose of subcutaneous yellow fever virus vaccine (YF-VAX). Within each group, participants were randomly assigned (4:1) to receive intramuscular ZPIV or placebo. Priming vaccinations were given 72-96 days before ZPIV. ZPIV was administered either two or three times, at days 0, 28, and 196-234. The primary outcome was occurrence of solicited systemic and local adverse events along with serious adverse events and adverse events of special interest. These data were analysed in all participants receiving at least one dose of ZPIV or placebo. Secondary outcomes included measurement of neutralizing antibody responses following ZPIV vaccination in all volunteers with available post-vaccination data. This trial is registered at ClinicalTrials.gov, NCT02963909. FINDINGS: Between Nov 7, 2016, and Oct 30, 2018, 134 participants were assessed for eligibility. 21 did not meet inclusion criteria, 29 met exclusion criteria, and ten declined to participate. 75 participants were recruited and randomly assigned. 35 (47%) of 75 participants were male and 40 (53%) were female. 25 (33%) of 75 participants identified as Black or African American and 42 (56%) identified as White. These proportions and other baseline characteristics were similar between groups. There were no statistically significant differences in age, gender, race, or BMI between those who did and did not opt into the third dose. All participants received the planned priming IXIARO and YF-VAX vaccinations, but one participant who received YF-VAX dropped out before receipt of the first dose of ZPIV. 50 participants received a third dose of ZPIV or placebo, including 14 flavivirus-naive people, 17 people primed with Japanese encephalitis virus vaccine, and 19 participants primed with yellow fever vaccine. Vaccinations were well tolerated across groups. Pain at the injection site was the only adverse event reported more frequently in participants who received ZPIV than in those who received placebo (39 [65%] of 60 participants, 95% CI 51·6-76·9 who received ZPIV vs three [21·4%] of 14 who received placebo; 4·7-50·8; p=0·006). No patients had an adverse event of special interest or serious adverse event related to study treatment. At day 57, the flavivirus-naive volunteers had an 88% (63·6-98·5, 15 of 17) seroconversion rate (neutralising antibody titre ≥1:10) and geometric mean neutralising antibody titre (GMT) against Zika virus of 100·8 (39·7-255·7). In the Japanese encephalitis vaccine-primed group, the day 57 seroconversion rate was 31·6% (95% CI 12·6-56·6, six of 19) and GMT was 11·8 (6·1-22·8). Participants primed with YF-VAX had a seroconversion rate of 25% (95% CI 8·7-49·1, five of 20) and GMT of 6·6 (5·2-8·4). Humoral immune responses rose substantially following a third dose of ZPIV, with seroconversion rates of 100% (69·2-100; ten of ten), 92·9% (66·1-99·8; 13 of 14), and 60% (32·2-83·7, nine of 15) and GMTs of 511·5 (177·6-1473·6), 174·2 (51·6-587·6), and 79 (19·0-326·8) in the flavivirus naive, Japanese encephalitis vaccine-primed, and yellow fever vaccine-primed groups, respectively. INTERPRETATION: We found ZPIV to be well tolerated in flavivirus naive and primed adults but that immunogenicity varied significantly according to antecedent flavivirus vaccination status. Immune bias towards the flavivirus antigen of initial exposure and the timing of vaccination may have impacted responses. A third ZPIV dose overcame much, but not all, of the discrepancy in immunogenicity. The results of this phase 1 clinical trial have implications for further evaluation of ZPIV's immunisation schedule and use of concomitant vaccinations. FUNDING: Department of Defense, Defense Health Agency; National Institute of Allergy and Infectious Diseases; and Division of Microbiology and Infectious Disease.

Developing standards of care for HIV prevention research in developing countries -- a case study of 10 research centers in Eastern and Southern Africa.

