COVID-19: impact of original, Gamma, Delta, and Omicron variants of SARS-CoV-2 in vaccinated and unvaccinated pregnant and postpartum women

ABSTRACT Introduction This study compares the clinical characteristics and disease progression of vaccinated and unvaccinated pregnant and postpartum women positive for the original, Gamma, Delta, and Omicron variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using Brazilian epidemiological data. Methods Data of pregnant or postpartum patients with coronavirus disease 2019 (COVID-19) SARS-CoV-2 confirmed using polymerase chain reaction from February 2020 to July 2022 were extracted from a Brazilian national database. The patients were divided based on vaccination status and viral variant (original, Gamma, Delta, and Omicron). The patients’ demographic data, clinical characteristics, comorbidities, signs, symptoms, and outcomes were retrospectively compared. Results Data from 10,003 pregnant and 2,361 postpartum women were extracted from the database. Among unvaccinated patients, postpartum women were more likely to be admitted to the intensive care unit (ICU). These patients were more likely to require invasive ventilation when infected with the original, Gamma, and Omicron variants and were more likely to die when infected with the original and Gamma variants. Patients who were vaccinated had reduced adverse outcomes including ICU admission, requirement for invasive ventilation, and death. Conclusion Postpartum women were more likely to develop severe COVID-19 that required ICU admission or invasive ventilatory support or led to death, among all variants, especially when the patients were unvaccinated. Therefore, the risk of severe COVID-19 should not be underestimated after delivery. Vaccinated patients had a lower risk of severe outcomes. Vaccination should be a top priority in pregnant and postpartum patients. WHAT IS ALREADY KNOWN ON THIS TOPIC The obstetric population has a higher risk of adverse outcomes due to coronavirus disease 2019 (COVID-19). Few studies have compared the outcomes of pregnant and postpartum patients or vaccinated and unvaccinated patients; however, no studies have separately investigated the effects of each viral variant. WHAT THIS STUDY ADDS Postpartum women are more likely to have adverse outcomes, including the requirements for intensive care and invasive ventilation and death, compared with pregnant women. Vaccinated women had fewer adverse outcomes. The viral variants did not significantly affect the outcomes of these patients. HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE, OR POLICY The risks of COVID-19 infection should not be underestimated in postpartum women. Postpartum women infected with COVID-19, especially those who are not vaccinated, should be monitored carefully. Vaccination should be a top priority in pregnant and postpartum women.