Measles cases on the rise: What physicians need to know

Nearly 25 years ago, measles was officially eliminated in the U.S. Sadly, that did not mean measles was gone forever. That designation meant that infection had not been transmitted continuously anywhere in the country for more than a year. But measles could come back, and it has: at a “Disney on Ice” event in Cincinnati, a migrant shelter in Chicago, a hospital in Sacramento and other places.

As of this article’s deadline, the Centers for Disease Control and Prevention (CDC) has reported 58 measles cases in these 17 states:

• Arizona.
• California.
• Florida.
• Georgia.
• Illinois.
• Indiana.
• Louisiana.
• Maryland.
• Michigan.
• Minnesota.
• Missouri.
• New Jersey.
• New York.
• Ohio.
• Pennsylvania.
• Virginia.
• Washington.

That is the same number of cases of measles reported in all of 2023. And there are concerns it could be as high as the 1,274 cases that were confirmed in 31 states back in 2019—the year that holds the record for the most U.S. measles cases since 1992. 

“With measles, you always have to be concerned that your numbers can just exponentially rise because it's so contagious of a virus—it can stay in the air for two hours after the person has left the area,” said Erica Kaufman West, MD, director of infectious diseases at the AMA. “When you're talking about communal areas … it has a big potential to spread extremely fast.”

To put in plain terms just how contagious this disease is, “if you had 10 people who were unvaccinated in a room after somebody with measles walked out, nine of them would get infected,” Dr. Kaufman West said.

Meanwhile, federal health authorities encourage maintaining a target vaccination rate of 95% measles, mumps and rubella (MMR) for the best protection. But that rate has been on the decline since 2019. For example, last year the MMR immunization rate dropped to 93.1% among kindergarteners nationally. This, according to the CDC, leaves about 250,000 kindergarteners at risk of infection.

Most physicians in the U.S. have never treated a case of the measles in their career, which means many may lack familiarity with the disease. But now that it is back, here is what physicians should know about measles and the recent rise in cases as they step up to the plate to help their patients.

Proper protective measures are needed for patients who are exhibiting symptoms of measles. That is why it is important for physicians to be aware of the signs of measles.

Symptoms of measles include “high fevers. These are really high fevers of about 103º F, 104º F, 105º F in adults,” Dr. Kaufman West said. “Kids can get up that high and it’s not terribly unusual, but an adult with a fever of 103º F, 104º F is extremely unusual.”

Then there is “a rash that starts at the hairline, even behind the ears and neck, which might be difficult for patients to see,” she added, noting the rash “travels downward to the trunk and then outward to the arms and legs.”

“Something that starts on the feet and travels up—that’s not going to be measles. It really starts at the top and heads down and patients are contagious from four days before through four days after that rash starts,” Dr. Kaufman West said, noting if patients call for an acute visit “it’s always a good point to ask why, and if the fever and rash comes up, then it’s worth having a way to see them that doesn’t involve them sitting in the waiting room.”

It cannot be emphasized enough just how important it is for patients to get vaccinated against measles. That’s because “for people who are vaccinated, the risk is extremely low,” said Dr. Kaufman West. “For people who are vaccinated, I don’t think that there’s really much risk at all for going around like usual. It’s for those folks who are unvaccinated or for parents of children who are very small and not yet fully vaccinated where the risk is higher.”

“The first measles vaccine is given between 12 and 15 months, so babies who are less than 1 year old are very susceptible,” she said, emphasizing that “those parents should be asking questions at daycare or wherever they have their child care if it’s not in their own home.

“After one dose, the efficacy is 93%, which is great. A second dose is given at 4 to 6 years old, and that ups the measles vaccine efficacy to 97%,” Dr. Kaufman West added. “Then anybody who has an immunocompromising condition is also at high risk of measles even if they are vaccinated.”

Meanwhile, for “anybody born before 1957, measles was so rampant that they are considered immune by exposure,” Dr. Kaufman West said, noting that testing for immunity should be done on a “case by case basis.”

After years of declining vaccination rates, measles cases are popping up around the country. And most of the measles cases have been in young children and adolescents who were eligible but didn’t receive the MMR vaccine.

In fact, the CDC notes that about 61 million doses of the MMR vaccine were postponed or missed between 2020 and 2022 due to the COVID-19 pandemic. Coupled with the anti-vaccine sentiment that is growing, we’re seeing the ramifications of declining vaccine rates.

That is why it cannot be emphasized enough how important it is for physicians to talk with parents and their patients about receiving the MMR vaccine. The best way to fight the measles is to get vaccinated if a patient has not already. The MMR vaccine is safe and effective at preventing measles.

“The AMA urges everyone who isn’t vaccinated to get themselves and their families vaccinated against the measles,” said AMA President Jesse M. Ehrenfeld, MD, MPH. “Vaccination not only prevents infection, measles-related complications and even death, but also helps prevent further spread to loved ones, neighbors, co-workers and others in close contact.”

