Effectiveness of a nation-wide COVID-19 vaccination program in Mexico

BACKGROUND Vaccination has been effective in ameliorating the impact of COVID-19. However, estimation of vaccine effectiveness (VE) is still unavailable for some widely used vaccines and underrepresented groups. Here, we report on the effectiveness of a nation-wide COVID-19 vaccination program in Mexico. METHODS We used a test-negative design within a national COVID-19 surveillance system to assess VE of the BNT162b2, mRNA-12732, Gam-COVID-Vac, Ad5-nCoV, Ad26.COV2.S, ChAdOx1 and CoronaVac vaccines, against SARS-CoV-2 infection, COVID-19 related hospitalization and death for adults ≥18 years in Mexico. VE was estimated using Cox proportional hazard models considering time-varying vaccination status in partial and fully vaccinated individuals compared to unvaccinated adults, adjusted by age, sex, comorbidities and municipality. We also estimated VE for adults ≥60 years, for cases with diabetes and comparing periods with predominance of variants B.1.1.519 and B.1.617.2. RESULTS We assessed 793,487 vaccinated compared to 4,792,338 unvaccinated adults between December 24th, 2020, and September 27th, 2021. VE against SARS-CoV-2 infection was highest for fully vaccinated individuals with mRNA-12732 (91.5%, 95%CI 90.3-92.4) and Ad26.COV2.S (82.2%, 95%CI 81.4-82.9), whereas for COVID-19 related hospitalization were BNT162b2 (84.3%, 95%CI 83.6-84.9) and Gam-COVID-Vac (81.4% 95%CI 79.5-83.1) and for mortality BNT162b2 (89.8%, 95%CI 89.2-90.2) and mRNA-12732 (93.5%, 95%CI 86.0-97.0). VE for all evaluated vaccines was reduced for adults ≥60 years, people with diabetes, and in periods of Delta variant predominance. CONCLUSIONS All evaluated vaccines were effective against SARS-CoV-2 infection and COVID-19 related hospitalization and death. Mass vaccination campaigns with multiple vaccine products are feasible and effective to maximize vaccination coverage. ### Competing Interest Statement SECL, GCS, CAZJ, GGR, RCA and HLG work at the Mexican Ministry of Health and oversee monitoring SARS-Cov-2 epidemiological surveillance and designing COVID-19 vaccination policies in Mexico. Data analysis and interpretation was primarily conducted by members of the team independent of these duties. ### Funding Statement This research was supported by Instituto Nacional de Geriatria. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All proceedings and evaluations for the use of restricted anonymized data were approved by the Research and Ethics committee at Instituto Nacional de Geriatria, with approval number DI-PI-006/2020 I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Code and materials are available for reproducibility of results at https://github.com/oyaxbell/covid_vaccines/. Data is available upon request to the General Directorate of Epidemiology of the Mexican Ministry of Health.