Why Pfizer Stopped COVID Vax Trial

No randomized trial data are available for use of the COVID-19 shot in pregnant women, and Pfizer cut its pregnancy trial short.¹ But this doesn’t stop the U.S. Centers for Disease Control and Prevention from recommending COVID-19 injections for everyone 6 months and older, including “people who are pregnant, breastfeeding, trying to get pregnant now, or those who might become pregnant in the future.”²

“Not having any good data didn’t seem to bother the CDC,” Dr. Martin Makary, a professor at Johns Hopkins University School of Medicine, wrote in Tablet.³ He and a team of scientists petitioned the U.S. Food and Drug Administration to add a disclaimer to the shot’s label about the lack of trial data on its safety in pregnant women. The FDA declined, stating that this information wouldn’t be relevant.

Pregnant women, however, do need to know about the shot’s lack of testing during pregnancy — it’s the foundation of informed consent. They’d also likely be interested to know why Pfizer stopped its pregnancy trial early and has yet to make the results it did find public.

Pfizer Stopped COVID Jab Pregnancy Trial, Withholds Data

In February 2021, Pfizer launched a randomized, placebo-controlled, observer-blind study to evaluate the safety of its COVID-19 shot — BNT162b2 — in healthy pregnant women. The injections were set to take place between 24 and 34 weeks’ gestation, with participants randomized 1-to-1 to receive a COVID-19 shot or placebo.⁴ But while the study was initially set to enroll 4,000 women,⁵ Pfizer only signed up 349, then stopped enrollment entirely.⁶

“Most concerning,” Makary explained, “the pregnancy outcomes of those who participated in the trial, and their babies, are still not public today, nearly two years later.”⁷ Pregnant and breastfeeding women were excluded from Pfizer’s and Moderna’s phase III clinical trials,⁸ but in April 2021, CDC director Dr. Rochelle Walensky announced, “CDC recommends that pregnant people receive the COVID-19 vaccine.”⁹

The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) soon echoed this statement, recommending pregnant women get injected, as did the UK’s Royal College of Obstetricians and Gynecologists.¹⁰

So, as the months passed, hundreds of thousands of pregnant women globally rolled up their sleeves to receive the vaccine, despite the absence of any clinical trials. “The message from authorities was clear — the harm from COVID-19 infection outweighed any harms from the mRNA vaccine — but in truth, they couldn’t possibly have known,” noted Maryanne Demasi, Ph.D., a former medical scientist with the University of Adelaide and former reporter for ABC News in Australia.¹¹

Animal Studies Show Fetal Loss, Skeletal Variations

Pfizer’s product labeling suggested, “No vaccine-related adverse effects on female fertility, fetal development or postnatal development were reported.” But, Demasi reported, a freedom of information request from 2021 showed this was based on an animal study of just 44 rats, which showed concerning findings about fetal loss:¹²

“The study found the vaccine led to a statistically significant doubling in fetal loss (9.77% mRNA vs 4.09% saline), but Pfizer concluded that the difference between the two groups was “not biologically meaningful.”

The label also states that Pfizer’s mRNA vaccine was not tested for its potential to cause carcinogenicity (ability to cause cancer), genotoxicity (ability to damage genetic information), or impairment of male fertility.”

An animal study conducted by Moderna also showed a significant number of rats were born with skeletal variations after their mothers were injected with the COVID-19 shot while pregnant. But, according to Demasi, “Moderna concluded that the “Skeletal variations are structural changes that do not impact development or function of a developing embryo” and therefore “not considered adverse.””

Trial Stopped Because Many Pregnant Women Already Injected

Pfizer hasn’t publicly explained why its trial on pregnant women was stopped short, nor why the resulting data hasn’t been published. It’s possible they ended the trial because of unfavorable results. It wouldn’t be the first time.

However, in this case it appears the CDC’s widespread endorsement of COVID-19 shots for pregnant women — before the study was completed — may have negated the need for the trial altogether, at least from Pfizer’s perspective. As Makary put it:¹³

“In the case of the COVID vaccine trial in pregnant women, the trial may have been terminated not because the results were unfavorable, but because no data was needed. The medical and public health establishments had already made up their minds, declaring it safe and effective regardless of what the data was going to show. Why evaluate a product if the CDC and ACOG are already sold on the product?”

Demasi agreed. In fact, she published an email from Pfizer, in which the company admitted that enrollment for their trial significantly declined in the end of 2021, because health officials had already given the shot their seal of approval. Because so many pregnant women had already gone ahead and gotten the shot, due to the government’s endorsement, there was no reason to move ahead with the study. Demasi published Pfizer’s email response, which reads:¹⁴

“In the fourth quarter of 2021, enrollment was stopped in C4591015 Study (a Phase 2/3 placebo controlled randomized observer-blind study to evaluate the safety, tolerability, and immunogenicity of BNT162b2 against COVID-19 in healthy pregnant women 18 years of age and older). This study was developed prior to availability or recommendation for COVID-19 vaccination in pregnant women.

The environment changed during 2021 and by September 2021, COVID-19 vaccines were recommended by applicable recommending bodies (e.g., ACIP in the U.S.) for pregnant women in all participating/planned countries, and as a result the enrollment rate declined significantly.

With the declining enrollment, the study had insufficient sample size to assess the primary immunogenicity objective and continuation of this placebo controlled study could no longer be justified due to global recommendations. This proposal was shared with and agreed to by FDA and EMA.”

As for the lack of published data, Pfizer stated it doesn’t have it:¹⁵

“Pfizer does not yet have a complete data set from the maternal immunization study, C4591015. Pfizer and BioNTech plan to complete the analysis of the clinical trial C4591015 and share it with global public health regulators and seek publication or presentation as is our standard practice.

It is important to note that relevant real-world evidence on the use of COVID-19 vaccines in pregnant women has been presented and published numerous times by various parties in multiple journals and forums.”

Natural Immunity Is Still Being Ignored

Not only does ACOG “strongly recommend” that pregnant women get a COVID-19 shot, but they also recommend a booster dose.¹⁶ “Vaccination may occur in any trimester, and emphasis should be on vaccine receipt as soon as possible to maximize maternal and fetal health. This recommendation applies to both primary series and booster vaccination,” ACOG states.¹⁷