“We are reminding physicians to talk with their patients about the health risks associated with not being vaccinated and to make a strong recommendation for vaccinations, unless medically inadvisable,” Dr. Ehrenfeld said. “We also urge physicians to educate patients on the signs and symptoms, severity and complications of measles given that many people are unfamiliar with the impact of the disease.”

On March 18, the CDC issued a Health Alert Network (HAN) Health Advisory, warning of an increase in both global and domestic measles cases, and urging vaccination. The advisory emphasizes the importance of measles prevention, especially for international travelers 6 months or older, as well as children 12 months or older who do not plan to travel internationally.

Once a patient has been exposed to measles, “the incubation period is seven to 21 days. It’s three weeks where you have to wait, watch and wonder if you’re going to develop symptoms if you don’t have immunity,” Dr. Kaufman West said, noting “it can be a long and tedious time.”

As soon as a patient presents with a rash, they are “contagious from four days before to four days after,” she said. “After the four days of that rash starting, then you’re not considered contagious anymore.”

Physicians should test for measles “even if you have a classic case in high suspicion,” Dr. Kaufman West said, noting that “testing involves a blood sample to look for antibodies and then also the most important is getting a nasopharyngeal swab or an oropharyngeal—like a strep test.”

“The antibodies are good because it tells us if the person has immunity and what sort of stage they’re at. But the swab becomes really important because that’s a PCR [polymerase chain reaction] test,” she said. “You can get cross-reaction between different viruses, so just because the antibody test is positive, it’s not 100% knockout that this is measles, but that swab is super important for two reasons.

“No. 1, just like with COVID-19, it looks for the actual virus, so there’s no mistaking it and, No. 2, it allows health departments and even higher—CDC—to do genetic analysis to be able to say: Does this person’s virus RNA match another person’s virus RNA? And then they can track where that particular strain is spreading so that they can do better contact tracing,” Dr. Kaufman West added.

Physicians and other health care professionals are required to report measles cases to their local health department.

“So, physicians should make sure that they are gathering a decent amount of social history from the patients—where do they work or go to school, where they have traveled,” Dr. Kaufman West said. This is important “because we want to try to get ahead of this because it’s such a contagious virus.”

“You really want to be able to then reach out—if you know the person works at a particular business—and tell everybody to keep an eye out for these symptoms,” Dr. Kaufman West said. And if someone is not vaccinated and they work with this person, “we can vaccinate them and try to prevent them from getting infected.”

Anyone who has been exposed to measles and cannot readily show they have evidence of immunity against the disease should be offered post-exposure prophylaxis. The MMR vaccine is effective at preventing measles when administered to a person who is susceptible within 72 hours following exposure. Administering immunoglobulin within six days of exposure may also prevent or modify measles in those who are susceptible.

“The CDC has a great travel website and there’s a section where you put in where you’re going and it tells you everything,” Dr. Kaufman West said, noting it tells you ”what you need, what you should know. Maybe the whole country isn’t at risk, but certain pockets of it are for malaria or typhoid or those kinds of things.”

Beyond that, “anybody traveling outside the U.S. should know that they are immune to measles because it’s endemic in multiple countries around the world,” she said. While measles immunization is not something physicians need to ask about at every visit, “if you have a patient who you know likes to travel, it’s a good conversation to have.”

For physicians and other health professionals, “if they have that patient where they are concerned about measles, make sure you have an N95 because that 3% risk is still there, but it’s very low,” Dr. Kaufman West urged. “If the patient is coughing, go ahead and wear eye protection and a gown so you don’t get those secretions on you.”

“Most physicians have access to N95s or other respirators now, but … if they have a bunch of cases that go through and stock gets depleted, that can be an issue,” she said. That is why it is also important to make “sure you’re staying up to date with what’s in your stockpile—just being sure that you’ve got the necessary equipment to protect them and their staff.”

Additionally, “if you’re going to be doing swabs and all of that” for testing for measles, wear gloves too, Dr. Kaufman West said.

The measles virus can stay in the air for up to 2 hours after an infected person leaves an indoor space. For physicians treating a patient with measles, “the room needs to be left alone for two hours—assuming it’s just a regular exam room—after the patient leaves,” Dr. Kaufman West said, noting emergency departments “have negative pressure rooms and that turnaround time is about an hour or a little bit less.

“But for just a regular physician office, it’s a two-hour time, so the door should be shut, and no one should use it for two hours,” she added. “After the two hours, it’s just your normal cleaning and wiping down surfaces … because it can spread through respiratory secretions.”

“There are no good treatments for measles. We don’t have an antiviral for measles, For children with severe disease, physicians can give high dose vitamin A. That’s about all we have,” Dr. Kaufman West said. “But for post exposure prophylaxis, that’s where things like vaccination are important if they’re unvaccinated.

“Or giving someone antibodies. You can give them what’s called IVIg, which stands for intravenous immunoglobulin—sort of like the monoclonal antibodies that we heard about with COVID,” she added. “So, you give people antibodies to fight off a potential measles exposure so that they don’t get measles.”

“Once they’ve shown symptoms of measles, then the cat’s out of the bag. There’s nothing to do except supportive care,” Dr. Kaufman West said.