About 4% of pregnant women who received mRNA vaccine had a major health event within a week of their first dose, and about 7% did so after the second dose, according to data collected from more than 191,000 Canadian women. In comparison, 3% of unvaccinated pregnant women reported similar major health events, defined as an illness that caused the person to miss work or school, required medical advice, or prevented them from participating in regular daily activities. The most common major health events after the second dose in pregnant women were a general feeling of being unwell, headache or migraine, and respiratory tract infection. Among a control group of vaccinated but not pregnant people, about 6 percent reported a health event after the first dose and 11 percent after the second, according to the report published online Aug. 11 in The Lancet Infectious Diseases. The study, led by Manish Sadarangani, of the Vaccine Evaluation Center at BC Children’s Hospital Research Institute in Vancouver, is one of the first to compare vaccine side effects between vaccinated pregnant women, unvaccinated pregnant women and a third group that was vaccinated. but not pregnant. Serious health events—defined as requiring an emergency department visit or hospitalization—were rare in all groups (less than 1%). Miscarriage or stillbirth was the most commonly reported adverse pregnancy outcome, but there was no significant difference between these rates in vaccinated and unvaccinated women, the study authors reported in a journal news release. About 2% of unvaccinated pregnant women and 1.5% of vaccinated pregnant women experienced miscarriage or stillbirth within seven days after a dose of either mRNA vaccine. The findings “concur with and add to the growing body of evidence that COVID-19 mRNA vaccines are safe during pregnancy,” claimed a commentary accompanying the new study. More information The US Centers for Disease Control and Prevention has more on COVID-19 vaccines. SOURCE: The Lancet Infectious Diseases, news release, 11 August 2022
