A health care worker holds a vial of Pfizer-BioNtech Covid-19 vaccine in Miramar, Florida on December 14, 2020 ( AFP / Chandan Khanna)

Vaccination does not increase the likelihood of Covid-19 infection

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Online articles and social media posts use studies on Covid-19 vaccination to claim that the shots make people more vulnerable to contracting the disease. But experts say the claims misrepresent the research, and that unvaccinated people are at greater risk of infection, hospitalization and death.

"UPDATED. 'If you get the Pfizer vax, you're more likely to get COVID': Industry analyst flags FDA study," says the headline of an article on lifesitenews.com, which has been banned on both Facebook and YouTube for spreading Covid-19 misinformation.

A screenshot of an article taken on October 11, 2021

Although Covid-19 is taking a high toll on the unvaccinated, some Americans are reluctant to receive the shots -- hesitancy that is made worse by a wave of misinformation that has spread about both the disease and the vaccines.

A video embedded in the article that makes similar claims and also appeared on BitChute, and was linked to on Twitter here and here.

The article cites an alleged whistleblower's claim that research on the declining efficacy of the Pfizer-BioNTech vaccine -- summarized in a briefing document from the US Food and Drug Administration (FDA) -- shows that receiving the vaccine increases the odds of contracting Covid-19.

"That claim is false and misleading," an FDA spokesperson told AFP, noting that in the video, the first example of the text highlighted by the alleged whistleblower has been "taken out of context as it refers to waning immunity over time and the possible contributing factor of the Delta variant" of SARS-CoV-2, the virus that causes Covid-19.

"The FDA conducted a thorough evaluation of the data and information submitted in the Biologics License Application (BLA) for Comirnaty before making a determination that the vaccine is safe and effective in preventing Covid-19 in individuals 16 years of age and older," the spokesperson said, referring to the name under which regulators approved the vaccine.

Pfizer said the claims about vaccination increasing the likelihood of contracting Covid-19 misrepresent research the company submitted to the FDA.

"No, the study did not find that receiving the Pfizer-BioNTech Covid-19 vaccine increases your chances of getting Covid-19," Pfizer spokeswoman Keanna Ghazvini said.

What the research did find is that "over time, there is a modest decline in vaccine efficacy -- a measure of how well the vaccine prevents disease, in this case Covid-19," Ghazvini said.

She added that "it's important to note that this is expected to occur over a period of time following vaccination or infection, and it's something we see in other vaccines. This also is where the need for booster shots comes in -- to provide a 'boost' to the immune system."

A study led by Kaiser Permanente and published in The Lancet found the Pfizer-BioNTech vaccine was less effective after six months, but still offered protection against severe illness.

Sara Tartof, an infectious disease epidemiologist and lead author of the study, described the online claims about the vaccine as "misleading and false."

"Increased incidents of infections, hospitalizations and deaths are much more highly correlated to vaccine refusal than vaccination with the Pfizer Covid-19 vaccine. Full vaccination with Pfizer vaccine substantially decreases infections and severe disease due to Covid-19," she said.

And Alison Galvani, the director of the Yale Center for Infectious Disease Modeling and Analysis, said that "regardless of waning immunity, people who have been vaccinated are much less likely to become infected, hospitalized or die from Covid-19."

"The waning of immunity is a reason to receive a booster dose, not to refuse vaccination altogether," she added.

- 'Patently false' -

A blog post published on "The Conservative Treehouse" website on October 3 made similar claims, saying vaccinated people are more susceptible to infection by SARS-CoV-2 variants, and that they account for more deaths from the Delta variant than the unvaccinated.

A screenshot of a blog post taken on October 11, 2021

To support this claim, the article relied on the results of a study on antibody-resistant SARS-CoV-2 variants and a table taken from an official UK public health report.

But the conclusions presented by the post -- including that "vaccinated individuals are more susceptible to Covid variant infections than unvaccinated" -- are incorrect.

"This is a misinterpretation of our study," said Charles Chiu, senior author of the study and professor of medicine in the Division of Infectious Diseases at the University of California, San Francisco.

Instead, the study shows that infections by "antibody-resistant variants" -- such as the Delta variant -- are overrepresented among vaccine breakthrough cases.

"Vaccination prevents the vast majority of infections, but the small subset of vaccinated individuals who had breakthrough infections at that time were, not surprisingly, more likely to be infected by these antibody-resistant variants," he said, while "infections in unvaccinated individuals generally reflect the overall distribution of variants circulating in the community at the time."

"Our study also showed that vaccination reduces viral loads in breakthrough cases, especially in individuals who are asymptomatic. By reducing transmission, vaccination thus would decrease the probability of emergence of new variants with resistant mutations," Chiu said.

The California Department of Public Health that provided vaccine breakthrough data for the San Francisco study also said that "the claim that vaccinated individuals are more susceptible to SARS-CoV-2 variant infections (or Covid-19) than unvaccinated individuals is not correct, in other words this is patently false."

The blog post also says that a table from a Public Health England report shows that most people who die from the Delta variant are fully vaccinated, suggesting that the shots are ineffective.

A screenshot taken on October 7, 2021 shows official Public Health England official data misrepresented in a blog post

A spokesperson for the UK Health Security Agency said that, in the context of a population with high vaccine coverage such as that in the United Kingdom, it is expected that a large proportion of cases would occur in vaccinated individuals, even with highly effective shots -- simply because a larger proportion of the population is vaccinated than unvaccinated.

A similar claim misrepresenting official English data was debunked by AFP Fact Check here.