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Dr. Anthony Fauci (AP) Dr. Anthony Fauci (AP)

Dr. Anthony Fauci (AP)

Tom Kertscher
By Tom Kertscher August 18, 2021

Fauci didn’t doubt vaccine study; he cautioned against using it for choosing a booster

If Your Time is short

  • Dr. Anthony Fauci said he didn’t doubt the findings of a preliminary study on the effectiveness of the Moderna and Pfizer COVID-19 vaccines.

  • He cautioned not to use the study to make decisions about which vaccine to take for a booster shot.

  • The authors of the study urged more research to guide decisions such as when boosters should be taken and which vaccines should be given to unvaccinated people.

A Fox News Instagram post suggests that Dr. Anthony Fauci, the president’s top medical adviser, was hypocritical in how he assessed a study on the effectiveness of the Pfizer and Moderna COVID-19 vaccines.

"SELECTIVE SCIENCE? Fauci doesn’t trust new vaccine research as delta variant surges," read the post, which directed readers to a link to an article on Fox News’ website.

The post referred to remarks Fauci made in an interview with CBS about how to interpret a recent study on vaccine efficacy.

It was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

The text in the post is an inaccurate summary of what Fauci actually said. 

Fauci did not say he doesn’t trust the research findings, which indicated a disparity between the Moderna and Pfizer vaccines in their effectiveness at preventing COVID-19 infection.

Rather, Fauci pointed out that the preprint study is preliminary, and should not be used as a guide on which vaccine to choose for a booster. When it comes to booster shots, he said, people should get the same vaccine they received originally.

What Fauci said

The  Aug. 15 Fox News article referenced in the post was headlined: "Fauci dismisses study on delta efficacy between Moderna, Pfizer as guide for booster shots." 

The story reported on Fauci’s comments the same day on CBS’ "Face the Nation," which urged caution on acting on the results of the preliminary study by the Mayo Clinic in Minnesota.

A Fox spokesperson referred PolitiFact to Fauci’s comments on "Face the Nation," saying he "cast doubt" on the study.

Here’s the exchange between Fauci and "Face the Nation" host Nancy Cordes:

Cordes: "You know, you brought up the efficacy of the vaccines. I want to ask you about this new study out of Minnesota that suggested that the Moderna vaccine is actually more effective against the delta variant than the Pfizer vaccine. Does this study indicate that, if and when people do have to get booster shots, that they should go ahead and get a Moderna shot even if they got Pfizer the first time around?"

Fauci: "No, Nancy, not at all, because that study, first of all, it’s a preprint study, it hasn't been fully peer-reviewed. I don't doubt what they're seeing, but there are a lot of confounding variables in there about when one was started, the relative amount of people in that cohort, that's delta versus alpha. 

"Right now ... we're talking about boosters. We already implemented boosters for the immune-compromised. It's clear we want to make sure we get people, if possible, to get the boost from the original vaccine that they had. But remember, the original dose of the Moderna is about three times what the dose of the Pfizer is. So, you may have a difference in durability but, in general, the vaccines that have been approved for emergency use authorization — and, hopefully, will be approved for a full authorization in the sense of actual approval, hopefully that comes very soon — are all really highly effective in preventing severe disease."

What the Mayo Clinic study said

The Mayo Clinic study was posted Aug. 9 on a website for preprints. Preprint studies are preliminary, in that they have not yet been peer reviewed by other experts, and "should not be used to guide clinical practice," says a notice posted with the study.

The researchers compared the effectiveness of the Pfizer and Moderna vaccines in the Mayo Clinic Health System (Arizona, Florida, Iowa, Minnesota and Wisconsin) from January to July. 

Among the findings:

  • Both vaccines were "proven to reduce the burden of symptomatic disease, hospitalization and death related to SARS-CoV-2 infection. This study further supports the effectiveness of both vaccines in doing so, even despite the evolution of more transmissible viral variants."

  • For July, when the more contagious delta variant took hold across the U.S., the vaccines’ effectiveness for preventing infection dropped — to 76% for Moderna’s vaccine and 42% for Pfizer’s. That was the finding that the "Face the Nation" host alluded to.

  • While both vaccines "strongly protect against infection and severe disease, there are differences in their real-world effectiveness relative to each other and relative to prior months of the pandemic. Larger studies with more diverse populations are warranted to guide critical pending public and global health decisions, such as the optimal timing for booster doses and which vaccines should be administered to individuals who have not yet received one dose."

Our ruling

A Fox News Instagram post claimed that "Fauci doesn’t trust new vaccine research as delta variant surges."

That’s not an accurate interpretation of what he said. Fauci said he did not doubt the findings of a preliminary study on the effectiveness of the Moderna and Pfizer COVID-19 vaccines.

But he cautioned that the study’s findings are preliminary, and said they should not be used to make decisions about which vaccine to take for a booster shot. His position was consistent with the caveats the study authors noted.

We rate the post False.

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Fauci didn’t doubt vaccine study; he cautioned against using it for choosing a booster

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