Efficacy and effectiveness of COVID-19 vaccines in Africa: A systematic review.

BACKGROUND: Data on COVID-19 vaccine effectiveness to support regional vaccine policy and practice are limited in Africa. Thus, this review aimed to evaluate the efficacy and effectiveness of COVID-19 vaccines administered in Africa. METHODS: We systematically searched peer-reviewed randomized controlled trials (RCTs), prospective and retrospective cohort studies, and case-control studies that reported on VE in Africa. We carried out a risk of bias assessment, and the findings of this review were synthesized and presented in a narrative form, including tables and figures. The synthesis was focused on COVID-19 VE against various levels of the disease condition and outcomes (infection, hospitalization or critical, and death), time points, and variants of concern. RESULTS: A total of 13 studies, with a total sample size of 913,285 participants, were included in this review. The majority (8/13) of studies were from South Africa and 38.5% (5/13) were randomized clinical trials. The studies reported that a full dose of Pfizer-BioNTech vaccine had a VE of 100% against COVID-19 infection by Beta (B.1.351) and Delta variants and 96.7% against hospitalization by Delta variant. The Johnson and Johnson vaccine had VE ranging from 38.1%-62.0% against hospitalization and 51.9%- 86% against critical disease by Beta (B 1.351) variant. The Oxford-AstraZeneca vaccine had a VE of 89.4% against hospitalization by the Omicron variant but was not effective against the B.1.351 variant (10.4%). The Sinopharm vaccine had a VE of 67% against infection and 46% against hospitalization by Delta variant. CONCLUSIONS: COVID-19 vaccines administered in Africa were effective in preventing infections, hospitalization, and death. These review findings underscore the need for concerted efforts of all stakeholders to enhance the access and availability of COVID-19 vaccines and reinforce public awareness to reach the high-risk, unvaccinated group of the African population.

Healthcare workers' willingness to receive COVID-19 booster dose and associated factors in the Democratic Republic of the Congo.

The COVID-19 booster dose is considered an important adjunct for the control of the COVID-19 pandemic due to reports of reduced immunity in fully vaccinated individuals. The aims of this study were to assess healthcare workers' intention to receive the booster dose of COVID-19 vaccine and to identify predictive factors among healthcare workers. A cross-sectional study was conducted among healthcare workers selected in two provinces, Kasai Oriental, and Haut-Lomami. Data were collected using a questionnaire administered through structured face-to-face interviews, with respondents using a pre-tested questionnaire set up on the Open Data Kit (ODK Collect). All data were analyzed using SPSS v26.0 (IBM Corporation, Armonk, NY, USA). Vaccination coverage for COVID-19, considering declarations by health workers, is around 85.9% for the province of Kasai Oriental and 85.8% for Haut-Lomami. A total of 975 responses were collected, 71.4% of health workers at Kasai Oriental and 66.4% from Haut-Lomami declared a definite willingness to receive a COVID-19 vaccine booster. The duration of protection was the main reason for accepting a booster COVID-19 dose for 64.6% of the respondents. Logistic regression analysis showed that having chronic diseases (aOR = 2.95 [1.65-5.28]), having already received one of the COVID-19 vaccines (aOR = 2.72 [1.43-5. 19]); the belief that only high-risk individuals, such as healthcare professionals and elderly people suffering from other illnesses, needed a booster dose (aOR = 1.75 [1.10-2.81]). Considering the burden of COVID-19, a high acceptance rate for booster doses could be essential to control the pandemic. Our results are novel and could help policymakers design and implement specific COVID-19 vaccination programs to reduce reluctance to seek booster vaccination.