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Is the Pfizer booster shot necessary to beat the delta variant? An expert weighs in

Pfizer's recent push to add a booster shot to its COVID-19 vaccination protocol seems to be at odds with what many people understood about the drug's effectiveness. And, as William Brangham reports, it has also prompted real concern among healthcare professionals. Dr. Kirsten Bibbins-Domingo, a professor of epidemiology and biostatistics at the University of California joins us to discuss.

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  • Judy Woodruff:

    Even before its meeting today with the FDA, Pfizer's recent push to add a booster shot to its COVID-19 vaccination protocol seemed to be at odds with what many people thought they had understood about the drug's effectiveness.

    And, as William Brangham reports, it also has prompted real concern among health care professionals.

  • William Brangham:

    That's right, Judy.

    Late last week, Pfizer said it recommended adding a third so-called booster shot to its original two-shot vaccine at about six months after initial immunization. The company said that's when its own internal study showed the vaccine's initial protections began to decline.

    But those findings contradicted other research. And many public health officials disagreed whether boosters were necessary or appropriate, especially given that three-quarters of the world's population has not had a single dose just yet.

    One of those weighing in is Dr. Kirsten Bibbins-Domingo. She's a professor of epidemiology and biostatistics at the University of California at San Francisco.

    Dr. Bibbins-Domingo, great to you have back on the "NewsHour."

    So this Pfizer announcement came — it caused a good deal of confusion, because what we had been told thus far — I mean, Pfizer said, because of the Delta variant, we're going to work on this booster.

    But we have been lead to believe thus far that the vaccines, including Pfizer's, are quite protective against the Delta variant. Help us unpack all this.

  • Kirsten Bibbins-Domingo:


    It turns out that both of those things are true. And I think the question is not whether Pfizer should be constantly looking to understand whether their vaccines are working in all people as well as it possibly can or whether a booster might not be necessary in a specific group of people, let's say older adults.

    The question really is, right now, do we have confidence in the vaccines? We absolutely do. Does this Pfizer vaccine work against the Delta variant? It absolutely does. And is the most important thing that we need to do now making sure those people who don't have any doses, making sure that they get their first and second dose? That's absolutely the most important thing now.

    So both things are true. We need to look for the possibility for boosters in the future, but stay very focused on getting everyone vaccinated today.

  • William Brangham:

    Let's talk about that global vaccine response in a secretary.

    But, first off, this issue that Pfizer is saying that there does seem to be some waning of protection after six months, should that alarm people? Because, on its face, it sounds alarming.

  • Kirsten Bibbins-Domingo:


    It sounds alarming. And I think that is what leads many public health people to be worried that it's going to distract people from the actual issue at hand, which is getting vaccinated.

    It turns out all the reports from Israel, which is where a lot of this data is coming from, actually suggest that the Pfizer vaccine is 93 percent effective against preventing against hospitalizations with severe disease and death. That is in the face of the Delta variant, so highly effective in preventing severe disease and death against the variant.

    But it may not work in exactly that same way in all people. And so I think many people who are willing to think about whether a booster is necessary are really asking the question, in whom is it necessary? It might be that those who have more compromised immune systems or in older people, who oftentimes don't mount as effective an immune response, might need an extra boost later on.

    But, right now, every study that's been published, all the data that we have available to us suggests that the Pfizer vaccine, the Moderna vaccine is actually quite effective at the Delta variant.

  • William Brangham:

    OK, so let's talk a bit, as you mentioned before, about what the U.S. can do to help spread this global vaccination campaign.

    We know the U.S. has secured enough vaccine for every man, woman and child in the United States and still have tens of millions, perhaps hundreds of millions of doses left over. Should we be doing more to get more vaccine into all those nations that need it?

  • Kirsten Bibbins-Domingo:


    I mean, I think the big issue, when we look at the surges around the world, when we look even at the surges in the U.S., is that there are people who are not yet vaccinated. And so, even though we have a little more than half of the people in the U.S. vaccinated, it is absolutely essential that we stay focused on getting the rest of the people in the U.S. vaccinated.

    And then, globally, we have less than a quarter of people globally are even vaccinated. And there's some estimates that it will still take another year until we get enough people in other countries vaccinated. That's really a catastrophe for the world.

    It's a catastrophe for — many of these are individuals in the global South, massive inequities because we are not vaccinating. It is important that those countries like the U.S. that have substantial portions of their population vaccinated turn their attention to making sure that the rest of the world also is protected.

    It's an interest — it's in our interests.It is an essential interest for equity. But also we know that as long as the virus is being transmitted, variants, new variants develop. And so, ultimately, this is an our own self-interest as well, in addition to just our responsibility for the world's population.

  • William Brangham:

    All right, Dr. Kirsten Bibbins-Domingo from UCSF, always good to see you. Thank you very much.

  • Kirsten Bibbins-Domingo:

    Thank you.

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