Seroepidemiological assessment of SARS-CoV-2 vaccine responsiveness and associated factors in the vaccinated community of the Casablanca-Settat Region, Morocco.

Assessing the prevalence of SARS-CoV-2 IgG positivity through population-based serological surveys is crucial for monitoring COVID-19 vaccination efforts. In this study, we evaluated SARS-CoV-2 IgG positivity within a provincial cohort to understand the magnitude of the humoral response against the SARS-CoV-2 vaccine and to inform evidence-based public health decisions. A community-based cross-sectional seroprevalence study was conducted, involving 10,669 participants who received various vaccines (two doses for BBIBP-CorV/Sinopharm, Covishield vaccine, and Pfizer/BioNTech, and one dose for Johnson & Johnson's Janssen COVID-19 vaccine). The study spanned 16 provinces in the Casablanca-Settat region from February to June 2022, during which comprehensive demographic and comorbidity data were collected. We screened samples for the presence of IgG antibodies using the SARS-CoV-2 IgG II Quant assay, which quantifies antibodies against the receptor-binding domain (RBD) of the spike (S) protein, measured on the Abbott Architect i2000SR. The overall crude seroprevalence was 96% (95% CI: 95.6-96.3%), and after adjustment for assay performance, it was estimated as 96.2% (95% CI: 95.7-96.6). The adjusted overall seroprevalences according to vaccine brands showed no significant difference (96% for BBIBP-CorV/Sinopharm, 97% for ChAdOx1 nCoV-19/Oxford/AstraZeneca, 98.5% for BNT162b2/Pfizer-BioNTech, and 98% for Janssen) (p = 0.099). Participants of older age, female sex, those with a history of previous COVID-19 infection, and those with certain chronic diseases were more likely to be seropositive among ChAdOx1 nCoV-19/Oxford/AstraZeneca and BBIBP-CorV/Sinopharm vaccinee groups. Median RBD antibody concentrations were 2355 AU/mL, 3714 AU/mL, 5838 AU/mL, and 2495 AU/mL, respectively, after two doses of BBIBP-CorV/Sinopharm, ChAdOx1 nCoV-19/Oxford/AstraZeneca, BNT162b2/Pfizer-BioNTech, and after one dose of Janssen (p < 0.0001). Furthermore, we observed that participants vaccinated with ChAdOx1 nCoV-19/Oxford/AstraZeneca and BBIBP-CorV/Sinopharm with comorbid chronic diseases exhibited a more pronounced response to vaccination compared to those without comorbidities. In contrast, no significant differences were observed among Pfizer-vaccinated participants (p > 0.05). In conclusion, our serosurvey findings indicate that all four investigated vaccines provide a robust humoral immune response in the majority of participants (more than 96% of participants had antibodies against SARS-CoV-2). The BNT162b2 vaccine was found to be effective in eliciting a strong humoral response compared to the other three vaccines. However, challenges still remain in examining the dynamics and durability of immunoprotection in the Moroccan context.

Genomic-informed pathogen surveillance in Africa: opportunities and challenges.

The ongoing COVID-19 pandemic has highlighted the need to incorporate pathogen genomics for enhanced disease surveillance and outbreak management in Africa. The genomics of SARS-CoV-2 has been instrumental to the timely development of diagnostics and vaccines and in elucidating transmission dynamics. Global disease control programmes, including those for tuberculosis, malaria, HIV, foodborne pathogens, and antimicrobial resistance, also recommend genomics-based surveillance as an integral strategy towards control and elimination of these diseases. Despite the potential benefits, capacity remains low for many public health programmes in Africa. The COVID-19 pandemic presents an opportunity to reassess and strengthen surveillance systems and potentially integrate emerging technologies for preparedness of future epidemics and control of endemic diseases. We discuss opportunities and challenges for integrating pathogen genomics into public health surveillance systems in Africa. Improving accessibility through the creation of functional continent-wide networks, building multipathogen sequencing cores, training a critical mass of local experts, development of standards and policies to facilitate best practices for data sharing, and establishing a community of practice of genomics experts are all needed to use genomics for improved disease surveillance in Africa. Coordination and leadership are also crucial, which the Africa Centres for Disease Control and Prevention seeks to provide through its institute for pathogen genomics.

Secondhand Smoke Exposure Among Nonsmoking Adolescents in West Africa.

OBJECTIVES: We estimated the prevalence and determinants of secondhand smoke (SHS) exposure among nonsmoking adolescents in 9 West African countries. METHODS: We conducted a pooled analysis with nationally representative 2006 to 2009 Global Youth Tobacco Survey data. We used descriptive statistics to determine the prevalence of SHS exposure and inferential statistics using a multivariable logistic regression model to determine factors associated with SHS exposure. We investigated average marginal effect results that show the probability of SHS exposure, adjusting for all other attributes. RESULTS: SHS exposure inside the home ranged from 13.0% to 45.0%; SHS exposure outside the home ranged from 24.7% to 80.1%. Parental or peer smoking behaviors were significantly associated with higher probability of SHS exposure in all 9 countries. Knowledge of smoking harm, support for smoking bans, exposure to antismoking media messages, and receptivity of school tobacco education were significantly associated with higher SHS exposure in most countries. CONCLUSIONS: West African policymakers should adopt policies consistent with Article 8 of the World Health Organization Framework Convention on Tobacco Control and its guidelines and public health education to promote smoke-free households.