Measles At Highest Levels Since 2019: What To Know In MA

MASSACHUSETTS — An acceleration of measles cases, the highest since 2019 with 125 infections in several states but not yet in Massachusetts, represents “a renewed threat to elimination” of one of the world’s most contagious diseases, the Centers for Disease Control warned in a recent report.

States with infections include Arizona, California, Florida, Georgia, Illinois, Indiana, Louisiana, Maryland, Michigan, Minnesota, Missouri, New Jersey, New York, Ohio, Pennsylvania, Virginia and Washington.

Massachusetts hasn't had any reported measles cases so far this year, according to the CDC’s latest surveillance report.

Most of the reported measles cases, anywhere from 50 to 99, are found in Illinois. Florida has the second-highest number of reported cases at a significantly lower number of between 10 and 19.

Most of the measles cases this year are linked to international travel, and the majority are among people who haven’t had measles, mumps and rubella (MMR) vaccinations, the CDC said. Also according to the latest tally of cases:

• 46 percent (57) of the cases are among children 5 and younger;
• 32 percent (40) are among people who are 20 or older; and
• 22 percent (28) are between 5-19 years old.

More than half (54 percent) of those who have gotten sick with measles have required hospitalization and isolation for the management of complications, the agency said.

Massachusetts is among the states that require MMR vaccinations for anyone in kindergarten through 12th grade, plus some healthcare workers. Pockets of the country continue to have low vaccine coverage, leaving some areas at higher risk for outbreaks.

As of the beginning of the 2022-23 school year, 93.1 percent of incoming kindergarten students had received the necessary doses of MMR vaccine, according to CDC estimates. In Massachusetts, 96.5 percent of kindergarteners entering public school received their MMR shots, according to the estimates. In general, herd immunity happens when 95 percent of a given population has been vaccinated.

The 2019 outbreak was the worst in almost three decades, with 1,274 reported for the year, with two in Massachusetts. It has threatened the nation’s status as a country that has all but eliminated measles by stopping its spread through vaccinations.

Even if the trend of 125 cases per quarter continues, 2024 still won’t surpass the 667 cases reported in 2014, according to CDC data. But measles outbreaks don’t fit neatly into quarterly averages, and the number of cases in the first three months of 2024 is 17 percent higher than in the same period in the previous three years.

Measles is common in many parts of the world. In the current outbreak, unvaccinated Americans traveling to the Middle East and Africa brought the measles home, the CDC said.

But more than half of this year’s cases come from a Chicago outbreak largely involving people who lived at a migrant shelter.

Measles is a highly contagious virus that spreads when people who have it breathe, cough or sneeze, or through contaminated surfaces. The hardy virus can linger in the air for two hours. If exposed, 9 out of every 10 people who are susceptible will get the virus, according to the CDC.

Before vaccines were introduced in 1963, measles was a childhood illness most kids got. In the pre-vaccine years, between 3 million and 4 million measles cases were reported a year. Although most people recover, it’s a dangerous disease for others, according to the CDC.

The agency said that in the decade before vaccines were available, 48,000 people a year were hospitalized, about 1,000 a year developed dangerous brain inflammation from measles and between 400 and 500 people died every year from measles.

Measles was declared eradicated in the United States in 2000.

The Associated Press and Patch's Neal McNamara contributed reporting.