The Benefits of COVID-19 Vaccination for Pregnant Patients Hospitalized with Respiratory Symptoms: A Retrospective Cohort Study in South Brazil

Objectives: SARS-CoV-2 infection is a known risk factor for adverse health outcomes in pregnancy, affecting both maternal and neonatal health. Mounting evidence suggests that even a single dose of an approved COVID-19 vaccine protects against severe SARS-CoV-2 infection and is safe for both pregnant persons and neonates. Southern Brazil was heavily affected by the COVID-19 pandemic, and the protective effects of the vaccine on maternal and neonatal health are not well described. This study aims to examine the protective effects of maternal COVID-19 vaccination on both maternal and neonatal outcomes following SARS-CoV-2 infection during pregnancy. Methods: This is a retrospective cohort study that leveraged medical data from a tertiary center in South Brazil to compare maternal and infant outcomes between hospitalized pregnant persons with and without SARS-CoV-2 infection between 1 March 2020, and 1 March 2023. Results: In total, 524 patients were enrolled, including 275 pregnant patients with confirmed SARS-CoV-2 infection and 249 without infection. SARS-CoV-2 infection was associated with maternal ventilator support (adjusted Risk Ratio [aRR] = 1.48, 95% Confidence Interval [95% CI]: 1.08–2.03), while receipt of at least one dose of COVID-19 vaccine was associated with protection against maternal sepsis (aRR = 0.14, 95% CI: 0.03–0.56), intensive care unit (ICU) admission (aRR = 0.27, 95% CI: 0.10–0.68), need for ventilator support (aRR = 0.60, 95% CI: 0.43–0.84), infant admission to the neonatal intensive care unit (NICU) (aRR = 0.62, 95% CI: 0.47–0.82), and neonatal respiratory distress (aRR = 0.60, 95% CI: 0.43–0.83). Conclusions: These findings further underscore the importance of maternal vaccination against COVID-19 during pregnancy. Even one dose of vaccine was protective against a variety of maternal and neonatal outcomes. Prenatal care should encourage COVID-19 vaccination in pregnancy.