Mass vaccination can be an important tool to rapidly contain pathogens. In 2021, two doses of the recombinant COVID-19 vaccine ChadOx1-nCoV19 were offered to all 18–60-year-olds in Botucatu, Brazil, through a mass vaccination campaign. P95 contributed to a study that used this unique opportunity to assess the effectiveness and safety of the vaccine in real-world settings. The first and second vaccine doses were administered to 77,683 and 74,051 citizens, respectively. The effectiveness against COVID-19 disease of any severity was 74.5% after dose 1 and 81.3% after dose 2, which is comparable to the efficacy observed in clinical trials. Moreover, vaccination was well tolerated and did not raise safety concerns. Together, these results show the beneficial effect of this mass vaccination campaign in Botucatu. 

Effectiveness and safety data were described in two publications:  

https://www.ncbi.nlm.nih.gov/pubmed/36311567 

https://www.sciencedirect.com/science/article/pii/S0264410X22010106?via%3Dihub