Standards of care provided to volunteers in HIV prevention research in developing countries are evolving. Inconsistency in standards, particularly within a research network highlights the need to balance volunteers' health and wellness with the efficient conduct of research. Ten research centers (RC's) in East and Southern Africa affiliated with the International AIDS Vaccine Initiative (IAVI) were studied using a mixed methods approach to understand variations, similarities and gaps in services provided, recipients of services, referral systems, and barriers to referral uptake. These data were then used to develop expected standards across the 10 RCs. Findings indicated that RCs consistently provided HIV risk reduction and family planning (FP) counseling, male condoms, management of sexually transmitted infections, CD-4 counts, and general medical care to volunteers and non-research volunteers. Services that were less consistently provided on-site included: female condoms, adult male circumcision (AMC), antiretroviral therapy (ART) and post-exposure prophylaxis (PEP) in case of rape. The FP options provided on-site varied, with few providing implants, intrauterine devices, tubal ligation, and vasectomy. Most RCs had established referral systems for ART, AMC, PEP, and FP, but few had referral points for psychosocial services. Few RCs had comprehensive guidelines on referrals other than those related to adverse events. Findings indicate that the greatest challenges for referral uptake were transportation and health care costs, poor quality and inconsistency of services at some referral points. Few RCs covered the cost of referrals for non-study related adverse events. A collaborative process between IAVI and the RCs was undertaken to reach consensus on expected standards of care. A set of required and recommended services to be provided on-site or by referral was developed. In developing such standards, we tried to balance scientific priorities, equity, contextual realities, community expectations, and cost-effectiveness.

Extended antiretroviral prophylaxis to reduce breast-milk HIV-1 transmission.

BACKGROUND: Effective strategies are urgently needed to reduce mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) through breast-feeding in resource-limited settings. METHODS: Women with HIV-1 infection who were breast-feeding infants were enrolled in a randomized, phase 3 trial in Blantyre, Malawi. At birth, the infants were randomly assigned to one of three regimens: single-dose nevirapine plus 1 week of zidovudine (control regimen) or the control regimen plus daily extended prophylaxis either with nevirapine (extended nevirapine) or with nevirapine plus zidovudine (extended dual prophylaxis) until the age of 14 weeks. Using Kaplan-Meier analyses, we assessed the risk of HIV-1 infection among infants who were HIV-1-negative on DNA polymerase-chain-reaction assay at birth. RESULTS: Among 3016 infants in the study, the control group had consistently higher rates of HIV-1 infection from the age of 6 weeks through 18 months. At 9 months, the estimated rate of HIV-1 infection (the primary end point) was 10.6% in the control group, as compared with 5.2% in the extended-nevirapine group (P<0.001) and 6.4% in the extended-dual-prophylaxis group (P=0.002). There were no significant differences between the two extended-prophylaxis groups. The frequency of breast-feeding did not differ significantly among the study groups. Infants receiving extended dual prophylaxis had a significant increase in the number of adverse events (primarily neutropenia) that were deemed to be possibly related to a study drug. CONCLUSIONS: Extended prophylaxis with nevirapine or with nevirapine and zidovudine for the first 14 weeks of life significantly reduced postnatal HIV-1 infection in 9-month-old infants. (ClinicalTrials.gov number, NCT00115648.)

High risk of neutropenia in HIV-infected children following treatment with artesunate plus amodiaquine for uncomplicated malaria in Uganda.

BACKGROUND: Artemisinin-based combination therapies are rapidly being adopted for the treatment of malaria in Africa; however, there are limited data on their safety and efficacy among human immunodeficiency virus (HIV)-infected populations. METHODS: We compared malaria treatment outcomes between cohorts of HIV-infected and HIV-uninfected children in Uganda who were observed for 18 and 29 months, respectively. Malaria was treated with artesunate plus amodiaquine, and outcomes were assessed using standardized guidelines. HIV-infected children received trimethoprim-sulfamethoxazole prophylaxis and antiretroviral therapy in accordance with current guidelines. RESULTS: Twenty-six HIV-infected participants experiencing 35 episodes of malaria and 134 HIV-uninfected children experiencing 258 episodes of malaria were included in the study. Twelve HIV-infected children were receiving antiretroviral therapy, 11 of whom were receiving zidovudine. Malaria treatment was highly efficacious in both the HIV-infected and HIV-uninfected cohorts (28-day risk of recrudescence, 0% and 3.6%, respectively); however, there was a trend towards increased risk of recurrent malaria among the HIV-uninfected children (2.9% vs. 13.2%; p = .08). Importantly, the risk of neutropenia 14 days after initiation of treatment with artesunate plus amodiaquine was higher among HIV-infected children than among HIV-uninfected children (45% vs. 6%; p < .001). The severity of all episodes of neutropenia in HIV-uninfected children was mild to moderate, and 16% of episodes of neutropenia in the HIV-infected cohort were severe or life-threatening (neutrophil count, <750 cells/mm(3)). In the HIV-infected cohort, the risk of neutropenia was significantly higher among children who received antiretroviral therapy than among those who did not receive antiretroviral therapy (75% vs. 26%; p < .001). CONCLUSIONS: Artesunate plus amodiaquine was highly efficacious for malaria treatment in HIV-infected children but was associated with a high risk of neutropenia, especially in the context of concurrent antiretroviral use. Our findings highlight an urgent need for evaluation of alternative antimalarial therapies for HIV-infected individuals.

