Two researchers say countries should halt the administration of COVID-19 vaccines to pregnant and breastfeeding women after re-analyzing a study performed by Centers for Disease Control and Prevention (CDC) researchers.
The study in question, published in the New England Journal of Medicine in April, has been used by the CDC and health agencies in other countries to justify vaccination recommendations to pregnant women and new mothers.
“A U.S. study of over 35,000 women who were pregnant and had an mRNA COVID-19 vaccine showed that the side effects following vaccination were very similar in those who were pregnant when compared to those who were not,” the Australian government says in a guide (pdf) to COVID-9 vaccination for women.
The study, though, was corrected last month after concerns were raised by a researcher in Belgium. The CDC scientists acknowledged they should have made clear that they could not accurately calculate a risk estimate for miscarriages because follow-up data was not yet available for most of the women.
The correction resolved some of the issues, but there are still more, according to Dr. Simon Thornley, a senior lecturer in the University of Auckland’s Section of Epidemiology and Biostatistics, and Dr. Aleisha Brock, another researcher in New Zealand.
“The article’s conclusions haven’t changed substantially as we believe is warranted from our re-analysis of the association related to early exposure to the vaccine in pregnancy, which indicates a substantially increased risk from background,” Thornley told The Epoch Times in an email.
Thornley and Brock re-analyzed the data and calculated the incidence of miscarriages in the first trimester was actually 82 percent to 91 percent in a paper (pdf) published in Science, Public Health Policy, and the Law.
Of the 827 pregnancies reported through the V-Safe registry, operated by the CDC, 712 resulted in a live birth. Nearly all of them were among women who were vaccinated in the third trimester. Of the other pregnancies, 104 resulted in miscarriage. Most of those occurred before 13 weeks of gestation.
Using data from the study and several estimates, the New Zealand researchers calculated that spontaneous abortions occurred in 81.9 percent to 91.2 percent of the women who were vaccinated before 20 weeks of gestation.
“We question the conclusions of the Shimabukuro et al. study to support the use of the mRNA vaccine in early pregnancy, which has now been hastily incorporated into many international guidelines for vaccine use, including in New Zealand,” the researchers said.
“The assumption that exposure in the third trimester cohort is representative of the effect of exposure throughout pregnancy is questionable and ignores past experience with drugs such as thalidomide. Evidence of safety of the product when used in the first and second trimesters cannot be established until these cohorts have been followed to at least the perinatal period or long-term safety determined for any of the babies born to mothers inoculated during pregnancy,” they added.
Pfizer, it was noted, says on its vaccine’s label that the available data on the vaccine “administered to pregnant women are insufficient to inform vaccine-associated risks in pregnancy.”
The CDC researchers concluded their findings didn’t show any obvious safety signals among pregnant women who received the Pfizer or Moderna vaccines. They said their findings did not necessarily represent the position of the CDC, but the agency links to the study on its website and used it to promote vaccination in pregnant women, and a query sent to the study’s main author was forwarded to a CDC spokeswoman, who pointed to an August statement regarding the study.
“We are aware that some of the data has been used to calculate a higher rate of miscarriage,” the agency said at the time. “This is not an appropriate calculation based on the data available because more than 1,000 pregnancies were ongoing, and their outcome data was not available at the time of the report. About 10–25% of known pregnancies end in miscarriage. CDC experts will continue to study the effects of COVID-19 vaccination on pregnancies and closely monitor any safety concerns.”
The spokeswoman also referred to two research letters regarding pregnant women and COVID-19 vaccines that have since been published. One was from CDC researchers who said the estimated risk of miscarriages following vaccination was within the range of total miscarriages, regardless of cause. The other, from outside researchers, studied CDC data and reached a similar conclusion.
“These findings are reassuring and can help inform discussions about COVID-19 vaccination during pregnancy between pregnant people and their healthcare providers,” the spokeswoman said, adding that “growing evidence about the safety and effectiveness of COVID-19 vaccination during pregnancy demonstrates that the benefits of receiving a COVID-19 vaccine outweigh any known or potential risks.”
Hong Sun, the researcher in Belgium who pointed out the original problem with the early CDC study that prompted a correction, told The Epoch Times that he didn’t agree with Thornley and Brock’s re-analysis.
“While I also suggest removing the 700 cases from the dominator, I also consider such an equation is no longer valid, in other words, it is not possible to calculate an accurate rate of spontaneous abortion rate with the given data, and this view is acknowledged by CDC. In [the CDC’s] follow-up study, a more reasonable rate is calculated and I consider it is a fair estimation,” he said in a LinkedIn message.
The CDC recommends pregnant women get a COVID-19 vaccine, with few exceptions.
Thornley is not so sure. He said the studies do show no increased risk in getting the vaccine but there are some questions regarding the selection of participants.
“There are at least some questions related to the selection of participants which are an issue for case-control studies, compared to a cohort analysis such as that found in the CDC data. The data which addresses this issue of safety, particularly with regard to exposure to mRNA vaccines early in pregnancy is sparse, from published evidence, and I would question anyone who believes it is in any way conclusive,” he told The Epoch Times.
“Since the risk of fatality or severe outcome following COVID-19 infection is generally extremely low for younger people, including those who are pregnant, we caution against the use of the vaccine, given the substantial uncertainty that exists,” he added.