The claim: 80,000 pages of Pfizer data show the vaccine has a 12% efficacy rate, harms fetuses
As the spring saw another surge of coronavirus cases across the country, healthcare officials are urging people to get vaccinated. But some social media posts are spreading false claims that the Pfizer vaccine is both ineffective and dangerous.
“Pfizer data released today. 80,000 pages. Pfizer knew vaccine harmed the fetus in pregnant women, and that the vaccine was not 95% effective,” reads an Instagram post shared May 4. “Pfizer data shows it having a 12% efficacy rate.”
These claims were made two days after more than 80,000 pages of Pfizer COVID data was made public. The data was released as part of an ongoing Freedom of Information Act lawsuit, according to Abigail Capobianco, a spokesperson for the Food and Drug Administration
The post generated over 4,000 likes in less than a week – but has since apparently been deleted. Similar claims have amassed hundreds of interactions on Facebook, Twitter and Instagram.
But the claim is wrong on multiple fronts.
USA TODAY could not verify whether the claimed 12% efficacy rate was in the 80,000 pages Pfizer released. None of the social media claims have provided documentation showing that figure. But multiple experts told USA TODAY the claims about the vaccine’s low efficacy rate stem from misinterpretations of Pfizer’s 2020 phase three clinical trial.
The trial actually showed an efficacy rate of 95%. Extensive Pfizer research studies on the efficacy of the Pfizer vaccine do not validate the 12% figure in the claim either.
It is also unclear from which document the claim about the vaccine harming fetuses originates. But multiple studies and CDC reports show the Pfizer vaccine is safe for fetuses.
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USA TODAY reached out to the social media users who shared the claim for comment.
12% calculation of efficacy rate based on misinterpretation of data
It’s not clear where the 12% efficacy rate comes from, since both the FDA and Pfizer declined to comment on whether it was in the release. But experts told USA TODAY the incorrect figure is based on a misinterpretation of data in a 2020 Pfizer clinical trial.
The most recent version of this claim stems from an April 3 Substack article published by investigative reporter Sonia Elijah with the headline, “Was Pfizer’s 95% vaccine efficacy fraudulent all along?,” according to Jeffrey Morris, the director of the Division of Biostatistics at the University of Pennsylvania.
In the article, Elijah references a 53-page December 2020 Pfizer FDA briefing, which was released to the public one week before the advisory committee meeting on December 10 of that year, Morris said. It is not part of the recent Pfizer document release.
Fact check: Fabricated story that Pfizer CEO was arrested for COVID-19 vaccine fraud
The phase three trial in the briefing involved close to 38,000 participants who were separated into two groups: half who received two doses of the Pfizer vaccine and half who received a placebo.
Out of this group, 3,410 people, 1,594 in the vaccine group and 1,816 in the placebo group–were suspected of having COVID but were unconfirmed, meaning the participants had symptoms after they had received the injections, but did not have a positive PCR test, Morris said.
One hundred sixty-two participants in the placebo group and 8 participants from the vaccine group tested positive for COVID-19 after the injections.
The vaccine efficacy rate, calculated by dividing only the participants who tested positive for the virus in both groups, came out to be 95%. Elijah claimed that the real vaccine efficacy rate should have been 12%, basing her calculation off participants in the suspected but unconfirmed group.
The 12% claim later became a viral take, according to Morris.
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But her interpretation of the data is wrong since she included people who had symptoms of COVID-19 but not the virus itself, Dr. Howard Forman, a professor of public health policy, management and economics at Yale University, told USA TODAY.
“She has shown that the vaccine seems to have very low efficacy for non-COVID illness, which is precisely what we would expect,” Forman said. “The vaccine does not work against a non-COVID cough. Or a non-COVID headache.”
The suspected but unconfirmed cases should not be figured into the vaccine efficacy data analysis, Forman said.
USA TODAY reached out to Elijah for comment.
Pfizer vaccine is effective against COVID-19
Numerous peer review studies and real-world examples have shown the effectiveness of the Pfizer vaccine, according to Dr. Amesh Adalja, infectious disease specialist at Johns Hopkins University.
In a 2021 study, researchers found that Pfizer vaccine efficacy against Covid-19 was 91.3% among trial participants 12 years and older “without evidence of previous SARS-CoV-2 infection” through a period of six months.
Another study published that same year found that the Pfizer vaccine was more than 90% effective at preventing COVID-19 in children ages 5-11.