Effects of trimethoprim-sulfamethoxazole and insecticide-treated bednets on malaria among HIV-infected Ugandan children.

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis and insecticide-treated bednets reduce malaria risk among HIV-infected adults. The efficacy of TMP/SMX may be diminished where antifolate resistance to malaria is high. We evaluated the efficacy of these interventions for malaria prevention among Ugandan children. METHODS: We concurrently followed 300 HIV-infected children aged 1-10 years and a community-based cohort of 561 healthy children aged 1-11 years over 11 months in Kampala, Uganda. The HIV-infected children received TMP/SMX prophylaxis and insecticide treated bednets. In the community cohort, insecticide-treated bednets were introduced during the observation period. Children from both cohorts were followed using a standardized protocol to measure the incidence of malaria. RESULTS: Only nine episodes of malaria were diagnosed among HIV-infected children (incidence = 0.07/person-year) in comparison with 440 episodes among children from the community (incidence = 0.90/person-year; P < 0.0001). The use of insecticide-treated bednets was associated with a 43% reduction in malaria incidence (P < 0.001), and a combination of TMP/SMX and use of insecticide-treated bednets with a 97% reduction in malaria incidence (P < 0.001). The prevalence of five mutations associated with antifolate resistance was high among malaria cases detected in both the HIV (100%) and community cohorts (75%). Malaria accounted for only 4% of febrile episodes in the HIV cohort in comparison with 33% in the community-based cohort (P < 0.0001). CONCLUSION: In a malaria endemic area with a high level of molecular markers of antifolate resistance, the combined use of TMP/SMX prophylaxis and insecticide-treated bednets was associated with a dramatic reduction in malaria incidence among HIV-infected children.

Low-dose daily iron supplementation for 12 months does not increase the prevalence of malarial infection or density of parasites in young Zanzibari children.

Conflicting evidence exists on the possible role of iron supplementation in the predisposition to malaria infection or the enhancement of its clinical severity. Where anemia prevalence is >40%, current guidelines are to provide low-dose daily iron to young children for up to 18 mo. Earlier studies used doses higher than the current guidelines, intermittent doses, or have supplemented for durations < or = 4 mo. We aimed to assess the effect of low-dose, long-term iron supplementation on malaria infection using a double-blind, placebo-controlled, randomized design, and to examine possible subgroup effects by season and child age. The study was conducted in Pemba Island, Zanzibar, where Plasmodium falciparum malaria has year-round high transmission. A community-based sample of 614 children 4-71 mo old was randomly allocated to 10 mg/d iron or placebo for 12 mo. Outcome measures were the prevalence and density of malaria infection, which was assessed by blood films at monthly intervals. At baseline, 94.4% were anemic (hemoglobin < 110 g/L), 48.1% were stunted (height-for-age Z-score less than -2) and >80% had malaria-positive blood films. No significant differences in malariometric indices were observed between children in the iron-supplemented and placebo groups. Parasite density was higher in certain months and in younger children, but iron supplementation was not associated with any malarial infection outcome in any season or age subgroup. We conclude that in this environment of high malaria transmission, daily oral low-dose supplementation of iron for 12 mo did not affect the prevalence of malaria infection or parasite density.