Public Health

New study on colon cancer bacteria, recent measles outbreak, MMR vaccine dose and U.S. life expectancy [Podcast]


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AMA Update

New study on colon cancer bacteria, recent measles outbreak, MMR vaccine dose and US life expectancy

Mar 25, 2024

Measles outbreak 2024: Why is measles on the rise? Can bacteria in dental plaque cause colon cancer? CDC measles update, new leading causes of death and colon cancer.

Our guest is AMA's Vice President of Science, Medicine and Public Health, Andrea Garcia, JD, MPH. American Medical Association CXO 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. I'm Todd Unger, AMA's chief experience officer. Welcome back, Andrea.

Garcia: Thanks, Todd. It's great to be here.

Unger: Well, last week we began with the measles outbreak here in Chicago and across the country. Anything changed in the last week?

Garcia: It has. Actually, here in Chicago we are up to 15 reported cases of measles. Of those additional three cases that have been reported since the last time we talked, the Chicago Department of Public Health has indicated that two of those cases were in children who are four years old or younger. Overall, cases are still rising both here in the U.S. and globally. And in response, we saw the CDC issue a health alert, or a HAN, last Monday.

And that was really urging families, schools, physicians and others to work together to ensure that children receive all recommended doses of the MMR vaccine. And then that alert also encouraged all U.S. residents who are six months and older who are traveling internationally to be current on their MMR vaccinations. And just as a reminder, children who are not traveling internationally should receive that first dose of the MMR vaccine between the ages of 12 and 15 months, and then their second dose between four to six years of age.

However, as we discussed last week, the CDC has issued that separate guidance for those who are traveling internationally. So all U.S. residents older than six months without evidence of immunity who are planning to travel internationally should receive the MMR vaccine prior to their departure. In other words, you may see some babies getting that first dose a few months ahead of the routine immunization schedule, and then these infants should receive two more doses of the MMR vaccine. The first would be administered when they are 12 to 15 months, and the second at least 28 days later. Children who are 12 months and older, teenagers, adults without evidence of immunity who are traveling internationally, should also receive two doses separated by at least 28 days. So that's a tighter window between those vaccinations.

Unger: All right, well thank you for that guidance, Andrea. Did the alert itself share any other details or provide additional context on the outbreaks?

Garcia: It did. And according to that alert, as of March 14, the CDC had recorded 58 cases across 17 states. That's the same number of cases we saw in all of 2023. And with those numbers being reported weekly, it's likely that number is higher by now.

Most cases reported this year have been among children aged 12 months and older who have not received the MMR vaccine, and 93% of the cases have been linked so far to international travel. And as we talked about last week, so many of the countries experiencing outbreaks globally are popular tourist destinations―Austria, the Philippines, Romania and the U.K.

Unger: Well, many physicians may have never treated measles. What should physicians do if they suspect a case of measles in a patient?

Garcia: Yeah, I think what makes measles tricky is that people are contagious before they even realize they have it. And as we've discussed several times before, it's extremely contagious. And that's why if you look at the CDC recommendations, you'll see they suggest in a health care setting, isolating suspected patients immediately.

Patients with suspected measles should not remain in waiting rooms or other common areas of a health care facility. Ideally, they're being placed in a single-patient airborne infection isolation room, if available, or in a private room with a closed door until an AIIR is available.

Physicians should also immediately notify state, tribal, local or territorial health departments about any suspected cases. And that's to ensure rapid testing and investigations. States then report those measles cases to the CDC.

I think physicians also should be really vigilant in contact with their state and local health department for guidance on testing given the possibility of shortages of IgM test kits.

And then, in coordination with local or state health departments, appropriate measles post-exposure prophylaxis should be given as soon as possible after that exposure to close contacts in people without evidence of immunity to help prevent spread.

Unger: Now, Andrea, I think many of us think of measles as kind of that telltale rash. But there are other symptoms to watch for. Can you give us more background on that?

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Garcia: Yeah, typically it takes anywhere from one to two weeks for someone to start feeling ill after coming into contact with the virus. And then, even then, those earliest symptoms are not usually the rash. They tend to be a cough, runny nose, pink eye and a high fever. And in fact, some people may have a fever that goes above 104 degrees, which we know can be dangerous in some populations. According to the CDC, fewer than one in every 10 people with measles will also develop diarrhea.

From two to three days after those symptoms first appear, people may develop tiny white spots on the inside of their mouth. And then a day or two later, the rash develops. According to the WHO, that rash usually fades around six days.

