A 17-Fold Increase in Measles Cases Puts Elimination Status at Risk in United States

In 2000, measles was effectively eradicated in the United States, meaning that there were no outbreaks for a year or more. However, the recent rise in measles cases in 2024 is threatening its elimination status in the United States, according to the CDC. In fact, the United States has seen more cases of measles as of April 2024 than all of 2023. Jennifer Walsh, DNP, CPNP, CNE talks with Consultant360 about the reasons for the sudden surge, what clinicians can do to make their patients aware of the increase, and the potential impact of losing measles elimination status in the United States.

Additional Resource: Mathis AD, Raines K, Masters NB, et al. Measles — United States, January 1, 2020–March 28, 2024. MMWR Morb Mortal Wkly Rep. 2024;73:295–300. DOI: http://dx.doi.org/10.15585/mmwr.mm7314a1

Consultant360: Can you please review the harms caused by the measles, particularly for young children?

Jennifer Walsh, DNP, CPNP, CNE: Yes, definitely. Measles can be a very dangerous disease, particularly for young children, as well as those who are immunocompromised. Most individuals who acquire measles are those young children or those who are immunocompromised or unvaccinated.

Children have a high risk of hospitalization and risk of death from measles. When we think about sequela from measles, we think about pneumonia, encephalitis, brain damage, deafness, and even death. Those are the most significant complications that we worry about.

C360: And the CDC found a sharp rise in measles cases in 2024. In fact, the number of cases, as of April of 2024, have already surpassed 2023. How does one account for that increase?

Dr Walsh: We've seen a 17-fold increase in 2024, which is pretty much more cases than we've had in the past several years combined. So, it's very concerning. In 2000, we effectively eradicated measles in the United States. There were no outbreaks. But we've seen that gradually increase over the past several years. There are multiple factors that we think play into this. We're a very international country. We have a lot of people coming and going, so we can't just think of the United States, but we should think globally as well. And worldwide, we've seen decreasing numbers of children being vaccinated in general, but particularly for measles. And we believe this really stems from a false study that linked autism to the measles vaccine back in the 1990s. This has since been debunked by multiple research studies. But the false theory that the measles vaccine can cause harm to children is still out there on social media, and various public figures continue to push that false information. We’ve worked hard with parents to try to reassure them that this information was false and to give them real evidence-based information to help make the best decision for their child.

We've also seen increasing vaccine hesitancy in the US since the COVID-19 pandemic, and ultimately, we're seeing a decrease in individuals who are vaccinated, particularly for measles. Typically, we like to see the vaccination rate as close to a 100% as we can get. When we get it above 95%, we can start talking about herd immunity, which really protects everyone, especially those who are unable to be vaccinated or those who are immunocompromised. We've seen that dip down to about 92% to 93% of kindergarteners being fully vaccinated. So that really puts millions of children worldwide at risk for measles and can really impact eradicating the measles.

C360: The CDC recently recommended that clinicians encourage parents to move up their infants’ vaccination a few months ahead of their typical schedule. Is that a big ask or a small change that could potentially make a difference down the line?

Dr Walsh: Well, I don't think it's a big ask. Typically, we start to give the measles vaccine on or after the patient’s first birthday, and then the booster comes at kindergarten age, at about 4 to 6 years of age. The first vaccine is usually about 93% effective, with that second vaccine bringing it closer to 97%, which pushes you above that herd immunity level target that we're trying to reach.

And measles is highly contagious. If you're in a room of 100 people who are unvaccinated against measles, and one person has measles, 90 people will get measles. It's that contagious. It’s not just from direct contact with an individual with measles either. The virus can last for up to 2 hours in the room after the individual leaves.

Regarding giving that vaccination earlier, as I mentioned, typically, we start on or after the first birthday, but it can be given as early as 6 months, so that can really protect against a fragile time for unimmunized children. And it's very, very safe. The only thing that it would require is to get two additional vaccines. Generally, after two vaccinations, you're immunized against measles, and we believe it's lifelong immunity. But if you were to receive an earlier vaccine before your first birthday, you would just need to get two others, so it would just add one vaccination in your lifetime. So, it's not a big ask. However, it can be a big ask in this environment when there's a lot of vaccine hesitancy.

C360: What other steps can clinicians take to help inform parents about slowing down this trend?

Dr Walsh: I recommend just continuing to point parents in the right direction for real evidence-based literature. Really talk about the risk-benefit of the vaccine. Discuss how we had it eradicated in the year 2000 and the reasons why we see that slipping back. So, I think educating our families, leading them to evidence-based resources, and speaking out about the efficacy of the measles vaccine would be my recommendation.

C360: How does the potential loss of elimination status for measles in the United States impact clinicians?

Dr Walsh: When we had it eradicated, it wasn't on our radar as much. Obviously, if a child had traveled from outside the country, then that would bring it to our attention. So that's a question that we always ask. But knowing that we're seeing outbreaks occur in the United States just heightens our differential diagnosis and makes us much more concerned. Measles can look like many other common viruses of children. But knowing that it could be measles increases our concern. We think about having children sit in the waiting room before being seen. We think about infection control. It’s really a virus that we don't necessarily need to think about when we've got that eradication status. But when we don't, it's on our radar.

C360: Is there anything else you would want our audience to know about this.

Dr Walsh: Thanks for asking, I would say vaccinate your children. If you're still hesitant about the risk and benefits of measles, go to your primary pediatric provider, seek evidence-based information, and talk with them. They are happy to have that conversation.

We know that we've got a tool that can eradicate measles worldwide, so it's frustrating, seeing it come back into our daily practice, come back into the news, and seeing the hospitalizations and deaths that are unnecessary. We have a very safe vaccine that works. I would say vaccinate.