The Importance of COVID Vaccine for Pregnant Women

The fall season brings a new COVID-19 vaccine and CDC officials are encouraging everyone over 6 months old to get it. However, there has been lingering concerns among the public as to whether pregnant women should get the vaccine and how it might affect their unborn child.

The Yale School of Public Health’s Emerging Infections Program recently participated in a CDC study that highlights the importance of COVID vaccination to protect pregnant women and their newborns. The CT EIP is part of the CDC’s national COVID-NET Surveillance team, which represents about 10% of the country. The program contributed Connecticut data to the study collected by Yale CT EIP Program Manager Kimberly Yousey-Hindes, MPH.

Yale School of Public Health Professor Dr. Linda Niccolai, PhD, studies vaccine-preventable diseases and serves as director of the CT EIP. Niccolai recently took a moment to discuss the CDC’s findings and the importance of COVID-19 vaccination coverage among pregnant women and women who breastfeed to protect their newborns and decrease hospitalization rates.

Linda Niccolai (LN): This study examined 1,148 infants hospitalized with COVID-19 from October 2022 to April 2024. Infants less than 6 months of age have among the highest rates of hospitalization with COVID-19 compared to other age groups. Infants with COVID-19 frequently have severe illness with approximately 1 in 5 admitted to the intensive care unit and almost 1 in 20 requiring mechanical ventilation. Infants 6 months of age and younger are not eligible to be vaccinated for COVID-19, but they may be protected by maternal vaccination during pregnancy. The percentage of infants hospitalized with COVID-19 whose mothers had been vaccinated during pregnancy decreased from 18% during October 2022–September 2023 to less than 5% during October 2023–April 2024. Nine infants died in the hospital; all were born to mothers with no record of vaccination during pregnancy.

LN: The CT EIP at YSPH is one of twelve states that conduct population-based surveillance for COVID-19 hospitalizations. These data contributed to the current study. Our team collected data on infant hospitalizations from electronic medical records and ascertained the vaccination status of each infant’s biological mother. The CT EIP is a CDC-funded partnership with the Connecticut Department of Public Health.

LN: Maternal vaccination during pregnancy has been shown to be safe and effective in protecting young infants from COVID-19 hospitalization, and COVID-19 vaccination is recommended by CDC for all persons 6 months of age and older, including those who are pregnant. Pregnant persons that receive a COVID-19 vaccine can pass protective antibodies to their baby through transplacental transfer. In the setting of low maternal COVID-19 vaccination and high rates of severe disease in young infants, public health prevention efforts should focus on ensuring that pregnant persons receive COVID-19 vaccination to protect themselves and their vulnerable infants. Health care providers should be prepared to discuss the safety and effectiveness of COVID-19 vaccines with their pregnant patients, and the risks to themselves and their infants associated with not being vaccinated.