HHS justifies decision to stop recommending Covid shots during pregnancy with studies supporting the shots' safety

Politico

10-06-2025

The Department of Health and Human Services is circulating a document on Capitol Hill to explain its decision to remove the Covid-19 vaccine recommendation for pregnant women — citing studies that largely found the shot is safe.
The document, which HHS sent to lawmakers days before Secretary Robert F. Kennedy Jr. announced his plan to fire the panel that advises the CDC on immunizations, says that studies have shown that women who got the vaccine during pregnancy had higher rates of various complications. And it claims that 'a number of studies in pregnant women showed higher rates of fetal loss if vaccination was received before 20 weeks of pregnancy,' footnoting a research paper on vaccination during pregnancy.
But Dr. Maria P. Velez of McGill University, the lead author of one of the studies, told POLITICO in an email that 'the results of our manuscript were misinterpreted.'
The 2023 study shows a slightly higher rate of miscarriages among women who were immunized against Covid-19 during their pregnancies. But, Velez said, that after adjusting for 'variables that can confound a crude association,' like 'age, rurality, neighbourhood income quintile, immigration status, comorbidity' and other factors that could affect the outcome, Canadian researchers found 'no association between SARS-CoV-2 vaccination and an increased risk of miscarriage.'
Raw numbers don't account for significant differences among the groups being compared — such as underlying conditions and when during pregnancy the people were vaccinated, said Katelyn Jetelina, an epidemiologist who's consulted for the Centers for Disease Control and Prevention. Scientists, including the Canadian researchers, use statistical methods to adjust for those factors, she said, which is how they determined the vaccine wasn't associated with miscarriage.
In a statement, HHS spokesperson Andrew Nixon pointed to the raw study data, which showed a slightly higher rate of miscarriage in the first half of pregnancy for women who were vaccinated against Covid compared with those who weren't.
'The underlying data speaks for itself — and it raises legitimate safety concerns,' he said. 'HHS will not ignore that evidence or downplay early pregnancy loss.'
Nixon added that HHS and the CDC encourage people to talk to their providers 'about any personal medical decision.'
Vaccine researchers and obstetricians criticized the decision to remove the recommendation for pregnant women, and researchers cited in the HHS document largely dismissed any connection between Covid vaccination and miscarriages.
'Given that COVID-19 infection during pregnancy is associated with serious maternal and neonatal morbidity, the current study can inform healthcare providers, pregnant women and those considering a pregnancy about the safety of SARS-CoV-2 vaccination in relation to miscarriage risk,' Velez and her co-authors wrote in the study. That research was based on health-system data from Ontario, Canada, and aligned with similar population studies in the U.S., Scotland and Norway.
Similarly, HHS cited an April 2022 study in its document concerning mRNA vaccination in people undergoing in-vitro fertilization, which also found no adverse effects on conception rates or on early pregnancy outcomes.
'Administration of COVID-19 mRNA vaccines was not associated with an adverse effect on stimulation or early pregnancy outcomes after IVF,' the New York City-based researchers at the Icahn School of Medicine at Mount Sinai and Mount Sinai West hospital wrote in the study. 'Our findings contribute to the growing body of evidence regarding the safety of COVID-19 vaccination in women who are trying to conceive.'
The HHS document also includes an incorrect link for that study, instead leading to a different study — also cited in HHS' document — by Israeli researchers that found the vaccine 'appears to be safe during pregnancy,' with no increase in preterm labor or in newborns with low birth weight.
That February 2022 study did note a possible increase in preterm birth rates for women vaccinated during the second trimester, and the authors suggested future investigations of outcomes based on the timing of immunization.
HHS' assertion about significant risks to pregnant women 'contradicts the bulk of published studies,' said Dr. Paul Offit, an expert who has served as an outside adviser on vaccines to the FDA and the CDC.
HHS deviated from past practice when it changed the Covid vaccine guidance last month, announcing the decision without the endorsement of an existing outside panel of expert advisers.
Dr. Steven Fleischman, president of the American College of Obstetricians and Gynecologists, told POLITICO at the time that he was disappointed by HHS' decision, and pointed to data showing that newborns can benefit from maternal antibodies from the vaccine for protection from Covid.
'In fact, growing evidence shows just how much vaccination during pregnancy protects the infant after birth, with the vast majority of hospitalized infants less than 6 months of age — those who are not yet eligible for vaccination — born to unvaccinated mothers,' Fleischman said.