Overall 77.4% (3,833 out of 4,950; 95% confidence interval [CI] 76.2−78.6) of SARS-CoV-2 infections occurred in women who were unvaccinated at the date of onset of infection, with 11.5% (567 out of 4,950; 95% CI 10.6−12.4) in partially vaccinated women and 11.1% (550 out of 4,950; 95% CI 10.3−12.0) in fully vaccinated women.
Of the SARS-CoV-2 infections in pregnancy that occurred in unvaccinated women, 19.5% (748 out of 3,833; 95% CI 18.3−20.8) were associated with hospital admission, compared to 8.3% (47 out of 567; 95% CI 6.2−10.9) of those in partially vaccinated women and 5.1% (28 out of 550; 95% CI 3.5−7.4) of those in fully vaccinated women. A total of 2.7% (102 out of 3,833; 95% CI 2.2−3.2) of the SARS-CoV-2 infections in pregnancy that occurred in unvaccinated women were associated with a critical care admission, compared to 0.2% (1 out of 567; 95% CI 0.01−1.1) of those in partially vaccinated women and 0.2% (1 out of 550 cases; 95% CI 0.01−1.2) of those in fully vaccinated women.
While 77.4% (3,833 out of 4,950; 95% CI 76.2−78.6) of SARS-CoV-2 infections in pregnancy occurred in unvaccinated women, 90.9% (748 out of 823; 95% CI 88.7−92.7) of infections associated with hospital admission and 98.1% (102 out of 104; 95% CI 92.5−99.7) of infections associated with critical care admission, were in unvaccinated women.
A total of 2,364 babies have been born to women who had SARS-CoV-2 infection in pregnancy between 1 December 2020 and 31 October 2021. Of these, 2,353 were live births, of which 241 were preterm births (10.2%; 95% CI 9.1−11.6). Overall, 610 of the live births and 101 of the preterm births occurred within 28 days of the date of onset of the mother’s SARS-CoV-2 infection, giving a preterm birth rate among babies born within 28 days of SARS-CoV-2 infection of 16.6% (95% CI 13.7−19.8).
Meanwhile, 11 stillbirths were reported and 8 live births resulted in neonatal deaths (death within 28 days of birth), giving an extended perinatal mortality rate of 8.0 per 1,000 births following SARS-CoV-2 infection at any point in pregnancy and an extended perinatal mortality rate of 22.6 per 1,000 births within 28 days of the onset of maternal infection. All perinatal deaths following SARS-CoV-2 infection in pregnancy occurred in women who were unvaccinated at the time of SARS-CoV-2 infection.
For comparison, the background preterm birth rate during the pandemic (from March 1, 2020 to October 31, 2021) was 8.0% (95% CI 7.8−8.1) and the extended perinatal mortality rate was 5.6 per 1,000 births (95% CI 5.1−6.2). On the other hand, the preterm birth rates were 8.6% (95% CI 7.9−9.4) for women who received COVID-19 vaccination in pregnancy, and 8.2% (95% CI 7.0−9.6) for women who gave birth within 28 days of maternal vaccination. Meanwhile, extended perinatal mortality was 4.3 per 1,000 births (95% CI 2.9−6.4) in women who received COVID-19 vaccination in pregnancy, and 4.3 per 1,000 births (95% CI 1.9−9.2) in women who gave birth within 28 days of vaccination.