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Over the past week, we’ve seen a domino effect in Europe with country after country hitting pause on the administration of AstraZeneca’s Covid-19 vaccine. The concern stems from a small number of cases of serious blood clotting, which have not been definitively linked to the vaccine and don’t appear to be more frequent than what’s seen in the general population.

On Thursday, the European Medicines Agency found the vaccine to be safe and effective and said that vaccinations can resume. But, there’s a risk that this whole stop-and-start vaccine rollout has done irreparable damage to public perception of AstraZeneca’s product, which, of course, could have serious repercussions for the effort to end the pandemic. To discuss this issue, STAT spoke with Alison Buttenheim, an associate professor of nursing and health policy at the University of Pennsylvania, whose research focuses on vaccine acceptance. Please note that this interview took place before European Medicines Agency cleared the vaccine.


Excerpts of the conversation are below, lightly edited for clarity.

Let’s start with the big picture. What was your immediate reaction when you saw major world powers like France and Germany suspending the use of AstraZeneca covid vaccine?

Well, first reaction was that’s really unfortunate because we’d like to get this vaccine out as quickly as possible to as many people as possible, and then right behind that reaction was, I really hope that an investigation can be rapid and can demonstrate the the continued safety of the vaccine.


So just last week, a few European leaders, including Italian Prime Minister Mario Draghi, were publicly defending the safety of the AstraZeneca vaccine. What kind of public health risks might be created by there being mixed messages in the minds of people of Europe?

This is really distressing to the public when one authority says, “this vaccine is safe, we stand behind the trial results.” And at the same time, public health authorities in a different country are saying, “we’re pausing rollouts.” And that happens because people are looking at different sets of data. The trial data looked very good. There’s been an excellent safety profile so far with this vaccine, and yet other other countries, other authorities are looking at events that have happened to people who just received the vaccine and making a different call. That’s been a source of of distress, and confusing on many fronts during the pandemic. The vaccine rollout won’t be any different.

So assuming that the European Medicines Agency recommends resuming the distribution of the AstraZeneca vaccine, what would your advice be for the countries who have to explain this whole saga? Like, how do you convince people that a vaccine is safe when you just implied that it might not be?

It’s really hard to go back on on a pause. And it does, unfortunately, speak to just general scientific literacy in the public. These are very challenging concepts to explain. But I think the core concepts that we hope we can get across when there’s a resumption of the vaccine are — what were these agencies looking for? Two things, biological plausibility — is there a mechanism by which this vaccine could have produced blood clots and low platelet counts? And were the rates that we saw in the people who received the vaccine different from background rates or baseline rates? I’ve already lost like three quarters of the public, just in that one sentence. But those are the those are the scientific concepts we need to get across.  It’s just going to have to be consistent and repeated. It would also be great if some high-profile folks said, “I’m sorry, I’m getting the AstraZeneca vaccine tomorrow. I looked at the data. I’m very confident about it. I’m getting it. My mom’s getting it. My kid’s getting it.” That’s I think that kind of endorsement will be helpful as well.

So before any of this saga really began, the evidence supporting the AstraZeneca vaccine was maybe a little more complicated than the data we saw on other Covid-19 vaccines. There were variances in dosing and the results presented had been pooled from a handful of different clinical trials. I was curious, do you think that might have planted the seeds of doubt before these sort of clotting safety fears really came to bear?

A year ago, I would have said absolutely not, but everyone’s a whole lot more expert in vaccine trials than than they were a year ago. And people care about those things. We now have these different characters in a story. Each vaccine sort of takes on a different character. And people do associate both efficacy results and how the trials were done.

So this question is maybe a little premature, since we’re still in the thick of this, but do you see a lesson to be taken from this situation in terms of public health, in terms of vaccine acceptance and how we might manage situations like this, as they quite likely may continue to happen with more and more vaccines coming to bear and more people don’t have we learned something about how to communicate risk without unnecessarily sowing fear?

I think the solution was actually embedded in your question. We have to prepare the public for the fact that this is going to happen. And there was a little bit of that when the first two vaccines were submitted for emergency use authorization in the U.S. But if you’re going to vaccinate millions of people, bad things are going to happen to those people after they get the vaccine, and we have ways to figure out if that’s associated with the vaccine or not. And we will follow those safety protocols and procedures — that just has to be hammered home again and again and again. The stories, the anecdotes, are always going to be more memorable for people. The physician in Florida who died, these cases in in Norway, and we have a harder story to tell about numbers and ratios and protocols and biological plausibility. So we have to get it right and prepare people.

In your personal life or your professional life, have you come across people that, maybe, are vaccine hesitant or anti-vaccine? And how how have you how have you dealt with that?

So I’m a vaccine acceptance researcher, have studied this for 10 years, and I think most of my friends and family don’t tell me when their vaccine hesitant because they know they’re going to get the spiel. And I will say with this vaccine, it also feels different.

Mostly I study parents and their decisions about vaccinating their kids. And I’m actually quite impatient with refusal or hesitancy. With this vaccine, I think we have to come with a little bit more humility and and curiosity and respect about where people are with their decision. Historical distrust, structural racism in health, the fact that this vaccine, these vaccines were produced faster than vaccines have been in the past. So when I encounter people saying, “I’m going to wait,” or I have preferences for one vaccine over the other, I’m really trying to be patient.

 Yes, I would love it if everyone got vaccinated. The goal should be that 100% of people were reached with the information and support they needed to make the decision that was right for them. That’s very hard for me to admit that that’s how I feel, but that’s actually how I feel. We need to recognize that different people are going to need different kinds of information support.

  • The Big Elephant in the room wasn’t mentioned — these vaccines are authorized under emergency situations, but they haven’t been approved by the FDA. How do you explain what this means in terms of safety and potential long-term effects?

  • I am no genius.
    But using some deductive reasoning..

    “The Medicines and Healthcare Products Regulatory Agency in Britain said the benefits of the AstraZeneca vaccine continue to outweigh the risks because of the “extremely rare rate of occurrence” of the blood clots and because a link to the vaccine is unproven.”

    AstraZeneca COVID-19 vaccine ingredients
    One dose (0.5 ml) contains: COVID-19 Vaccine (ChAdOx1-S* recombinant) 5 × 10^10 viral particles (vp)
    L-Histidine hydrochloride monohydrate
    Magnesium chloride hexahydrate
    >>Polysorbate 80<<
    Sodium chloride
    Disodium edetate dihydrate
    Water for injections

    "Clinical studies have shown darbepoetin alfa (polysorbate 80) to increase the risk of serious side effects (eg, blood clots, stroke, heart attack, heart failure) and death in some cases."

    It may be necessary for AstraZeneca to replace the "Polysorbate 80" with an alternative that has not been shown to cause to blood clots, how ever rare it may be.

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