N.J.’s herd immunity from measles is gone. Get your kids vaccinated early, experts warn

Public health experts are recommending that infants aged 6 to 11 months get an early dose of the Measles, Mumps and Rubella vaccination, also known as the MMR vaccine, in addition to the two shots they get in early childhood.

Currently, public health guidelines only recommend an early additional MMR dose for infants traveling internationally.

However, New Jersey has lost its herd immunity, putting unvaccinated people, especially children, more at risk — mirroring a trend across the United States as vaccination coverage wanes and outbreaks increase, including two confirmed deaths from measles and one under investigation.

In response to what they call “a growing domestic hazard,” a group of experts is calling for the Advisory Committee on Immunization Practices to expand the recommendation of an early additional MMR dose for infants aged 6 to 11 months traveling to locations in the U.S. with measles outbreaks.

An outbreak is defined by the Centers for Disease Control and Prevention as three or more cases related cases in a community. For example, Erie County in Pennsylvania declared a measles outbreak on Tuesday.

Historically, unvaccinated children returning from international travel to regions where measles remains endemic have been the biggest source of U.S. measles cases.

“However, multiple recent U.S. measles outbreaks, coupled with low vaccination rates, signal a growing domestic hazard,” wrote authors of the article “Revising U.S. MMR Vaccine Recommendations Amid Changing Domestic Risks” in JAMA, a peer-reviewed general medical journal.

The recommendation comes at a time of increased risk in New Jersey, where the chance of catching measles is higher now than it was five years ago.

“Unfortunately, post-pandemic, as a state we have dipped below that herd immunity,” said Health Commissioner Dr. Kaitlan Baston during an April 7 Assembly Budget Committee hearing on the fiscal year 2026 budget.

Public health experts say that measles control depends on herd immunity of 95% vaccination coverage and that rate has been declining in the U.S. and in New Jersey, while the number of people going unvaccinated climbs.

The CDC recommends children get two doses of MMR vaccine, starting with the first dose at 12 to 15 months of age, and the second dose at 4 to 6 years old.

As of 2023, 93% of kindergartners in the state have received two or more doses of MMR vaccine, which is slightly above the national average of 92.7%, but still a decline from the state’s 2022-23 vaccination rate of 94.3%, according to the Centers for Disease Control and Prevention.

There are pockets of the state that have an even lower vaccination rate than the state average, said Baston earlier this month.

READ MORE: More kids are going unvaccinated in N.J. See the county-by-county list.

“I often say we’ve moved from the information age to the misinformation age. There’s so much bad information out there and it’s tough for families, right?” Baston said to lawmakers.

“But this is one thing that they could check off their worry list and just get the vaccinations their kids need and then it’s one preventable tragedy that we shouldn’t have to face,” said Baston, a primary care physician.

Just four months through the year, the number of measles cases reported in 2025 has already exceeded all those recorded in 2024. In Texas, there have also been two documented deaths, the first measles deaths in the U.S. in over a decade.

“We are very concerned that this is going to become a very big issue within the next five years,” said Assemblywoman Ellen Park, D-Bergen, during the hearing.

Measles is a highly contagious respiratory disease caused by a virus. It spreads easily through coughing and sneezing. Even after an infected person has left the room, the virus can remain present in the air for up to two hours, according to the CDC.

Before the introduction of vaccines in 1963, the CDC estimates about 50,000 people were hospitalized for measles each year and 500 people died annually from the disease, most of them children.

Even small declines in measles vaccine coverage can lead to outbreaks, public health experts say.

There may even be a higher risk of measles exposure in parts of the U.S. than other international destinations, according to public health experts. Protection for infants is critical because they face a heightened risk of severe measles-related complications, including pneumonia, encephalitis, and death, according to the CDC.

Symptoms of measles include a high fever, cough, runny nose, watery red eyes, and a red rash that begins at the hairline, according to the CDC.

The rash usually starts three to five days after the other symptoms. People can spread measles to others from four days before through four days after the rash appears.

Ninety-seven percent of the cases reported in the United States for 2025 are among people who had not received the measles-mumps-rubella vaccine or have unknown vaccination status, according to the CDC.

As of April 10, a total of 712 confirmed measles cases were reported by 25 states, according to the CDC. Of those infected, 79 have been hospitalized with two deaths.

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Jackie Roman may be reached at jroman@njadvancemedia.com.