# Effectiveness of Vaccination Against COVID-19 in Brazil: Case-Control Study

> **NCT05621928** · — · UNKNOWN · sponsor: **The Immunobiological Technology Institute (Bio-Manguinhos) / Oswaldo Cruz Foundation (Fiocruz)** · enrollment: 3920 (estimated)

## Conditions studied

- COVID-19 Vaccines

## Interventions

_None listed._

## Key facts

- **NCT ID:** NCT05621928
- **Lead sponsor:** The Immunobiological Technology Institute (Bio-Manguinhos) / Oswaldo Cruz Foundation (Fiocruz)
- **Sponsor class:** OTHER
- **Phase:** —
- **Study type:** OBSERVATIONAL
- **Status:** UNKNOWN
- **Start date:** 2022-02-07
- **Primary completion:** 2023-10-31
- **Final completion:** 2024-12-30
- **Target enrollment:** 3920 (ESTIMATED)
- **Last updated:** 2024-02-07


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05621928

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05621928, "Effectiveness of Vaccination Against COVID-19 in Brazil: Case-Control Study". Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/clinical/NCT05621928. Licensed CC0.

---

*[Clinical trials dataset](/datasets/clinical-trials) · CC0 1.0*