Expert Doctors: Measles Has Now Been Identified in 6 US States

Updated: Feb. 22, 2024

Global public health authorities point to one major cause for the clusters of the virus, which was previously eradicated in the US but caused more than 300,000 infections in 2023.

While you’ve heard of measles and most likely have been vaccinated against it, you’ve probably never heard of anyone with the virus. That’s thanks to decades of a national protocol for the administration of an efficacious vaccine, which led to the 2000 declaration that measles had been eradicated in the US.

The measles vaccine is included in the MMR vaccine—which stands for measles, mumps, and rubella—of which nearly every American child receives two doses before kindergarten. Recently, however, measles has turned up again as several communities across the country have reported cases in Pennsylvania, Washington, New Jersey, Virginia, Georgia, and as CBS News reported on February 18, 2024, Florida.

On February 20, the World Health Organization said incidence of measles rose 79% from 2022 to 2023, with 306,000 cases reported last year. Meanwhile, data suggest that 130,000 individuals died from measles in 2022.

Here’s why measles is suddenly present

Expert doctors have stated to media outlets that in the cases above, there are two paths by which individuals generally contract measles. One is through travel to another country where there is a prevalence of cases. The second is through a domestic rise the virus caused by pockets of people who have not received the vaccine.

It’s reported the latter has increased in recent years due largely to vaccination hesitancy. While vaccine hesitancy existed before COVID-19, some parents are declining to get their children vaccinated according to the Centers for Disease Control and Prevention (CDC).

Further, outlets have reported that vaccinations for some children simply fell behind around the time of the pandemic due to more restricted access to preventive healthcare.

Measles returns when herd immunity in a community falls below 95%, which effectively keeps the illness at bay. This percentage is extremely important. In the Pennsylvania outbreak, the immunity percentage dropped below 93% in 2022.

Peter Hotez, MD, co-director of the Texas Children’s Hospital Center for Vaccine Development called the rise in measles cases “a wake-up call” in an interview with CBS News, adding: “The real number in many communities is probably far below 93%.”

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Who is at risk for contracting measles?

Measles is one of the most contagious viruses, with more than 90% of unvaccinated people who are exposed to it experiencing infection. As Dr. Pallavi Aneja, program director of Internal Medicine Residency at HCA FL Northwest and Westside Hospitals told CBS News, the virus can lead to later health problems and in some cases can cause death: “At times, rarely can [the disease] cause a very serious illness, which can affect the brain maybe even after five to seven years after measles,” Dr. Aneja said, adding measles “can cause something called panencephalitis—which is a brain infection—which could be fatal.”

While you might be up-to-date on your shots, some of the most vulnerable—that is, children—have to wait until specific ages to be fully vaccinated. A baby will typically get its first dose between the ages of 12 and 15 months and a second before kindergarten. Unvaccinated children are said to be the most vulnerable population for this disease which presents with a high fever cough, and runny nose, followed by the tell-tale measles rash. Measles can cause other complications such as ear infections, pneumonia, and encephalitis, and has a fatality rate of 1 in every 1,000 cases.

Adults who are vaccinated against measles can contract it, but the CDC suggests risk is very low.

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The current risk for measles

Experts say that when more than 95% of the population is inoculated against measles, there is typically little risk for children—but waning vaccination can put them in danger. A person is considered protected when they have had both MMR doses, according to the CDC, though one dose reportedly offers up to 93% protection.

During one of the largest domestic outbreaks in 2019, more than 1,200 people contracted the virus. While today’s numbers haven’t reached that level, the CDC has launched an initiative to get measles vaccinations on track and keep eradicated diseases in the past, where they belong.