Public Health

XBB.1.5, new COVID-19 and flu at-home test, plus CDC shigellosis warning with Andrea Garcia, JD, MPH [Podcast]


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AMA Update

XBB.1.5, new COIVD-19 and flu at-home test, plus CDC shigellosis warning with Andrea Garcia, JD, MPH

Mar 1, 2023

Is it COVID or flu? XBB.1.5 variant still dominates, but FDA has authorized Lucira Health's new at-home COVID test that also identifies influenza A. In today’s AMA Update, AMA's Vice President of Science, Medicine and Public Health Andrea Garcia, JD, MPH, discusses the latest coronavirus trends, seasonal influenza activity, plus CDC's recent health alert for shigellosis infections caused by the XDR Shigella bacteria strain. AMA 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. Hello, Andrea.

Garcia: Hi, how are you?

Unger: I'm great and let's talk COVID cases. First off, last week, we were talking about a trend that showed them declining. Same story this week?

Garcia: Yeah, if we look at The New York Times data, overall, cases are down nationally. We are seeing some states. We look at Nebraska and Utah, where cases have been rising since the middle of February, but nationally, there's about 34,000 new cases being reported every day on average. That's a decrease of about 14% over the last two weeks.

And then, if we look at the CDC variant data, XBB.1.5 continues to grow and is the dominant variant in the U.S. That's now about representing 85% of COVID cases. And BQ.1 and BQ.1.1 continue to decrease, and they're accounting for about 12% of new cases.

Unger: Andrea, how are those numbers translating into hospitalizations and deaths?

Garcia: So hospitalizations are still increasing in some of the western states, but nationally, we are trending downward. On average, there are about 28,000 people hospitalized for COVID daily. That's about a 5% decrease over the last two weeks and then deaths are finally starting to decrease.

On average, we're seeing around 330 people dying of COVID each day. That's a 26% decrease from two weeks ago. So it's good to see those numbers finally start to come down a little bit.

Unger: Absolutely. And that has been a number that has just been in place for a long time, so it is excellent to see that decline. Andrea, we also heard this week about a new at-home test that was recently authorized by the FDA. Tell us more about that and why it could be a gamechanger.

Garcia: Well, so during the COVID pandemic, people really got used to taking at-home tests for COVID 19. And now, the FDA has authorized what it says is the first at-home test that can tell people if they have the flu and/or COVID. The test was made by a California biotech company, Lucira Health.

It uses a single self-collected nasal swab and it can provide results in about a half an hour. And like the COVID test, it could test for COVID and flu—is available without a prescription. It's currently authorized for anyone 14 and older for self-collection or adults can use it for children two years of age and older.

Unger: Now, we know, Andrea, that people are now used to being able to give themselves COVID tests, but in the early days, there were questions about accuracy. That was always kind of an issue. Do we have any sense of how accurate this new test is?

Garcia: Well, if you look at the data from the manufacturer, the test is able to identify a negative result for influenza A with 99% accuracy and a positive result with more than 90% accuracy. It's 100% accurate for negative COVID samples and more than 88% accurate for positive results. There wasn't enough influenza B circulating while the testing was being done, so we don't have data to measure that performance.

The company says that they'll have to do a real-world test when there is enough virus in circulation. But in lab studies, it caught nearly 100% of negative cases. Of course, the FDA said that all tests carry a risk of a false positive or a false negative.

Unger: So if people do test negative, is the advice to test again in a couple of days, similar to kind of how we think about at-home COVID tests?

Garcia: Well, negative results should be confirmed with a lab test, if it's necessary for patient management. People who test positive for flu or COVID should take precautions, of course, so they don't spread the illness to others. People who have flu or COVID-like symptoms but test negative could have another kind of respiratory infection and could qualify for followup care. The FDA did say that the collective impact of COVID, flu and RSV really underscores that importance of diagnostic tests for respiratory viruses and recognizes the benefits that at-home testing can provide.

Unger: It's nice to have another kind of tool in the armament, so to speak. And speaking of flu, we haven't really talked about flu numbers in a while. Andrea, tell us where we stand. And are we still kind of in the height of flu season?

Garcia: Not really. If we look at the recent Flu View Report, seasonal influenza activity is low, nationally, which is good news. And that proportion of laboratory specimens testing positive for flu at clinical labs nationally has declined for the 10th consecutive week, so that's a good trend.

And systems that track flu hospitalizations also continue to show declines and have been declining for weeks now. Levels are similar to what we usually would see in late spring. Overall, key indicators suggest that this has been a moderately severe flu season, but of course, that classification could change before the season is over.

Unger: It makes me really glad that my family and I both—we all got our flu shots. But for those who haven't gotten one, is it too late in the season to get a flu shot, or is that still the recommendation?

Garcia: It's not too late yet. The CDC continues to recommend getting that annual flu vaccine as long as flu viruses continue to spread in the community. I mean, tragically, we did see 115 pediatric flu deaths reported in the U.S. so far this season. Everyone six months and older, with rare exceptions, should get that flu vaccine every season.

This season, we have seen some concerning drops in flu vaccine uptake in certain groups. You can find a flu vaccine by visiting and entering your zip code. And of course, if you have questions about flu vaccines, you can visit for more information.

Unger: Those are some tragic figures—and again, just underscoring the importance of getting that flu vaccine. Andrea, too, I know the annual flu vaccine can be a bit of a guessing game, in terms of which strands are going to be dominant each season. How have we done this season in predicting that?

Garcia: The early data suggest the flu vaccine has performed well, and that is most likely due to the fact that the vaccine does appear to have been a good match against those strains that were spreading through the fall and winter. During the CDC vaccine meeting last week, health officials said that data indicates the vaccines were more than 40% effective in preventing adults from getting sick enough from the flu that they had to go to a doctor's office, clinic or hospital. And generally, it's good news if that flu vaccine is about 40% to 60% effective.

Unger: So Andrea, we were, just a couple of months ago, talking about the triple-demic of RSV, flu and COVID. I was riding up the elevator the other day and I saw yet another thing to worry about, so let's talk about it—a new bacteria that's getting some attention, warning and CDC alert. Tell us more about that.

Garcia: The CDC issued a health advisory to warn the public of an increase in shigellosis infection caused by XDR Shigella bacteria strain. It's a drug-resistant strain. It can cause fever, abdominal cramping and diarrhea.

It can be transmitted through the fecal-oral route, directly from person-to-person contact, including sexual contact and indirectly through contaminated food and water. Historically, this has impacted young children from age 1 to 4, but the CDC is starting to see more of the antimicrobial-resistant infections in adult populations, especially men who have sex with men, people experiencing homelessness, international travelers and people living with HIV.

Unger: Oh, boy. What do physicians need to know about this?

Garcia: Well, patients may recover from shigellosis without antimicrobial treatment. Oral rehydration may be sufficient for people with an infection and health care providers treating those with the drug-resistant infection should consult with a specialist knowledgeable in treating antibiotic-resistant bacteria to determine the best treatment options.

We know that overusing antibiotics can contribute to the development of antimicrobial resistance. And of course, we and CDC recommend using antibiotics only when clinically indicated. And finally, we should note that this is a nationally-notifiable disease, so health care professionals should be reporting all cases to their state and local health departments.

Unger: Well, thank you so much, Andrea. We'll be keeping an eye on that story, and we'll keep you updated as things progress. That wraps up today's episode. Thanks for being here today and please check out all our 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.