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

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

Status
Completed
Phases
Unknown
Study type
Observational
Source
ClinicalTrials.gov
Registry ID
NCT04355338
Acronym
AVISA
Enrollment
3520
Registered
2020-04-21
Start date
2020-10-25
Completion date
2024-10-30
Last updated
2025-02-06

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19

Keywords

COVID-19, SARS-CoV-2 infection, Asymptomatic Infections, Antibodies, Neutralizing, Immunity, Humoral

Brief summary

This is an observational study, meaning that no interventions is tested, to determine incidence of SARS-CoV-2 infection and COVID-19 in different clinical sites in Brazil in several age groups. The study aims to assess baseline number of infected participants and perform a follow-up along two years to determine the new cases occurring among participants during the period. All participants will collect blood samples to get more details on the immune response.

Detailed description

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.

Interventions

None listed

Sponsors

Butantan Institute
Lead SponsorOTHER_GOV

Study design

Observational model
COHORT
Time perspective
PROSPECTIVE

Eligibility

Sex/Gender
ALL
Healthy volunteers
Yes

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

Design outcomes

Primary

MeasureTime frameDescription
Incidence of SARS-CoV-2 infection24 monthsNumber of cases with serological/virological diagnosis for SARS-Co-2 infection
Incidence of COVID-1924 monthsNumber of cases of symptomatic SARS-CoV-2 infection

Secondary

MeasureTime frameDescription
Incidence of hospitalization due to COVID-1924 yearsNumber of cases of hospitalization due to symptomatic SARS-Co-2 infection
Level of neutralizing antibodies24 monthsLevel of neutralizing antibodies in participants with SARS-Co-2 infection
Previous SARS-CoV-2 infection6 monthsPositive serology for SARS-Co-2 infection at baseline

Other

MeasureTime frameDescription
Incidence of deaths due to COVID-1924 monthsNumber of deaths due to COVID-19
Incidence of COVID-19 cases requiring mechanical ventilation24 monthsNumber of COVID-19 cases requiring mechanical ventilation
Incidence of sequels after COVID-1924 monthsNumber and description of sequels attributed to COVID-19
Incidence of SARS-CoV-2 reinfection24 monthsNumber of a new SARS-CoV-2 infection in an individual with a proven previous infection

Countries

Brazil

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026