Effects on Newborns of COVID Vaccine During Pregnancy Shown in Large Study

Is it safe to receive a COVID-19 mRNA vaccination during pregnancy? That question has been on the minds of every expectant parent since the vaccines became widely available.

Now, in one of the largest studies of its kind, scientists in Ontario have endeavored to answer this question.

"Many women are understandably nervous about receiving vaccines during pregnancy," the study's lead author, Sarah Jorgensen, a researcher at the University of Toronto, told Newsweek. "Our study hopefully provides them with some reassurance about the safety of the COVID-19 vaccines during pregnancy for newborns and young infants."

Their study, published in the journal JAMA Pediatrics, studied 142,000 live births across Ontario, and 60 percent of the infants had been exposed to one or more COVID-19 vaccine doses while the mother was pregnant.

"We assessed the safety of maternal COVID-19 vaccination during pregnancy for newborns and infants and did not find an increase in adverse outcomes," Jorgensen said. "Some of these outcomes were actually improved in infants of mothers vaccinated during pregnancy."

The study concluded that vaccination during pregnancy was associated with lower risks of severe disease during the first 28 days after birth and neonatal intensive care unit admissions. There was also no association between maternal vaccination during pregnancy and hospital readmission during the first 28 days after birth or after six months.

"These improved outcomes might be because the vaccines protect mothers from severe COVID-19 during pregnancy, which, in turn, is associated with pregnancy complications and harms to the fetus/newborn," Jorgensen said. "Or it could be because women who get the vaccine are generally from higher-income areas and have other health-related behaviors associated with improved newborn and infant outcomes. Most likely both explanations are somewhat responsible."

In a previous study, the team also found that COVID-19 vaccination during pregnancy protected infants from COVID-19 infection during the first few months of their lives.

"Our research has specifically focused on newborn and infant health effects when mothers get vaccinated during pregnancy, but other researchers have found the vaccines protect mothers from COVID-19 with no increase in pregnancy complications," Jorgensen said.

Compared with previous research, this latest study was able to draw from an extensive and diverse pool of health data from across the Canadian province.

"Ontario has universal health insurance and rich health administrative data on the 15 million residents of the province," Jorgensen said. "The availability of these data allowed us to complete one of the largest studies to date that assesses the safety of COVID-19 vaccination during pregnancy for newborns and infants."

She continued: "Our study included a larger proportion of women vaccinated during pregnancy, including all trimesters, than most previous studies assessing infant outcomes. We also assessed a wide range of important infant health effects. And we had data on infants up to 6 months of age, which is the longest follow-up to date."