Public Health

Vaccine stroke risk, new MIS-C data & pediatric vaccine decline with Andrea Garcia, JD, MPH [Podcast]


AMA Update covers a range of health care topics affecting the lives of physicians, residents, medical students and patients. From private practice and health system leaders to scientists and public health officials, hear from the experts in medicine on COVID-19, monkeypox, medical education, advocacy issues, burnout, vaccines and more.

AMA Update

Vaccine stroke risk, new MIS-C data & pediatric vaccine decline with Andrea Garcia, JD, MPH

Jan 18, 2023

In today’s AMA Update, AMA Vice President of Science, Medicine and Public Health Andrea Garcia, JD, MPH, discusses recent release by CDC, FDA regarding possible link between Pfizer's bivalent booster and stroke risk for those 65 and older. Also covering the potential increased risk of measles, mumps and rubella for kindergartners given a decrease in pediatric vaccinations this year, as well as new findings regarding multisystem inflammatory syndrome (MIS-C) in children. AMA Chief Experience Officer Todd Unger hosts.

Learn more at the AMA COVID-19 resource center.


  • Andrea Garcia, JD, MPH, vice president, science, medicine & public health, American Medical Association

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Unger: Hello and welcome to the AMA Update video and podcast. Today, we have our weekly look at the headlines with the AMA's Vice President of Science, Medicine and Public Health, Andrea Garcia, in Chicago.

I'm Todd Unger, AMA's chief experience officer, also in Chicago. Welcome back, Andrea.

Garcia: Thanks. It's good to be here.

Unger: Well, let's start off by talking about this sub-variant XBB.1.5, which is responsible for more and more of the COVID cases here in the U.S. Andrea, what's the latest data telling us about this?

Garcia: Well, last week CDC showed that XBB.1.5 was the second most dominant strain here in the U.S. and it was accounting for about 28% of cases. But as of this Friday, CDC is reporting that XBB.1.5 is now the most dominant strain and it accounts for about 43% of COVID cases. BQ.1.1 was the most dominant strain before last week. And that's now dropped to the second most dominant strain. And it's responsible for about 29% of cases here in the U.S.

Unger: Well, there's been a lot of talk about the transmissibility of this particular variant. Is that affecting our case counts?

Garcia: Well, after double-digit percentage increases in that daily average number of new cases last week, that number of new cases does finally seem to be slowing down. And if we look at the New York Times data, that daily average of new cases is around 60,100. That's an increase of about 4% from two weeks prior.

We're also seeing test positivity at about 13%, which is lower than last week, but still pretty high.

Unger: And how is that translating into hospitalizations and deaths?

Garcia: So last week we talked about the fact that we were seeing double-digit percentage increases in both hospitalizations and deaths. I think the good news is that daily average of hospitalizations is around 44,000, which is a slight decrease of about 2% from two weeks prior. But the average number of daily deaths continues to increase.

And this past week, that number was around 560 deaths. And that represents a 78% increase from two weeks ago. According to the New York Times, deaths certainly are rising. But part of this increase could be due to interruptions in reporting due to the holidays. And so we could be seeing inflation in that number. So we'll need to keep a close eye on those numbers to see if they level out in the coming weeks.

Unger: Well, let's turn our attention to the COVID vaccine. And there's been some news from the CDC regarding Pfizer's bivalent vaccine. And we're going to take an in-depth look at that with an update from AMA board chair Dr. Sandra Fryhofer, who is the AMA's ACIP liaison, later in the week.

But Andrea, at a high level, what do we need to know about this?

Garcia: So on Friday afternoon, the CDC released a statement and noted that they had identified a preliminary safety signal with the bivalent COVID vaccine made by Pfizer. They noted in this statement that it's unlikely to represent a true clinical risk. They had said that one of their vaccine monitoring systems, which is the vaccine safety data link, detected this possible increase in ischemic stroke in people 65 and older who had received that Pfizer bivalent dose.

Analysis of that safety signal revealed that seniors who got that bivalent booster might be more likely to have that stroke within the first three weeks after receiving their shot compared to weeks four through six. That same safety signal has not been detected with Moderna's bivalent booster dose, according to CDC release.

Unger: So it seems like we have more to learn there. At this point, do we need to be concerned?

Garcia: Well, neither Pfizer nor other countries that are using the vaccine have seen that increase in ischemic strokes. And the agency indicated that signal was not detected in other databases. That they looked at CMS data. They looked at data from the VA, data from VAERS.

They haven't seen it in other systems. They are not currently recommending any change in the clinical vaccine recommendations at this time. And I would just remind people that risk for COVID for older adults continues to at this point outweigh any possible safety issues with the vaccine. The CDC also stated that although the totality of the data currently suggests that it's very unlikely that the safety signal in their vaccine safety data link represents that true clinical risk, they believe it's important to share this information with the public, as they've done in the past when a safety monitoring system detects the signal.

