Introduction: Brazil has been facing the pandemic of COVID-19 since march 2020. More than 540,000 people have died from this disease in the country. Some estimates indicate that the population exposed to SARS-CoV-2 represents 1 to 20%. However, these data are questionable due to the number of asymptomatic and untested individuals. As a result, vaccination for COVID- 19 has become the main means of achieving herd immunity. Objectives: To demonstrate, through local sampling, that broad and rapid vaccination may decrease the rate of COVID-19 detection in individuals potentially exposed to the SARS-CoV-2 virus. Methods: A total of 1,128 individuals were studied, including students and health professionals from Centro Universitário FMABC, who received the two doses of the vaccine for COVID-19 (Oxford/Astrazeneca ® and CoronaVac®). Results: In the studied period, there was a 41% reduction in the demand for RT-PCR tests after vaccination. And a 78.3% reduction in positive results after vaccination started. Conclusion: The results of this study showed that even vaccinating a population with higher exposure to the risk of contamination significantly reduced test positivity and the demand to perform these tests. This emphasizes that vaccination is the best strategy to achieve herd immunity and reduce the spread of the disease.
