A new multinational study has found that COVID-19 vaccination during pregnancy, particularly with a booster dose, is associated with a reduced risk of preeclampsia. The research, conducted by the INTERCOVID Consortium, provides insights into potential benefits for pregnant individuals, independent of direct COVID-19 infection effects.
"COVID-19 vaccination during pregnancy, particularly with a booster dose, is associated with a reduced risk of preeclampsia."
Study Design and Scope
The study, published in eClinicalMedicine, analyzed data from 6,527 pregnant women across 18 countries. Data was collected between 2020 and 2022.
Researchers compared preeclampsia rates among vaccinated and unvaccinated women, meticulously accounting for the presence or absence of SARS-CoV-2 infection. This approach allowed them to assess the independent influence of vaccination status. The INTERCOVID Consortium includes institutions such as Ann & Robert H. Lurie Children's Hospital of Chicago and is led by University of Oxford researchers.
Key Findings
The study's comprehensive observations reveal several significant points:
- COVID-19 Infection Risk: COVID-19 infection during pregnancy was associated with a 45% increased risk of preeclampsia. This risk rose even higher, to 78%, among unvaccinated women who contracted the virus.
- Vaccination Impact:
- Vaccination with a booster dose reduced the overall odds of preeclampsia by 33%.
- Among women with pre-existing conditions such as diabetes, hypertension, or thyroid disorders, vaccination with a booster was associated with a 42% reduction in preeclampsia risk.
- The protective effect of vaccination remained consistent even after adjusting for key factors, suggesting potential benefits for preeclampsia prevention irrespective of infection status.
- Broader Maternal and Neonatal Outcomes: Vaccinated women also experienced lower odds of preterm delivery, maternal and perinatal morbidity, and mortality.
- Specifically, a booster dose was linked to a 33% protective effect for preterm birth, a 32% reduction in maternal morbidity and mortality, and a 29% reduction in severe perinatal morbidity and mortality.
Expert Perspectives and Implications
Professor José Villar, senior co-author and Principal Investigator of the INTERCOVID consortium, stated that the results suggest maternal vaccination may influence pathways involved in preeclampsia development, indicating a broader immunological or vascular benefit.
Dr. Jagjit S. Teji, a neonatologist at Lurie Children's and study co-author, noted that the findings support strengthening COVID-19 vaccination programs during pregnancy, emphasizing boosters, and ensuring equitable access to the vaccine globally.
Professor Paolo Ivo Cavoretto of IRCCS San Raffaele Hospital identified the study as the first large-scale, prospective evidence demonstrating that COVID-19 vaccination, particularly with boosters, may contribute to preeclampsia prevention. He highlighted that this protective effect was most significant among high-risk women with underlying health conditions.
Understanding Preeclampsia and Vaccination's Role
Preeclampsia affects an estimated 3% to 8% of pregnancies worldwide and is a leading cause of maternal and neonatal morbidity and mortality. While its exact origins are not fully understood, inflammation and vascular dysfunction are recognized contributors. These mechanisms overlap with those involved in COVID-19 infection.
The INTERCOVID findings support the hypothesis that vaccination may modulate immune and vascular pathways relevant to preeclampsia. This potentially offers protection even in the absence of a COVID-19 infection, aligning with existing evidence that some vaccines may have "non-specific" effects on immune regulation.