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Abstract 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 0.05). 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.

Abstract A continent-wide Africa Task Force for Coronavirus with its six technical working groups was formed to prepare adequately and respond to the novel Coronavirus disease (COVID-19) outbreak in Africa. This research in practice article aimed to describe how the infection prevention and control (IPC) technical working group (TWG) supported Africa Centre for Disease Control and Prevention (Africa CDC) in preparedness and response to COVID-19 on the continent. To effectively address the multifaceted IPC TWG mandate of organizing training and implementing rigorous IPC measures at healthcare service delivery points, the working group was sub-divided into four sub-groups—Guidelines, Training, Research, and Logistics. The action framework was used to describe the experiences of each subgroup. The guidelines subgroup developed 14 guidance documents and two advisories; all of which were published in English. In addition, five of these documents were translated and published in Arabic, while three others were translated and published in French and Portuguese. Challenges faced in the guidelines subgroup included the primary development of the Africa CDC website in English, and the need to revise previously issued guidelines. The training subgroup engaged the Infection Control Africa Network as technical experts to carry out in-person training of IPC focal persons and port health personnel across the African continent. Challenges faced included the difficulty in conducting face-to-face IPC training and onsite technical support due to the lockdown. The research subgroup developed an interactive COVID-19 Research Tracker on the Africa CDC website and conducted a context-based operation and implementation research. The lack of understanding of Africa CDC’s capacity to lead her own research was the major challenge faced by the research subgroup. The logistics subgroup assisted African Union (AU) member states to identify their IPC supply needs through capacity building for IPC quantification. A notable challenge faced by the logistics subgroup was the initial lack of experts on IPC logistics and quantifications, which was later addressed by the recruitment of professionals. In conclusion, IPC cannot be built overnight nor can it be promoted abruptly during outbreaks of diseases. Thus, the Africa CDC should build strong national IPC programmes and support such programmes with trained and competent professionals.