Reactogenicity, Safety, and Immunogenicity of Covid-19 Vaccine Booster

Reactogenicidad, Seguridad e Inmunogenicidad de Dosis de Refuerzo de Vacunas Contra SARS-CoV-2 en Chile (Estudio REFUERZO)

Preliminary data suggest that inactivated vaccine-induced neutralizing antibodies against SARS-CoV-2 decrease at six months after vaccination. Observational, unpublished data also indicate that vaccine effectiveness against Covid-19 wanes over time. Thus, the investigators aimed to determine the reactogenicity, safety, and immunogenicity of a homologous or heterologous booster of SARS-CoV-2 vaccines among people already immunized with an inactivated SARS-CoV-2 vaccine. The study focuses on the elderly population and healthcare workers.

Inclusion Criteria:

• Full immunization with CoronaVac (2 doses; 0,28) prior to April 15, 2021
• Being a resident of any of the eligible Nursing Homes (located in the Metropolitan Region of Chile)
• Healthcare workers of one of the eligible Nursing Homes.
• Healthcare workers of Hospital de Urgencia Asistencia Publica (HUAP, Santiago, Chile)

Exclusion Criteria:

• Prior history of Covid-19
• Not able to consent