So we're seeing transparency here from the federal agencies sharing what they know so far. Of course, CDC and FDA are going to continue to evaluate additional data from their other vaccine safety systems. We do expect them to provide an update at the FDA'S Advisory Committee meeting next week. And of course, you'll hear more details from Dr. Fryhofer very soon.

Unger: Indeed. Well, thinking more broadly about vaccinations, there's also been some disappointing news regarding childhood vaccination rates from the CDC in general. So let's talk a little bit about what the latest here is?

Garcia: So last week, the CDC reported that the average percentage of kindergartners who have not received a routine child vaccination rose during the 2021-2022 school year. Overall, vaccination rates among kindergartners remain high. But that coverage has dropped about two percentage points from 95% pre-pandemic—so, think 2019-2020 school year—to 93% in 2021-2022.

In an article published in The Hill, the CDC said that while this might not sound like a significant decrease, it means that nearly 250,000 kindergartners are potentially not protected against measles alone. We know that coverage from measles, mumps and rubella during the 2020-2021 and 2021-2022 school years was the lowest that it had been in a decade. And these declines were also present in other routine childhood vaccinations.

So think about diphtheria, tetanus, pertussis, polio, chickenpox.

Unger: So kind of beyond that, the numbers themselves, which that's significant when you think about the big picture here, what's this mean?

Garcia: So if we have pockets of under-vaccinated children within larger areas where there is high vaccination coverage, we can see outbreaks, such as the cases we've seen in polio in New York and the recent measles outbreak that sickened more than 80 kids in Ohio. Some of this decline we know is due to the pandemic, which disrupted health care and efforts to get vaccinated. But certainly, vaccine hesitancy continues to be a problem as well.

CDC is asking people to talk to their physicians and calling on physicians to really initiate these conversations with patients where they can. We know that physicians and health care professionals remain a trusted voice and are an important way to have an impact on these numbers.

Unger: Andrea, there's also new research on MIS-C in children. Something we haven't really heard about in a while. What did the research find?

Garcia: The research suggests that cases of MIS-C post-COVID may be more common and more severe than previously reported. And just as a reminder, multisystem inflammatory syndrome in children, or MIS-C, is a rare condition.

It can occur two to six weeks after a child is infected with SARS-CoV-2. And MIS-C causes different internal and external body parts to become inflamed. So the heart, the lungs, kidney, the brain, skin, eyes or the GI tract. MIS-C can be serious. It can even be deadly.

But most children who are diagnosed with the condition get better with medical care.

Unger: Now, you mentioned the situation might have been worse than we were expecting. What does the data say?

Garcia: So an examination of billing code data for this rare condition turned up 4,107 hospitalizations for MIS-C in 2021. So that's about 17 cases for every 100 COVID hospitalizations among kids. Deaths occurred in 0.8% of the cases. And that number increased to 5.8% when six or more organs were involved.

Since the start of the pandemic, the CDC has received over 9,000 reports of this rare condition, which is still not well understood. The CDC is still learning the underlying reason why some children get MIS-C after SARS-CoV-2 infection and others do not. But we know the best way to prevent MIS-C is to protect against getting COVID in the first place. So that involves the usual precautions.

But also staying up to date with vaccines and booster doses.

Unger: Well, as much as it seems like we're kind of moving beyond at least the acute phase of the pandemic, the Biden administration just extended the COVID-19 public health emergency again. What's that mean, Andrea?

Garcia: Yeah, so last week we saw HHS Secretary Becerra renew that declaration on its expiration date. It's something that's been done every 90 days since that public health emergency was first issued in January of 2020. And that designation really gives the administration certain authorities and regulatory flexibilities to respond to the pandemic.

Unger: So again, some people think this is behind us. So what's driving a renewal of the public health emergency?

Garcia: So we heard Dr. Ashish Jha, who's the White House COVID response coordinator, say that this renewal was because there's still a lot of COVID out there and this public health emergency gives us the tools to fight this. Dr. Jha also said the highly contagious XBB.1.5 variant was just one of the reasons that prompted the decision. But it wasn't the only reason.

The public health emergency gives that federal government wide-ranging authority over a number of COVID-related areas. So if we think about data tracking and helping to ensure access to the vaccines and treatments. Another reason that's been stated is that we need more time for the transmission of vaccines and therapeutics into the private health insurance coverage.

Unger: That makes a lot of sense. Andrea, thanks so much for being with us here today. We'll be back next week with another update on the headlines. In the meantime, you can catch all of our AMA Update videos and podcasts at Thanks for joining us today. Please take care.

Disclaimer: The viewpoints expressed in this podcast are those of the participants and/or do not necessarily reflect the views and policies of the AMA.