It could be weeks before Maryland's measles exposure is fully known

BALTIMORE — It will likely be weeks before public health agencies know the full extent of measles exposure in Virginia and Maryland following the discovery of an infected person living in Howard County, officials said.

The Maryland Department of Health reported Sunday that an unidentified patient tested positive for the highly contagious virus after recently traveling internationally to an unspecified country. That person had been in the Washington Dulles International Airport, including the baggage claim area and through Terminal A on March 5 and, two days later, was in the Johns Hopkins Howard County Medical Center Pediatric Emergency Department, according to the state health department.

Public health officials are urging anyone who may have been exposed to watch for symptoms — which mimic cold symptoms, plus a high fever and rash that starts as flat, red spots — until March 26. If symptoms manifest, people should isolate themselves at home and contact a health care provider before showing up at a health center. As of Monday afternoon, no other measles infections had been reported in Maryland.

Johns Hopkins Howard County Medical Center has notified anyone who may have encountered the infected patient, according to the hospital. No new infections have been found, said spokesperson Tia Mason.

Dr. Greg Schrank, an infectious diseases expert at the University Of Maryland Medical Center, said measles typically has an incubation period of up to three weeks.

“It might be a week or longer before we start to see any exposed individuals, who develop infection, to start to present with symptoms,” Schrank said.

Will that happen? It depends, he said.

“I think it’s hard to predict. It really depends on who was exposed. One thing we can lean on a bit here in Maryland is that we generally have a very highly immunized population, especially to measles.”

Cases in 12 different parts of the country

Meanwhile, the Virginia Department of Health is working with the Centers for Disease Control and Prevention to identify people on the flight into Dulles who may have been exposed, said department spokesperson Brookie Crawford. The department declined to say how many people have been contacted.

Before the Maryland case, the CDC had tracked at least 222 measles cases in 12 different parts of the United States. The vast majority, 198, were in Texas. New Mexico has seen at least 10 cases.

This Maryland case was not connected to the Texas and New Mexico outbreaks, according to the state Department of Health.

Public health officials have provided no information on the infected Maryland resident. The Howard County Public School System sent a message to parents stating that it had not received any indication that the person was a student or staff member.

Maryland counted one measles infection last year, one in 2023 and, before that, five cases in 2019. The 2024 and 2023 cases also involved international travel, said Dr. Lucia Donatelli, who leads the Maryland Department of Health’s Center for Immunization.

“One of the messages that I really want to get out there is that, prior to international travel, when you’re planning a trip overseas, make sure you’re up to date on your vaccinations,” Donatelli said.

Swelling of the brain

While measles often looks only like a rash, it can cause a variety of health complications and even lead to death, especially in the very young.

According to the Centers for Disease Control and Prevention, symptoms of an infection typically one to two weeks after exposure to the virus. Common symptoms include high fever (sometimes 104 degrees or higher), coughing, runny noses, and red, watery eyes. A rash usually comes three to five days after the first symptoms start.

Children younger than 5, adults over 20, pregnant women and people with weakened immune systems are most likely to suffer complications. About 10% of children infected will get ear infections, and about 5% of them will get pneumonia — the leading cause of death in measles-infected young children.

In much rarer cases (about 1 out of 1,000 cases), infected children will develop swelling of the brain, which can lead to convulsions and result in deafness or permanent intellectual disabilities, according to the CDC.

Infections in pregnant women can lead to premature births and/or low birth weights.

In 2023, health experts estimate that about 107,500 people died globally from measles.

“As a mother, I know that every parent wants to do what’s best for their child; we all do,” said Monique Soileau-Burke, a pediatrician at The Pediatric Center in Columbia. “And vaccinating your children is the best way to keep them healthy, keep them safe and keep them from any long-term consequences that they may have after getting the measles or any other vaccine-preventable disease.”

‘Go out and get vaccinated’

Measles is spread through the air when an infected person coughs or sneezes. Infected droplets can remain in the room for two hours and infect those exposed to it by breathing or touching infected objects.

People with measles can spread the virus four days before and four days after a rash appears.

A single infected person can spread measles to 12-18 people who are susceptible to the virus, health experts say.

Vaccination is the best way to prevent infection. According to the CDC, two doses of MMR (measles, mumps and rubella) vaccine are about 97% effective at preventing measles; one dose is about 93% effective. Children are generally vaccinated after their first birthday but may be inoculated when they’re as young as 6 months, especially if they will travel internationally, according to the Maryland Department of Health.

Epidemiologists say that at least 95% of a given population must be vaccinated to prevent widespread infections. Federal data show that more than 96% of Maryland kindergartners had received two doses of the MMR vaccine during the 2023-24 school year — one of the highest vaccination rates in the country. The national average is 92.7%, according to the CDC.

A State of Maryland survey put actual vaccination rates among this age group during that period at an even higher 99%.

“We have very high vaccination rates in general,” said Donatelli. “Having said that, we do have pockets of the population that we know are undervaccinated. So, if you haven’t gotten the MMR vaccine and you’re not fully vaccinated, this is the time to reconsider and go out and get vaccinated.”

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(Baltimore Sun reporter Kiersten Hacker contributed to this report.)

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