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Background: Chlamydia trachomatis is a leading cause of poor reproductive health outcomes in women and may also increase HIV risk. Infections are often asymptomatic and undiagnosed in developing countries, where syndromic management is standard-of-care. Studies from South Africa estimate a prevalence of up to 40% in adolescent girls, which has undoubtedly increased due to disruption of health services during the pandemic. Chlamydia remains a major health concern, with vaccines urgently required. Although there is some evidence for partial protection after natural infection, this is poorly defined, highlighting the need to understand chlamydia immunity in the context of its natural history. Thus, we characterised chlamydia-specific CD4+ T cell responses in highly exposed young women, to understand the impact of multiple exposures. Methods: T cell responses were measured by multiparameter flow cytometry in HIV-uninfected young women (16-22 years old) with either confirmed chlamydia infection (NAAT+) or positive IgG ELISA (n=45). PBMCs were stimulated with a single peptide pool covering C. trachomatis major outer membrane protein and intracellular IFN-γ, IL-2 and TNF-α measured in CD3+CD4+ T cells. Nonparametric statistical tests were used for all data analysis. Results: Of the 45 women included in the study, 24/45 (53%) were experiencing a primary chlamydia infection (NAAT+/IgG-); 16/45 (36%) had a persistent/recurrent infection (NAAT+/IgG+); and 5/45 (11%) were NAAT-/IgG+, considered evidence of previous/recovered infection. All recovered women had detectable chlamydia-specific CD4+ T cells producing any cytokine, compared to ~80% of women with active infection (NAAT+/IgG+ or NAAT+/IgG-). Notably, CD4+ IFN-γ+ T cells were found in all five recovered women, but in only 50% and 33% of women with persistent and primary infections, respectively. Consequently, recovered women had a significantly higher frequency of chlamydia-specific CD4+T cells producing IFN-γ than those with primary infections (p=0.007). We also found a weak positive correlation between chlamydia-specific CD4+ IFN-γ responses and the relative concentrations of chlamydia-specific IgG (r=0.31, p=0.036). Conclusion: We report an important potential association between chlamydia-specific Th1/IFN-γ responses and relative exposure in young women, which may reflect immune cell migration dynamics during active infection. These findings may have significant implications for mucosal vaccine strategies and evaluation and should be explored further. [ABSTRACT FROM AUTHOR]

Background: In low-middle income countries (LMICs), such as South Africa, there is an urgent need to strengthen reproductive health care (RHC) services, and improve testing for sexually transmitted infections (STIs). Self-testing, self-sampling and e- Health platforms are potential affordable, accessible tools to achieve this and require further exploration. We have recently reviewed programmatic, ethical and economic considerations for implementations of self-testing/self-sampling point-of-care tests for STIs, including HIV, in the context of LMICs. Despite demonstrable efficacy, many available tests are not currently available in LMICs, including South Africa, and the regulatory framework to oversee these need to be developed. Here, we aimed to evaluate online self-testing and self-sampling service providers available in South Africa, as a mapping exercise to support development of national regulatory guidelines. Methods: South African e-Health providers of STI tests (including both self-sampling and self-testing) were identified by searching Google (Nov 2022 to Jan 2023). Information on tests and associated services were collected from various websites, with further information obtained from providers via an online survey. This information was compared with South African Health Products Regulatory Authority (SAHPRA) and Health Professions Council of South Africa (HPCSA) standards for existing diagnostics and STI management. Results: Thirty-four individual tests were identified, of which 30 were self-tests and four were selfsampling tests, available from nine unique service providers (Table 1). These included tests for HIV (8/34), syphilis (6/34), herpes simplex virus (HSV) (5/34), Chlamydia trachomatis (4/34), Neisseria gonorrhoeae (4/34), Hepatitis B (2/34), Hepatitis C (3/34) and 2 multiplexed tests that included Trichomonas vaginalis, C. trachomatis and N. gonorrhoeae. Most were either antigen-based (12/34) or antibody-based rapid tests (13/34), and required blood (14/34). Only 5/34 required urogenital sampling, while 11/34 did not state the sample type required. Of the 34 tests, 56% were manufactured in South Africa, with the mean cost per service being 20 United States Dollars (range: 1- 62 USD). Conclusion: e-Health and self-testing for STIs are available in South Africa and offer an important approach to improving care. This exercise will aid national policymakers in drafting guidelines for management and regulation of STI self-tests and e- Health providers in South Africa. [ABSTRACT FROM AUTHOR]