Background: Schistosomiasis is a neglected disease prevalent in tropical and sub-tropical areas of the world, especially in Africa. Detecting the presence of the disease is based on the detection of the parasites in the stool or urine of children and adults. In such studies, typically, data collected on schistosomiasis infection includes information on many negative individuals leading to a high zero inflation. Thus, in practice, counts data with excessive zeros are common. However, the purpose of this analysis is to apply statistical models to the count data and evaluate their performance and results. Methods: This is a secondary analysis of previously collected data. As part of a modelling process, a comparison of the Poisson regression, negative binomial regression and their associated zero inflated and hurdle models were used to determine which offered the best fit to the count data. Results: Overall, 94.1% of the study participants did not have any schistosomiasis eggs out of 1345 people tested, resulting in a high zero inflation. The performance of the negative binomial regression models (hurdle negative binomial (HNB), zero inflated negative binomial (ZINB) and the standard negative binomial) were better than the Poisson-based regression models (Poisson, zero inflated Poisson, hurdle Poisson). The best models were the ZINB and HNB and their performances were indistinguishable according to information-based criteria test values. Conclusion: The zero-inflated negative binomial and hurdle negative binomial models were found to be the most satisfactory fit for modelling the over-dispersed zero inflated count data and are recommended for use in future statistical modelling analyses.

A significant proportion of SARS-CoV-2 infections in Africa were identified as asymptomatic. With the surge of the Omicron variant, asymptomatic participants in epidemiological surveys were key to accurately estimating seroprevalence and true infections in the population. This study assessed seroprevalence, active infections, and circulating variants in Accra, Ghana, during the Omicron wave. Secondary objectives included assessing the association between seroprevalence and sociodemographic factors, vaccination, and adherence to recommended SARS-CoV-2 prevention and control measures. We conducted a cross-sectional survey in Greater Accra in December 2021 using a standardized questionnaire. Serum and naso-oropharyngeal swab samples were collected from 1027 individuals aged ≥ 5 years for the estimation of total antibodies and detection of infection. The study found an overall seroprevalence of 86.8% [95% CI: 84.53–88.77]. PCR test positivity of SARS-CoV-2 was 10%, with the Omicron and Delta variants accounting for 44.1% and 8.8% of infections, respectively. Vaccination (cOR = 10.5, 95% CI: 4.97–26.9, p < 0.001) and older age, particularly the 60+ age group (cOR = 6.05, 95% CI: 2.44–20.2, p < 0.001), were associated with an increase in odds of seropositivity among participants. High seropositivity of SARS-CoV-2 in Accra was an indication of high exposure and transmission rates and/or high vaccine-induced seroprevalence.

Africa reported lower COVID-19-related morbidity and mortality compared to other continents, despite widespread SARS-CoV-2 transmission and limited vaccine access. Proposed immunological explanations include potential pre-existing immunity such as cross-reactive humoral or cellular responses from earlier coronavirus exposures. However, functional immune responses to SARS-CoV-2 in African populations remain poorly characterized. To address this gap, we assessed post-pandemic neutralizing antibody responses against the SARS-CoV-2 D614G variant. We analyzed plasma samples from 989 participants in a cross-sectional survey in Ghana’s Eastern and Greater Accra regions. A live virus neutralization assay using Vero E6 TMPRSS2 cells was employed to quantify SARS-CoV-2 D614G-specific neutralizing antibodies. Responses were assessed across collected demographic data. Urban participants exhibited higher median neutralizing antibody titers than rural counterparts, in both vaccinated and unvaccinated groups (p < 0.0001). Among unvaccinated individuals, median neutralizing antibody titers were comparable across age groups in urban settings. Vaccinated individuals showed elevated median titers across all age groups, with urban residents demonstrating stronger responses. Significant sex-based differences in neutralizing titres were also identified. Our findings reveal marked disparities in functional antibody responses between urban and rural populations, likely shaped by differences in SARS-CoV-2 exposure and vaccination. Continued surveillance and immunological profiling remain key for informing vaccine strategies and future pandemic preparedness.

Background Accurate diagnostic tools are essential for onchocerciasis elimination programs. The SD-Bioline Ov-16 rapid diagnostic test (RDT) has been widely adopted for field surveillance, but its performance compared to molecular methods requires evaluation. This study assesses the concordance between SD-Bioline Ov-16 RDT and quantitative polymerase chain reaction (qPCR) assay for diagnosing onchocerciasis in some endemic communities in Ghana. Methods A community-based cross-sectional study was conducted between September and November 2023 in seven communities across three districts in the Volta and Oti Regions of Ghana. Participants aged ≥ 5 years were recruited using convenience sampling. Dried blood spots were tested using the SD-Bioline Ov-16 RDT, and skin snips were analysed by qPCR targeting the O-150 repeat sequence both from same individuals. Concordance was assessed using kappa statistics, and diagnostic performance was estimated with qPCR as the reference standard. Results Out of 1,705 participants recruited, 902 with complete paired samples were analysed. The overall prevalence was 27.5% (248/902) by Ov-16 RDT and 2.9% (26/902) by qPCR. The highest prevalence was observed in Nkwanta North District (44.6% by RDT, 5.5% by qPCR). Overall concordance between tests was 73.4% with a kappa score of 0.0759 (p < 0.001), indicating poor agreement. The Ov-16 RDT showed 65.4% sensitivity (95% CI: 44.3–82.8%) and 73.6% specificity (95% CI: 70.5–76.6%) when compared to qPCR. Conclusion Poor concordance between Ov-16 RDT and qPCR reflects the fundamental difference between antibody detection (exposure) and parasite detection (active infection). While RDT remains useful for surveillance, its limitations in detecting active low-level infections necessitate improved diagnostic tools to support WHO's 2030 elimination goals. The persistent transmission in Nkwanta North District requires intensified intervention strategies.

Accurate diagnostic tools are essential for onchocerciasis elimination programs. The SD-Bioline Ov-16 rapid diagnostic test (RDT) has been widely adopted f