The U.S. is experiencing the worst measles comeback in decades, and the illness is popping up in spots where crowds gather — trains, sports stadiums, bars. This has prompted some travelers to question whether their upcoming trips are safe.
As of Sept. 24, the CDC has recorded more than 3,600 confirmed measles cases across the U.S., including two deaths reported by Sept. 28. Nearly every single one of those cases has been found among individuals who never received the vaccine.
The Case Count and What It May Be Missing
As more information arrives and after completing additional reviews, the CDC says the death count remains subject to change. Four deaths have been recorded by the Pennsylvania Department of Health and linked to measles. The CDC has challenged whether measles was the actual cause of those deaths.
According to the Johns Hopkins Bloomberg School of Public Health U.S. measles tracker, Pennsylvania, Ohio and New York have led the nation in cases over the past two weeks.
The director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and a professor of pediatrics at the Perelman School of Medicine at the University of Pennsylvania says the official figures fall short. He is Dr. Paul Offit, and he argues that the reported totals do not capture the full extent of the issue.
“I think if anything, we’re underestimating how many people are actually being exposed, and how many people are being infected, and how many people are being hospitalized and dying,” he said.
He also noted that many children, parents, or adults do not seek medical care when they become infected.
How Measles Spreads and Why It Is Hard to Track
Measles moves quickly from person to person. It gets passed along through the air when a sick person coughs, sneezes or breathes. You don’t need to touch someone who has it to get it either — simply being near where they were within two hours of them being there is enough to catch it.
One person with measles can infect roughly 15 to 18 others if they are susceptible, Offit said. Susceptible means people who’ve never had measles or who are unvaccinated. Among those exposed, up to 9 out of every 10 will catch it.
That explains why exposures keep turning up in crowded places.
What an Exposure Notice Means
Cases grouped together in one place over a set amount of time make up an outbreak, per George Mason University College of Public Health epidemiologist Amira Roess. When a person encounters someone carrying measles, that counts as an exposure, she says.
People in California have been told about possible exposures following the travel of an infected and unvaccinated train and bus rider who crossed the United States and passed through several California counties. In St. Louis, the City’s Department of Health asked residents to look out for signs of illness after someone who visited local bars and a sports stadium came back with measles.
The difficulty in tracking measles stems from how its symptoms show up: fever, cough and rash usually start seven to 14 days after exposure, though they can appear as late as 21 days afterward. When a case is confirmed, public health officials interview the patient about where they went and who they saw during the period they were spreading the virus, which generally covers four days before the rash becomes visible.
“So it’s a really labor-intensive process,” said Dr. Kalyani McCullough, who leads the Vaccine Preventable Disease Epidemiology & Control Section of the Immunizations Branch of the California Department of Public Health.
If someone has been around a person with measles, they should look for signs of illness within three weeks and call a doctor if any appear. People who have not had the vaccine can be asked to stay away from others and may be checked by public health workers to see whether they become ill.
The Shot That Protects Against Measles
People who’ve had two doses of the MMR vaccine are considered protected against measles. The first dose is usually given at around 12 months.
Every expert who spoke with NPR pointed to one thing above all else for staying safe from measles: making sure your vaccinations are up to date.
Being fully vaccinated against measles, mumps, and rubella means receiving two doses of the MMR vaccine, which is typically given during childhood. If you’re not certain about your vaccination history, your healthcare provider can confirm it for you. Based on your records and any recent health concerns, they might suggest a booster shot.
This applies to people arriving in the U.S. from abroad, Offit explained.
He spoke those very words, saying “I think anybody who is traveling from another country into the United States should make sure they’re up to date on their vaccines, because it’s dangerous to be in the United States now if you are not fully immune to measles,”.
Offit pointed out that numerous individuals with compromised immune systems cannot receive vaccinations unless they have already done so. These people often depend on herd immunity to stay safe — the safeguard against illness that arises when enough members of a population are inoculated. With measles, that critical number stands at 95%.
According to the CDC, the percentage of kindergartners who received required vaccinations fell to 92.4% last school year.
The Toll of the Disease
McCullough said measles is not “just a fever and a rash.”
“It can affect a lot of different parts of the body, and it can have long-lasting effects as well,” she said. “Both with immune amnesia, which means that the measles virus can actually reduce immunity to other infections after being infected with measles.”
“So I think it’s just important for people to realize that getting measles can have some pretty serious consequences,” McCullough said.
Two deaths, reported by the CDC through Sept. 28, stand as proof of how dangerous the illness remains. Four deaths tied to measles in Pennsylvania give a sense of how heavy the cost has grown.
What Travelers Should Know
Before you set off on a trip, make sure your vaccination record is up to date.
As of Sept. 24, the CDC reports more than 3,600 confirmed measles cases in the United States, with two deaths as of Sept. 28.
- Confirmed cases: over 3,600 as of Sept. 24
- Deaths: two as of Sept. 28
- Most cases in the last two weeks: Pennsylvania, Ohio and New York
- Vaccine threshold for measles herd immunity: 95%
- Kindergarten vaccination coverage: 92.4% last school year
A resurgence of measles is happening now, and it is growing. The CDC’s tally of 3,600 cases stands as the clearest proof of that trend. Offit believes the actual total of cases nationwide probably runs even higher than what the official numbers show.
The worry that shadows this account comes from the fact that the official figures are just a beginning, not the whole story. The sickness spreads easily, is difficult to follow, and can cause lasting damage.
Measles exposure warnings carry real weight for travelers. After being told of a possible contact with the virus, keep an eye on your health for up to three weeks, watching for fever, cough and rash. Should any of those symptoms appear, stay isolated and reach out to a doctor at once.
Checking your vaccination records and getting any missing MMR shots is still the simplest way to protect yourself. The two-dose series is the best defense available, so make sure yours stays current.
Source material: “Travel plans? Here's what to know as measles exposures reach trains and games,” NPR.
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