We know measles can lead to serious complications and even be fatal, so it's really important to be proactive and to get vaccinated if you're not protected. CDC is currently working with state and local health departments to try and identify those pockets of low vaccination and to prepare those areas for potential outbreaks.

Unger: All right, well thank you so much for that update on measles. We'll certainly continue to follow that and hopefully begin to see some of those numbers coming down soon.

In more news from the CDC, the agency has launched a new resource. Andrea, tell us more about that.

Garcia: Yeah, it's actually a new monthly newsletter called the CDC Chief Medical Officer's and MMWR Clinical Pearls. As you know, the CDC chief medical officer is Dr. Debra Houry, who you've had on AMA Update before. This newsletter is being put out by her, and it provides brief summaries of recent MMWR reports and recommendations that are particularly relevant to clinical practice. It's a great way to get the highlights from the past month all in one place. Especially, we know busy physicians may not have that time to read through the more detailed MMWR. So we'll provide links in the description of this episode where physicians can go to get more information about that new newsletter and subscribe.

Unger: Excellent, that sounds great. And following up now on something else that we recently discussed―colon cancer. Last week we talked about how there could soon be a blood test that can help detect colon cancer. This week, we have more developments. Andrea, what do we need to know there?

Garcia: Yeah, so there was a study published last Wednesday in the journal Nature, and it found a new type of bacteria that was present in about 50% of colon cancers. And many were aggressive cases. We saw NBC News cover that study and report that the bacteria found is the same bacteria that causes dental plaque. It's usually only found in the mouth, where it's one of the most common types of disease-causing bacteria. It's linked to gum disease and plaque buildup. And I think while scientists have long suspected that there may be a link between the bacteria and colon cancer growth, it was really unclear how it could withstand the journey through to the gut.

And the study revealed that bacteria was a bit more complicated than they initially thought. It has two distinct subtypes, one which appears to shield colorectal tumors from cancer-fighting drugs. So it acts like a cloak and could be behind a certain treatment-resistant form of colon cancer.

According to researchers, patients who have high levels of this bacteria in their colorectal tumors have a far worse prognosis, and the subspecies may also cause cancer to form in the first place.

Unger: Wow, so much still to learn, and so many connections to be made. Andrea, what does this mean exactly?

Garcia: Well, experts say that the discovery could pave the way for new treatments, possibly as well as new methods of screening. For example, one physician said that there's evidence that if you clear these bacteria, there is more response during treatment. There will also be soon clinical trials to test whether treating a patient with antibiotics prior to chemotherapy will induce a better response.

It's also possible that scientists could identify the subspecies while it's still in the mouth and give a person antibiotics at that point, wiping it out before it can travel to the colon, or at the very least indicate that a person is at higher risk for aggressive colon cancer. So there's a lot to be hopeful for with this discovery.

Unger: Absolutely. And on another positive note, we recently learned that U.S. life expectancy rebounded a bit. Tell us more about the numbers there.

Garcia: Yeah, so there were two new studies released this past Thursday by the CDC. Life expectancy in the U.S. bounced back in 2022. It increased by about one year, from 76.4 years in 2021 to 77.5 years on average. Unfortunately, it wasn't all good news. Even though we saw that improvement, life expectancy remains below that peak of 78.9 years, which we reached in 2014. The U.S. life expectancy also lags behind other comparable countries, and we unfortunately saw the mortality rates among infants and children increase.

That final data that was compiled by the CDC shows two public health crises, the COVID pandemic and the overdose epidemic. And those are still causing far too many deaths. So COVID took roughly 186,000 lives in the U.S. in 2022, and we saw almost 108,000 fatal overdoses in 2022, largely driven by fentanyl.

The leading causes of death in the U.S. are heart disease and cancer. We did see unintentional injuries overtake COVID-19 as the third-leading cause of death. COVID-19 dropped to the fourth-leading cause of death in 2022. Researchers say that more recent provisional data is showing that trend really continuing, with those pandemic-related deaths on the decline and drug overdoses increasing in 2023 to over 110,000 fatalities.

Unger: That's a pretty distressing stat. And I know the AMA is working to reduce those numbers through its Substance Use and Pain Care Task Force. And that work is going to continue to be so important.

Andrea, that wraps up today's episode. I want to thank you for being here and keeping us all informed. For those of you who are listening out there, if you found this discussion valuable and you want more trusted public health information, please support the AMA by becoming a member at

We'll be back soon with another AMA Update. In the meantime, you can find all our videos and podcasts at Thanks for joining us. 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.

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