Vaccination provides effective protection against increased risk of pregnancy complications due to COVID-19 Omicron variant
- 3 min. read ▪ Published
The global network led by the Oxford Maternal and Perinatal Health Institute (OMPHI) at the University of Oxford, which included Robert Gunier, Stephen Rauch, and Brenda Eskenazi at the UC Berkeley School of Public Health’s Center for Environmental Research and Community Health (CERCH), has published new research in The Lancet that showed that vaccination is an effective protection against the increased risk of pregnancy complications from the COVID-19 Omicron variant.
The paper presents results of the “2022 INTERCOVID Study,” conducted in 41 hospitals across 18 countries. To evaluate the impact of the COVID-19 Omicron variant on maternal and neonatal outcomes the researchers studied 1,545 pregnant women diagnosed with the variant and 3,073 non-diagnosed, concomitant pregnant women as controls. The study was conducted between 27 November, 2021, and 30 June, 2022, during which time Omicron was the variant of concern. Vaccine effectiveness against the variant was also assessed.
The COVID-19 Omicron variant during pregnancy was associated with increased risks of maternal morbidity, severe pregnancy complications, and hospital admission, especially among symptomatic and unvaccinated women. In particular, the risk of preeclampsia was increased among women with severe symptoms. Obese/overweight women with severe symptoms were at the highest risk for maternal morbidity and severe complications.
Vaccinated women were well protected against severe COVID-19 symptoms and complications and had a very low risk of admission to an intensive care unit. Prevention of severe COVID-19 symptoms and complications requires women to be completely vaccinated, preferably with a booster dose as well.
In the study, mRNA vaccines were most effective in preventing severe COVID-19 symptoms and complications, although viral vector vaccines with a booster also provided adequate protection – for at least 10 months after the last dose for both mRNA vaccines and viral vector vaccines with a booster.
“In this multinational study, there was no evidence of an increased risk of pregnancy complications or adverse perinatal events associated with COVID-19 vaccines, even if the first vaccination was received during pregnancy,” said Robert Gunier, associate researcher at UC Berkeley School of Public Health’s Center for Environmental Research and CommunityHealth (CERCH) and lead statistician on the paper. “Unvaccinated pregnant women with a COVID-19 diagnosis while Omicron was the variant of concern had more than three times the risk of severe complications compared to unvaccinated women without a COVID-19 diagnosis. COVID-19 vaccines were highly effective at preventing severe symptoms and complications when pregnant women were completely vaccinated (>70% effectiveness) or had a booster vaccination (>90% effectiveness).”
“The study clearly indicates the need for a complete vaccination course during pregnancy, preferably with a booster, to provide protection for at least 10 months after the last dose. Antenatal services worldwide should strive to include vaccination against COVID-19 in the routine care of pregnant women,” said José Villar, Professor of Perinatal Medicine at the University of Oxford, who co-led INTERCOVID 2022.