Public Health

Heart failure, stroke & COVID: The latest research with Andrea Garcia, JD, MPH


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, medical education, advocacy issues, burnout, vaccines and more.

AMA's Vice President of Science, Medicine and Public Health, Andrea Garcia, JD, MPH, shares new data from the CDC detailing COVID-19 mortality rates for vaccinated and unvaccinated people, preliminary findings on coronavirus infection and heart complications from a small study at Columbia University in NYC, as well as the latest research on lasting heart problems related to COVID infection published in the Journal of the American College of Cardiology. American Medical Association Chief Experience Officer Todd Unger hosts.


  • 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: Good to be back with you this week.

Unger: Well, last week, we were off to attend the AMA's National Advocacy Conference in D.C. I hope you caught that amazing discussion with Todd Askew, our head of advocacy in D.C. It's almost enough time to make me forget about the subvariant XBB.1.5. Andrea, what's happening out there with that?

Garcia: Well, if we look at the CDC variant tracker, XBB.1.5 is now responsible for about 80% of COVID cases here in the U.S. There's no question that it continues to be the most dominant variant right now. And that continues to grow week over week. The last time we reported, about two weeks ago, it was responsible for about 64% of cases.

And so with that continued dominant of XBB.1.5, those same variants BQ.1.1 and BQ.1 have decreased. And now, they're representing only about 16% of new cases.

Unger: Well, with the move to that being the more dominant strain, are we seeing an impact on cases?

Garcia: Well, if we look at the New York Times data, reported cases are declining nationally, but the pace of that decrease is starting to slow in recent days. This has been driven by rising COVID cases in about half of all states. If we look at Western states, like Montana and Wyoming, cases there have increased about 55% in the past two weeks. But nationally, we're at about 36,000 cases, on average. Overall, that's a decrease of about 10% in the last two weeks.

Unger: And what about hospitalizations and deaths? How do those correspond?

Garcia: So on average, we're seeing about 28,800 people hospitalized with COVID daily. That's a decrease of about 5% over the last two weeks. And hospitalizations have increased in many parts of the West where cases are also increasing. But we're not seeing those same increases across the board. In other parts of the U.S., hospitalizations have leveled off.

If we look at the data for deaths, they remain persistently high. On average, around 3,000 people are still dying of COVID in the U.S. each week. We're still seeing daily averages that are hovering just under 400 deaths per day. I think the good news that is a decrease of about 17% compared to two weeks ago, but that number is still far too high.

Unger: It is really high. And one thing that I notice is not as high is just what we hear about, the need to get vaccinated. A lot of just the general chatter about that seems to be at a much lower level. Are we making progress in terms of getting people vaccinated?

Garcia: Well, not really. Only about 60 million Americans have received that updated bivalent booster dose. And while that sounds like a big number, it's only about 16% of the U.S. population. And with daily deaths still high despite cases decreasing, the CDC is urging everyone six months of age and older to get that bivalent booster if they haven't already.

There was a recent CDC report that revealed that bivalent booster recipients had higher protection against infection and significantly higher protection against death than those who receive the monovalent booster or were unvaccinated. And that's especially true among older adults. And of course, these findings are consistent with previous studies that found people who have not been vaccinated run much higher risk of dying from COVID-19 than those who've been vaccinated.

Unger: Andrea, tell us specifically, what do we seeing from those stats?

Garcia: So if you take a look at this graphic from the CDC, people who received the bivalent booster were 14 times less likely to die from COVID than people who were unvaccinated and three times less likely to die than those who only received the original monovalent COVID-19 vaccines.

All eligible people can and should get that bivalent booster dose two months after their COVID primary series or their last monovalent booster dose. And we know, for many people, it's been much longer than two months. And at this point, there's really no reason to wait. 

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Unger: Andrea, those are really amazing stats, 14 times less likely to die than being unvaccinated? Three times less likely than if you just receive the original shot but not the boosters? Really important. And now, there's even more reason to avoid COVID. We've got some evidence that it can also lead to heart complications. Tell us more about those findings.

Garcia: We've known for some time now that COVID can cause damage to the heart. But a new study is taking a look at some of the molecular level changes that are thought to be caused by the virus that can potentially lead to lasting problems, such as irregular heartbeats and heart failure.

I think it's important to note that this research is still preliminary. The findings were presented earlier this week at the biophysical society meeting in San Diego. But they haven't yet been published in a peer-reviewed journal.

Unger: Tell us a little bit more about how that particular study was conducted.

