The high hospitalization rate of patients with coronavirus disease (COVID-19) has led to the collapse of healthcare systems in many countries. Vaccines for COVID-19 emerged in late 2020, and they have been shown to be a powerful tool to decrease hospitalization numbers in countries that were able to quickly vaccinate a majority of their populations (). The goal of this study was to estimate how many COVID-19-related hospitalizations were prevented in the state of São Paulo (Brazil) because of vaccines […]

Serological surveys, such as EPICOVID19 (), are important to monitor the evolution of COVID-19 in a population. In this letter, we discuss how to best estimate its prevalence. It is well known that the naive estimator of prevalence that consists of counting how many individuals tested positive ignores the possibility of test errors and may therefore substantially bias the conclusions. The often-used Rogan-Gladen estimator () is an alternative that provides corrected confidence intervals based on sensitivity/specificity values. However, this estimator […]