Assessment of Incidence of SARS-CoV-2 Infection and COVID-19 in Brazil (AVISA)

This is an observational longitudinal study to assess incidence of SARS-CoV-2 infection in Brazil. The study sample is stratified in nine age groups according decades of life, equally distributed in both sexes, with an expected incidence of 10%, at least, during the study period of 24 months. For the first age groups, (0-9, 10-19 and 20-29 years), sample was calculated with the minimum expected incidence of COVID-19 among infected, regardless severity, is 10%. For the latest age groups (30-39, 40-49, 50-59, 60-69, 70-79 and 80+), the sample was calculated with the expected minimum incidence of hospitalization due to COVID-19 according to estimates per age group reported by Verity R et al. https://doi.org/10.1016/S1473-3099(20)30243-7 After the consent procedure, all participants will have a short interview, a IgG/IgM SARS-CoV-2 rapid test and a blood withdrawal to obtain serum for neutralizing antibodies. These procedures will be repeated every four weeks until the end of the study. Individuals with symptoms compatible will be followed-up to confirm COVID-19 diagnosis as well as to assess severity, need for hospitalization and assisted ventilation, sequels, and eventual reinfection. Levels of neutralizing antibodies and other immune markers will be prospectively assessed in all infected participants, either asymptomatic and symptomatic.

Primary outcomes

• Incidence of SARS-CoV-2 infection [24 months]: Number of cases with serological/virological diagnosis for SARS-Co-2 infection
• Incidence of COVID-19 [24 months]: Number of cases of symptomatic SARS-CoV-2 infection

Secondary outcomes

• Incidence of hospitalization due to COVID-19 [24 years]: Number of cases of hospitalization due to symptomatic SARS-Co-2 infection
• Level of neutralizing antibodies [24 months]: Level of neutralizing antibodies in participants with SARS-Co-2 infection
• Previous SARS-CoV-2 infection [6 months]: Positive serology for SARS-Co-2 infection at baseline

Other outcomes

• Incidence of SARS-CoV-2 reinfection [24 months]: Number of a new SARS-CoV-2 infection in an individual with a proven previous infection
• Incidence of COVID-19 cases requiring mechanical ventilation [24 months]: Number of COVID-19 cases requiring mechanical ventilation
• Incidence of deaths due to COVID-19 [24 months]: Number of deaths due to COVID-19
• Incidence of sequels after COVID-19 [24 months]: Number and description of sequels attributed to COVID-19

Sex: All, accepts healthy volunteers

Inclusion Criteria:

* Any sex or age
* Providing informed consent
* Agreement with all study visits, procedure and contacts

Exclusion Criteria:

* Previous suspected or confirmed COVID-19
* Febrile illness in the latest 72 hours
* Olfactory or gustatory dysfunction in the last three months
* Healthcare worker in a service with routine attention to COVID-19 patients
* Any conditions that can might hurdle participant's compliance to the study in tha opinion of the study team

• Fernanda Boulos, MD, PhD, Study director, Butantan Institute