Cholera vaccine clinical trials: A cross-sectional analysis of clinical trials registries.

Cholera has been one of the world's biggest public health challenges for centuries. The presence of this disease brings into focus the social determinants of health in different parts of the world. Research and development efforts to find safe and effective Cholera vaccines are critical to decreasing the disease burden from Vibrio cholerae. We searched the International Clinical Trials Registry Platform (ICTRP) and Cochrane Central Register of Controlled Trials (CENTRAL) on 5 March 2023. We included all registered randomized trials studying Cholera vaccines. We used Microsoft Excel to perform a descriptive analysis of the source registry, geographic distribution, recruitment status, phase of trials, and type of trial sponsor and presented the findings using tables and graphs. The search of ICTRP yielded 84 trials, and 315 trials were identified from CENTRAL. Seventy-four trials were included in the analysis. Most of the trials (66%, n = 49) were registered in ClinicalTrials.gov, followed by Clinical Trials Registry - India (9%, n = 7) and the Cuban Public Registry of Clinical Trials (8%, n = 6). The geographical distribution of the trials indicates that 48% (n = 36) of the trials were conducted in Asia, followed by 23% (n = 17) in North America, 15% (n = 11) in Africa, and 11% (n = 8) in Europe. Results further indicate that 81% (n = 60) of trials have a recruitment status "Not recruiting," followed by 12% (n = 9) with a status "recruiting." With the recent surge in Cholera cases and the limited supply of Cholera vaccines, research indicates the need for Cholera vaccine trials to ensure the availability of vaccines, especially in populations affected.

Implementation of couples' voluntary HIV counseling and testing services in Durban, South Africa.

BACKGROUND: Couples' voluntary HIV counseling and testing (CVCT) is an evidence-based intervention that significantly reduces HIV incidence in couples. Despite the high prevalence of HIV and HIV couple serodiscordance in South Africa, there are few CVCT services. METHODS: From February-June 2013, The Rwanda Zambia HIV Research Group provided support, training, and technical assistance for local counselors and promoters to pilot CVCT services in five hospital-based clinics in Durban, South Africa. Client-level data (age, gender, years cohabiting, pregnancy status, previous testing, antiretroviral treatment (ART) status, neighborhood, and test site) collected as a component of routine CVCT service operation is presented stratified by couple serostatus. RESULTS: Twenty counselors and 28 promoters completed training. Of 907 couples (1,814 individuals) that underwent CVCT, prevalence of HIV was 41.8% and prevalence of HIV serodiscordance was 29.5% (19.3% M-F+, 10.3% M + F-). Most participants were 25-34 years of age, and this group had the highest prevalence. Previous individual HIV testing was low (50% for men, 63% for women). Only 4% of couples reported previous CVCT. Most (75%) HIV+ partners were not on ART, and HIV+ individuals in discordant couples were more likely to be on ART than those in concordant positive couples. Pregnancy among HIV+ women was not associated with previous HIV testing or ART use. CONCLUSIONS: Implementation of standard CVCT services was found to be feasible in Durban. The burden of HIV and couple serodiscordance in Durban was extremely high. CVCT would greatly benefit couples in Durban as an HIV prevention strategy.

Knowledge of HIV serodiscordance, transmission, and prevention among couples in Durban, South Africa.

OBJECTIVE: Couples' voluntary HIV counseling and testing (CVCT) significantly decreases HIV transmission within couples, the largest risk group in sub-Saharan Africa, but it is not currently offered in most HIV testing facilities. To roll out such an intervention, understanding locale-specific knowledge barriers is critical. In this study, we measured knowledge of HIV serodiscordance, transmission, and prevention before and after receipt of CVCT services in Durban. DESIGN: Pre- and post-CVCT knowledge surveys were administered to a selection of individuals seeking CVCT services. METHODS: Changes in knowledge scores were assessed with McNemar Chi-square tests for balanced data and generalized estimating equation methods for unbalanced data. RESULTS: The survey included 317 heterosexual black couples (634 individuals) who were primarily Zulu (87%), unemployed (47%), and had at least a secondary level education (78%). 28% of couples proved to be discordant. Only 30% of individuals thought serodiscordance between couples was possible pre-CVCT compared to 95% post-CVCT. One-third thought there was at least one benefit of CVCT pre-CVCT, increasing to 96% post-CVCT. Overall, there were positive changes in knowledge about HIV transmission and prevention. However, many respondents thought all HIV positive mothers give birth to babies with AIDS (64% pre-CVCT, 59% post-CVCT) and that male circumcision does not protect negative men against HIV (70% pre-CVCT, 67% post-CVCT). CONCLUSIONS: CVCT was well received and was followed by improvements in understanding of discordance, the benefits of joint testing, and HIV transmission. Country-level health messaging would benefit from targeting gaps in knowledge about serodiscordance, vertical transmission, and male circumcision.