Fact check: Vaccines protect against contracting, spreading COVID-19
Research has also shown that the vaccine’s protection against the virus wanes over time and should be complemented with a booster. A 2022 study found that patients who only received two shots of the Pfizer vaccine were limited in their protection against the Omicron variant compared to those who received three shots.
The risk arising from not getting the vaccine is much greater than being vaccinated, Scott Pauley, a spokesperson for the CDC, previously told USA TODAY. A 2021 CDC report found that people were five times more likely to have COVID-19 if they were unvaccinated and had prior infection.
Vaccines are safe for fetuses
It is unclear where the claim about the vaccine harming fetuses originates. But to date, the FDA and CDC have not identified any safety concerns about harm or harm to fetuses following administration of any of the COVID-19 vaccines, said Capobianco, the FDA spokesperson.
A 2021 CDC report found that receiving the COVID-19 vaccine during pregnancy was not associated with increased risk for preterm birth or small-for-gestational-age at birth.
Fact check: No evidence Pfizer, Moderna COVID-19 vaccines cause miscarriage
A CDC report published in 2022 also found that patients who have received two doses of the COVID-19 vaccine and are pregnant may help “prevent COVID-19 hospitalization among infants” less than six months old.
There are pregnancy complications women can face if they are exposed to COVID-19, such as “delivering a preterm (earlier than 37 weeks) or stillborn infant,” according to the CDC.
“COVID-19 vaccination is recommended for people who are pregnant, breastfeeding, trying to get pregnant now or might become pregnant in the future,” reads the agency’s website.
Our rating: False
Based on our research, we rate FALSE the claim that 80,000 pages of Pfizer data show the vaccine has a 12% efficacy rate.
USA TODAY could not verify whether the 12% figure was in the 80,000 pages Pfizer released May 2. But experts said the 12% figure stems from an incorrect interpretation of a 2020 Pfizer clinical trial document.
The actual efficacy rate of the vaccine in the trial showed it was 95%. No research studies validate the 12% efficacy rate of the Pfizer vaccine. Multiple studies also show that the Pfizer vaccine is safe for fetuses.
Our fact-check sources:
- Kit Longley, May 6, Email exchange with USA TODAY
- Jeffrey Morris, May 6, Phone interview with USA TODAY
- Amesh Adalja, May 6, Phone interview with USA TODAY
- Howard Forman, May 6, Phone interview with USA TODAY
- Abigail Capobianco, May 6, Email exchange with USA TODAY
- COVID-19 Data Science, accessed May 6, Do the recent 80k pages of Pfizer documents released really show vaccine efficacy was only 12%?
- ABC10, Nov. 19, 2021, FDA says 55 years to process request for extensive vaccine data under Freedom of Information Act
- NBC5 Chicago, May 7, As New Omicron Subvariant Spreads, Here Are the Symptoms to Watch For
- Food and Drug Administration, Dec. 10, 2020, Vaccines and Related Biological Products Advisory Committee Meeting
- USA TODAY, Nov. 10. 2021, Fact check: Fabricated story that Pfizer CEO was arrested for COVID-19 vaccine fraud
- Public Health and Medical Professionals for Transparency, accessed May 9, Pfizer’s documents
- New England Journal Medicine, Dec. 10, 2020, Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine
- New England Journal, Sept. 15, 2021, Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine through 6 Months
- New England Journal, Nov. 9, 2021, Evaluation of the BNT162b2 Covid-19 Vaccine in Children 5 to 11 Years of Age
- USA TODAY, Dec. 2, 2021, Fact check: COVID-19 vaccines safe for children, not linked to deaths
- Science, Jan. 18, Neutralization of SARS-CoV-2 Omicron by BNT162b2 mRNA vaccine–elicited human sera
- Yale Medicine, Feb. 24, 2021, Comparing the COVID-19 Vaccines: How Are They Different?
- Centers for Disease Control and Prevention, Jan. 7, Receipt of COVID-19 Vaccine During Pregnancy and Preterm or Small-for-Gestational-Age at Birth — Eight Integrated Health Care Organizations, United States, December 15, 2020–July 22, 2021
- Centers for Disease Control and Prevention, Feb. 18, Effectiveness of Maternal Vaccination with mRNA COVID-19 Vaccine During Pregnancy Against COVID-19–Associated Hospitalization in Infants Aged <6 Months — 17 States, July 2021–January 2022
- Centers for Disease Control and Prevention, March 3, Pregnant and Recently Pregnant People
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