A groundbreaking multinational study conducted by the INTERCOVID Consortium, which includes the Ann & Robert H. Lurie Children’s Hospital of Chicago, has revealed that COVID-19 vaccination during pregnancy, especially when paired with a booster dose, significantly lowers the risk of developing preeclampsia. This serious pregnancy complication can be life-threatening, and the findings offer new insights into its prevention, independent of the direct effects of COVID-19 infection.
Published in the journal eClinicalMedicine, the study titled “COVID-19 Vaccination Status During Pregnancy and Preeclampsia Risk: The Pandemic-Era Cohort of the INTERCOVID Consortium” analyzed data from 6,527 pregnant women across 18 countries, enrolled between 2020 and 2022. Researchers compared vaccinated and unvaccinated women, both with and without SARS-CoV-2 infection, to assess how vaccination status influenced preeclampsia rates.
Key Findings and Expert Opinions
Dr. Jagjit S. Teji, a neonatologist at Lurie Children’s and Clinical Assistant Professor of Pediatrics at Northwestern University Feinberg School of Medicine, emphasized the importance of these findings. “Our results support the importance of strengthening COVID vaccination programs during pregnancy, emphasizing boosters and ensuring that pregnant people across the world have equitable access to the vaccine,” he stated. “We offer evidence from the first large study suggesting that COVID vaccination may protect against one of the most serious pregnancy complications.”
- COVID-19 infection during pregnancy was associated with a 45% increased risk of preeclampsia, which rose to 78% among unvaccinated women.
- Vaccination reduced the overall odds of preeclampsia among women receiving a booster dose by 33%, statistically significant.
- Among women with pre-existing health conditions such as diabetes, hypertension, or thyroid disorders, vaccination with a booster cut preeclampsia risk by 42%, statistically significant.
Professor José Villar, the senior co-author of the study and Principal Investigator of the INTERCOVID consortium from the Nuffield Department of Women’s & Reproductive Health, University of Oxford, added, “These results go beyond the known benefits of COVID-19 vaccination in pregnancy. We now have evidence that maternal vaccination may influence pathways involved in preeclampsia development, suggesting a broader immunological or vascular benefit of vaccination.”
Understanding Preeclampsia and its Global Impact
Preeclampsia affects 3% to 8% of pregnancies worldwide, depending on the risk profile, and remains a leading cause of maternal and neonatal morbidity and mortality. The exact origins of preeclampsia are still unknown, but inflammation and vascular dysfunction are known contributors—mechanisms that overlap with COVID-19 infection. The INTERCOVID findings suggest that vaccination may modulate immune and vascular pathways involved in preeclampsia, potentially offering protection even in the absence of COVID-19 infection.
This aligns with growing evidence that some vaccines may have beneficial “non-specific” effects on immune regulation. The study’s results indicate that vaccinated women also experienced lower odds of preterm delivery, maternal and perinatal morbidity, and mortality. Specifically, among women who received a booster dose, the protective effect for preterm birth was 33%, maternal morbidity and mortality was 32%, and severe perinatal morbidity and mortality was 29%, all statistically significant.
The Global Effort and Future Implications
The INTERCOVID consortium includes over 40 hospitals across 18 countries, reflecting a truly global effort to understand maternal and perinatal outcomes during the pandemic. This collaboration underscores the importance of international cooperation in addressing public health challenges.
Ann & Robert H. Lurie Children’s Hospital of Chicago, a nonprofit organization, plays a pivotal role in this research. As the only independent, research-driven children’s hospital in Illinois, Lurie Children’s is devoted to providing exceptional care and advancing pediatric medicine through the Stanley Manne Children’s Research Institute. The hospital serves as the pediatric training ground for Northwestern University Feinberg School of Medicine and is consistently ranked as one of the nation’s top children’s hospitals by U.S. News & World Report.
As the world continues to grapple with the COVID-19 pandemic, these findings offer a promising avenue for improving maternal health outcomes. The study’s authors advocate for the strengthening of vaccination programs for pregnant women, emphasizing the need for equitable access to vaccines globally. This could potentially lead to a significant reduction in preeclampsia cases, improving the health and safety of mothers and their babies worldwide.
