Safety and Incidence of COVID-19 Following ChAdOx1(AZD1222) COVID-19 Vaccination in Botswana.

Nisar et al. 1 assessed the effectiveness of various COVID-19 vaccines in Pakistan using a testnegative case-control design.They report moderate effectiveness of various vaccines and higher effectiveness mRNA vaccines compared with inactivated vaccines.Although they assessed the impact of concurrent medical conditions, they were only a few cases of immunosuppression contributing to < 3% of the study population and approximately 87% of the participants received Sinopharm and Sinovac, and 1% received the Oxford/AstraZeneca vaccine.AstraZeneca (AZD1222), formerly called ChAdOx1, previously demonstrated robust immunogenicity after a single dose with favorable safety profiles. 2,3Despite Botswana's high HIV prevalence, treatment has been hugely successful with over 90% of all adults living with HIV currently receiving antiretroviral therapy (ART). 4There are no data on the safety and effectiveness of AZD1222 in this high HIV prevalence setting.We conducted a single-arm, open-label interventional multi-site study (D8111C00013/ESR-21-21311) to monitor vaccine safety and the occurrence of symptomatic COVID-19 infections, hospitalizations and deaths among individuals vaccinated with AZD1222 between September 15, 2021, and May 18, 2022, at five sites in Botswana.The study was approved by the Health and Research Development Committee (HRDC#00936).All participants provided written informed consent.We screened 9419 and enrolled 9140 participants (Fig. 1).Of the participants included in this study, 9124 (99.8%) were receiving at least one dose of AZD1222 and remaining in the study 22 days after the first dose without having a SARS-CoV-2 RT-PCR positive confirmed COVID-19 infection, Vaccinated Set (VS); 2275 of these par-