Effectiveness of the CoronaVac vaccine in older adults during a gamma variant associated epidemic of covid-19 in Brazil: test negative case-control study.
Otavio T RanzaniMatt D T HitchingsMurilo DorionTatiana Lang D'AgostiniRegiane Cardoso de PaulaOlivia Ferreira Pereira de PaulaEdlaine Faria de Moura VillelaMario Sergio Scaramuzzini TorresSilvano Barbosa de OliveiraWade SchulzMaria AlmironRodrigo SaidRoberto Dias de OliveiraPatricia Vieira da SilvaWildo Navegantes de AraújoJean Carlo GorinchteynJason R AndrewsDerek A T CummingsAlbert I KoJulio Henrique da Rosa CrodaPublished in: BMJ (Clinical research ed.) (2021)
Vaccination with CoronaVac was associated with a reduction in symptomatic covid-19, hospital admissions, and deaths in adults aged ≥70 years in a setting with extensive transmission of the gamma variant. Vaccine protection was, however, low until completion of the two dose regimen, and vaccine effectiveness was observe to decline with increasing age among this elderly population.