Comparative effectiveness and duration of protection of ChAdOx1, CoronaVac, BNT162b2, mRNA-1273, and Ad26.COV2.S COVID-19 vaccines for symptomatic and hospitalized Mu, Delta, and Omicron: A test-negative case-control study.
Paternina-Caicedo A., Quevedo DS., Ríos DS., Moyano D., Alvis-Guzmán N., Alviz-Zakzuk NR., Salcedo F., Moyano L., Ramírez-Suarez J., Smith AD., De la Hoz-Restrepo F.
ObjectiveWe carried out a study to estimate the vaccine effectiveness (VE) of homologous vaccination schedules against COVID-19, using data from mandatory information systems from Bogota, Colombia.MethodsA test-negative case-control study in adults from Bogota (Colombia), between March 1st of 2021 and February 25th of 2022. We assess VE among symptomatic COVID-19 cases during the Mul, Delta, and Omicron predominance periods in Bogota, with controls matched by sex, age (±5 years), and date of testing (±7 days), using a case:control ratio of 1:1. We selected homologous vaccination schedules with ChAdOx1, CoronaVac, BNT162b2, mRNA-1273, and Ad26.COV2.S. VE was reported as one minus the odds ratio in adjusted conditional logistic regressions, with their 95% confidence intervals (CI). A p-value Results52,913 cases were matched to controls, 16,722 for Mu, 14,094 for Delta, and 22,097 for Omicron. VE was high against COVID-19 during Mu weeks with full vaccination using the monovalent BNT162b2 (VE: 69; 95% CI, 65 to 72) vaccine and ChAdOx1 (VE: 64; 95% CI, 31 to 81) and significantly lower with CoronaVac (P ConclusionOur study provides further evidence on the protective effect of mRNA vaccines for Omicron, and warrant that the duration of protection against symptomatic infection may last for only a few months.