Change in covid-19 risk over time following vaccination with CoronaVac: test negative case-control study.
Matt D T HitchingsOtavio T RanzaniMargaret L LindMurilo 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 GorinchteynNatalie E DeanJason R AndrewsDerek A T CummingsAlbert I KoJulio Henrique da Rosa CrodaPublished in: BMJ (Clinical research ed.) (2022)
Significant increases in the risk of moderate and severe covid-19 outcomes occurred three months after primary vaccination with CoronaVac among people aged 65 and older. These findings provide supportive evidence for the implementation of vaccine boosters in these populations who received this inactivated vaccine. Studies of waning should include analyses designed to uncover common biases.