Because measles is one of the most infectious viruses, an outbreak can happen quickly, although there is not currently an outbreak in Cook County, said Dr. Tina Tan, an infectious disease specialist at Lurie Children's Hospital.
“It would require more cases, and we don’t know whether or not there will be more cases, because this individual traveled out of the country and brought it back,” Tan said. “An outbreak is more the number of cases in an area than an absolute number.”
How people can get measles — and avoid getting it
Measles is transmitted through respiratory droplets, such as when a person sneezes or coughs, Tan said. It’s so contagious that, if present in a household setting, 95 percent of those who are not vaccinated will contract the virus, she explained.
In the U.S., most people are vaccinated against measles, mumps and rubella together, using what’s known as the MMR vaccine, with two shots, the first typically administered when a child is 12 months old and the second between 4 and 6 years old.
“The vaccine is very effective. The first dose is 93 percent effective and two doses are 99 percent effective,” Tan said.
Tan said that vaccines are safe and she attributes the increase in outbreaks to the circulation of false information, or the thought that the measles isn’t that serious of a disease because people got it in the past and didn’t die, she said.
Generally, if you’ve had the two-dose MMR vaccine as a child, that provides immunity for life.
However, some versions of the vaccination administered in the early years after its 1963 introduction are considered to be less effective than others. It was not uncommon for families to rely on exposure as a means to becoming immune, since once you’ve had
measles you are immune, Grant said.
Those born before 1957 also are generally considered immune because of outbreaks of the measles that exposed wide swaths of the population.
However, if there is an outbreak in your community and you aren’t sure if you’ve had the measles or a vaccination, a blood test can determine your immunity, or you can have the vaccination administered, Tan said.
A growing danger from measles outbreaks
One confirmed case of the measles in a county as populous as Cook isn’t cause for panic, but it does represent a shift, said Dr. Erik Johnson, a pediatrician with AMITA Health.
“One confirmed case is more than what we’re used to, since there was a period of time when we thought we had just about eradicated measles,” Johnson said.
Dr. Tan said in 2017 there were 120 cases of measles reported nationwide and 372 in 2018.
“Now, for 2019, just at the end of March we’re already at 314 cases,” she said. “That’s just for the first quarter, so you can imagine that we’re going to have a record number of measles cases this year.”
Dr. Frank Belmonte, with Advocate Children’s Hospital, said there have been at least five measles cases in Illinois already this year, and a number of outbreaks in other states.
Measles can be serious — but check before going to the hospital
Measles can look like many other common viral illnesses, said Dr. Jennifer Grant, with NorthShore University HealthSystem. That can include fever, cough, red or irritated eyes, runny nose, some congestion and a sore throat or headache. Three to five days later is when rash sets in; it usually starts on the face and progresses downward, she said.
If you believe you may have been exposed to or might have measles, you should always call a hospital before showing up to an emergency room, because just showing up can spread the disease, Tan said.
“Always call first — that’s not just at Lurie, that’s for all hospitals,” she said. “They would need to make special arrangements, which involves putting the patient in a negative-pressure room and ensuring they don’t risk exposing people waiting in the ER.”
What parents of young children can do
Grant said there can be concern for children who have not yet had their first MMR vaccine.
If your child has had the first MMR shot but has not yet had the second, it is safe to have the second vaccination administered before age 4, Johnson said, so long as more than one month has passed since the first shot.
“The first thing you should do is consult with your pediatrician. It is a requirement by the time you enter into kindergarten, but it can be done earlier,” he said. “Especially if this is happening in your community or you’re worried about exposure.”
Children less than 1 year old who have not yet had their first MMR vaccine can be at heightened risk, Grant said.
It is safe to give the MMR vaccine as early as six months, but that vaccination does not count toward the two a child must have before starting school, Tan said. She said it also explains why “herd immunity” is so important.
“In a community, 95 percent of individuals have to be vaccinated in order to maintain population immunity, that’s herd immunity, in which you basically can stop the spread and transmission of an infectious disease. With measles it tends to be very high because it’s very contagious,” she said.
Dangers to those already sick or immune-compromised
Those who are immune-compromised may not be able to have the vaccine. That includes those who were born with certain conditions as well as those who are battling cancer, for example, Belmonte said.
Aging adults and anyone with a serious health condition should ask a doctor about the safest course of action.
“That’s why herd immunity is so important,” Tan said. “These individuals can’t get the vaccine so they rely on the individuals who can to do so to protect them. Being able to get it and choosing not to is very much a selfish viewpoint.”
Chicago Tribune’s Lisa Schencker and Kate Thayer contributed.