High frequency of transmitted HIV-1 Gag HLA class I-driven immune escape variants but minimal immune selection over the first year of clade C infection.

In chronic HIV infection, CD8+ T cell responses to Gag are associated with lower viral loads, but longitudinal studies of HLA-restricted CD8+ T cell-driven selection pressure in Gag from the time of acute infection are limited. In this study we examined Gag sequence evolution over the first year of infection in 22 patients identified prior to seroconversion. A total of 310 and 337 full-length Gag sequences from the earliest available samples (median = 14 days after infection [Fiebig stage I/II]) and at one-year post infection respectively were generated. Six of 22 (27%) individuals were infected with multiple variants. There was a trend towards early intra-patient viral sequence diversity correlating with viral load set point (p = 0.07, r = 0.39). At 14 days post infection, 59.7% of Gag CTL epitopes contained non-consensus polymorphisms and over half of these (35.3%) comprised of previously described CTL escape variants. Consensus and variant CTL epitope proportions were equally distributed irrespective of the selecting host HLA allele and most epitopes remained unchanged over 12 months post infection. These data suggest that intrapatient diversity during acute infection is an indicator of disease outcome. In this setting, there is a high rate of transmitted CTL escape variants and limited immune selection in Gag during the first year of infection. These data have relevance for vaccine strategies designed to elicit effective CD8+ T cell immune responses.

Broad and persistent Gag-specific CD8+ T-cell responses are associated with viral control but rarely drive viral escape during primary HIV-1 infection.

OBJECTIVE: We characterized protein-specific CD8 T-cell immunodominance patterns during the first year of HIV-1 infection, and their impact on viral evolution and immune control. METHODS: We analyzed CD8 T-cell responses to the full HIV-1 proteome during the first year of infection in 18 antiretroviral-naïve individuals with acute HIV-1 subtype C infection, all identified prior to seroconversion. Ex-vivo and cultured interferon-γ ELISPOT assays were performed and viruses from plasma were sequenced within defined CTL Gag epitopes. RESULTS: Nef-specific CD8 T-cell responses were dominant during the first 4 weeks after infection and made up 40% of the total responses at this time; yet, by 1 year, responses against this region had declined and Gag responses made up to 47% of all T-cell responses measured. An inverse correlation between the breadth of Gag-specific responses and viral load set point was evident at 26 weeks after infection (P = 0.0081, r = -0.60) and beyond. An inverse correlation between the number of persistent responses targeting Gag and viral set point was also identified (P = 0.01, r = -0.58). Gag-specific responses detectable by the cultured ELISPOT assay correlated negatively with viral load set point (P = 0.0013, r = -0.91). Sequence evolution in targeted and nontargeted Gag epitopes in this cohort was infrequent. CONCLUSIONS: These data underscore the importance of HIV-specific CD8 T-cell responses, particularly to the Gag protein, in the maintenance of low viral load levels during primary infection, and show that these responses are initially poorly elicited by natural infection. These data have implications for vaccine design strategies.

Association of IL-10-promoter genetic variants with the rate of CD4 T-cell loss, IL-10 plasma levels, and breadth of cytotoxic T-cell lymphocyte response during chronic HIV-1 infection.

BACKGROUND: Interleukin-10 (IL-10) is a potent immunoregulatory cytokine. IL-10-promoter polymorphisms have been shown to affect human immunodeficiency virus type 1 (HIV-1) clinical outcomes but the underlying mechanisms are poorly understood. METHODS: We investigated the relationship between IL-10-promoter variants, plasma cytokine levels, immune responses and markers of disease outcome in antiretroviral-naïve HIV-1 chronically infected individuals from South Africa. Two IL-10-promoter single nucleotide polymorphisms (SNPs) were genotyped in 451 participants. Baseline plasma levels of select cytokines were measured for 112 individuals. Viral load, CD4(+) T-cell counts and HIV-1-specific interferon-gamma CD8(+) T-cell immune responses were measured at baseline. CD4(+) T-cell counts were measured longitudinally and rates of CD4(+) T-cell decline computed for 300 study subjects. RESULTS: The minor IL-10-1082G and -592A variants occurred at frequencies of 0.31 and 0.34, respectively. The -592AA genotype associated significantly with attenuated loss of CD4(+) T cells (P = .0496). Individuals possessing -1082GG had significantly higher IL-10 levels compared to -1082AA/AG (P = .0006). The -592AA genotype was associated with greater breadth of virus-specific CD8(+) T-cell responses compared to CC and CA (P = .002 and .004 respectively). CONCLUSIONS: IL-10-promoter variants may influence the rate of HIV-1 disease progression by regulating IL-10 levels and the breadth of CD8(+) T-cell immune responses.