Garcia: So researchers from Columbia University examined autopsied heart tissue from people who had COVID. And they found that the infection can cause changes in the calcium channels that ultimately affect how the heart beats. And it can also trigger inflammation and oxidative stress in the heart.

To study the changes further, a mouse model with utilized, and the patterns observed were consistent with the changes observed in human hearts. The study was small, and the next step would be to conduct the research on a larger scale. But the message from researchers to physicians is that doctors should be aware of changes related to the heart due to COVID-19 infections and should be looking for those changes.

The researchers hope that this study leads to increased awareness and eventually treatments for those whose hearts have been damaged by COVID infections.

Unger: Andrea, can getting vaccinated help with that situation?

Garcia: Now, there's actually another new study that was published this week in the Journal of the American College of Cardiology. It suggests that vaccination may protect against major cardiovascular events, like heart attacks and strokes that are associated with COVID.

And that study analyzed data from nearly two million people in the National COVID Cohort Collaborative database. Around 218,000 people had received at least one dose of an mRNA vaccine or the J&J vaccine. And according to the research, even partial vaccination was associated with a risk of lower cardiovascular events for at least six months.

More research is going to be needed to confirm whether COVID vaccination reduces the risk of these cardiovascular events. But this provides good evidence and another good reason to get vaccinated.

Unger: Thanks, Andrea. Now, the last thing I think we all want to think about is yet another virus that's out there. But I did see something on social media. It said, wash your hands and hope you don't get this because we now have another pretty common contagious virus that seems to be on the uptick. What do we need to know?

Garcia: Well, you're probably talking about norovirus, which, as you mentioned, is highly contagious. Sometimes it's referred to as stomach flu, but it's not actually related to the influenza virus. And according to the CDC, norovirus is rising nationwide. It appears to be at a seasonal high. The average percent of norovirus tests coming back positive is at about 17%, which is higher than at any point it was in 2022. And here in the Midwest, we've really had the highest average of test positivity in the nation.

Unger: Good reason that I don't touch anything. What are the symptoms? I think we can guess that. And how do you treat norovirus?

Garcia: The virus typically comes with GI symptoms, like diarrhea, vomiting, nausea, stomach pain, mild fever. And aches and pains are also possible. Norovirus is a leading cause of foodborne illness in the U.S. It spreads easily through hands, surfaces, as well as through food and water.

And it's commonly spread through direct contact with an infected person, such as by caring for them or sharing food or eating utensils with them. And I think it's important to keep in mind that individuals with the virus can transmit it for days and even up to two weeks after they're feeling better. And it really only takes a few particles to make you sick with this virus.

So as you said, take those infection control precautions. There is no treatment for norovirus, but the CDC does recommend drinking lots of fluid to prevent dehydration. And the illness typically resolves within a few days. It's rare, but people can be hospitalized or die in some cases.

Unger: I'm washing my hands in my own mind right now. Now, let's talk yet about something else. Another headline that's cropped up is about bird flu. Now, I've been reading about that since wreaking havoc across the country, certainly, on the avian side. But what about humans? Is this something that we need to be worried about?

Garcia: Well, avian influenza or bird flu is really getting some renewed attention that the flu virus that is causing attention, it's type A. It's H5N1. It's a highly pathogenic avian flu. According to CDC, H5N1 viruses are well adapted to spreading efficiently among wild birds and poultry. And they've been detected among many regions of the world.

It was first identified in the U.S. in January of 2022. The U.S. continues to experience outbreaks in wild birds and poultry. And we've seen some sporadic infections in different mammals, including bears, foxes and skunks. And that's been true in Canada and the U.S.

Unger: How worried do we need to be?

Garcia: Well, the virus has been detected in wild birds in all 50 states and it's caused poultry outbreaks in 47 states. It's affected more than 58 million commercial and backyard poultry flocks. But to answer your question about how much we need to worry, the short answer is the CDC is saying the risk to the general public right now is low. The current outbreak in poultry and birds continues to mostly be an animal health issue.

These H5N1 bird flu viruses do not currently have that ability to bind easily to receptors in the upper respiratory tract of humans or to transmit among people. But we're watching this closely. As we know, viruses mutate. That could make it more easily transmitted among people in the future and potentially between people. And that's the real worry, as usual. We'll continue to keep an eye and provide any updates as needed.

Unger: Well, Andrea, if there's a virus out there, we know that you'll keep us updated. Thanks so much for being here with us today. And we'll be back with another episode soon. You can find all our videos and podcasts at Thanks for joining us today and please, take care.

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