Health experts worry about drop in NH measles vaccination rates
Mar. 21—With the number of measles cases on the rise globally and nationally, New Hampshire health officials are worried about a drop in the rate of kids getting vaccinated against the highly contagious illness.
Measles was declared eliminated in the United States in 2000, according to the Centers for Disease Control and Prevention.
But as of mid-March, 58 measles cases have been reported in 17 states, including Pennsylvania and New Jersey in the Northeast. That's the same number of cases reported by 19 states and the District of Columbia in all of 2023.
Measles is extremely contagious — moreso than COVID-19 or influenza, said Dr. Benjamin Chan, the state epidemiologist. That makes it a potential threat to anyone who isn't immune or protected by vaccination.
"It's one of the most contagious diseases that we have to deal with in public health and in the medical community," Chan said. "Even a single case of measles, even a single introduction, has the ability to spread very easily to other people who are not vaccinated, and that can set up an outbreak that can be very difficult and costly to control."
According to the CDC, measles symptoms appear seven to 14 days after contact with the virus and typically include high fever, cough, runny nose and watery eyes. A distinctive rash appears three to five days after the first symptoms, and infected people can spread measles to others from four days before through four days after the rash appears.
Measles is an airborne disease, Chan said. "It doesn't just take close prolonged contact, like we sometimes talk about with other diseases," he said. "Simply sharing the air with somebody with the measles virus infection is enough to cause infection.
"So people, through coughing and talking, even breathing, can aerosolize the virus, and that virus can remain suspended in the air for up to two hours after somebody leaves that airspace," he said.
"It's very, very contagious, and very, very infectious. Which means that people that don't have protection and immunity are very, very susceptible to getting the virus if somebody with measles has been in their general airspace."
In New Hampshire, children must get certain vaccinations, including measles-mumps-rubella (MMR), to enroll in childcare or school, unless they have medical or religious exemptions.
Children should get a first dose of MMR vaccine between 12 and 15 months of age, and a second dose between 4 and 6 years old, Chan said. "Those two doses are expected to produce lifelong immunity," he said. "It's just one of the most effective vaccines that we have."
Many older adults are immune to measles, Chan said, because they were exposed years ago when the disease was more prevalent. But it's critical to make sure that little kids get the two-dose vaccine series, he said.
"The larger the number of people who are unvaccinated, the more likely the virus is to cause an outbreak and be spread person-to-person," he said. "The best way to prevent infection and further spread of infection is the vaccine."
Compromising "the herd"
The target for what epidemiologists call "herd immunity" for measles is a 95% vaccination rate, Chan said.
But the level of MMR vaccination reported by New Hampshire child care centers has dropped below that rate in all but two counties, according to the most recent data collected by the state Division of Public Health Services.
Statewide, the rate for MMR vaccination at child care centers for the 2023-24 school year is 92.6%. That's down from 95% the previous two school years, when most counties reached or exceeded the 95% goal.
For the 2022-23 school year, only Coos (92%) and Rockingham (94%) counties were below target.
But this year, Merrimack County had the lowest MMR vaccination rate, just 90.1%. Coos (90.4%) and Hillsborough (90.7%) also were significantly below the desired level. Only Strafford (96.6%) and Sullivan (97.5%) currently meet the target for vaccinations.
DHHS also tracks how many school-age children are up to date on their vaccines, but the data is not broken down by individual vaccines.
For the 2023-2024 school year, 89.9% of kindergarteners in public schools were up to date on all vaccines, including MMR, and another 4.3% were "conditionally enrolled," meaning they were scheduled to get their shots. For private schools, 80.3% of kindergarteners were up to date on vaccines, and 3.6% were conditionally enrolled, while 12.3% had religious exemptions.
A worrying decline
The decline in MMR vaccination rates for kids worries Chan, who helped shepherd the state through the worst of the COVID pandemic. "The lower those vaccination numbers are, the higher the risk for measles coming into our state and then spreading and causing an outbreak," he said.
Dr. Jaisal Pragani, a pediatrician with Dartmouth Health Children's in Manchester, said he speaks with parents about the required vaccinations at well-child checks. "There are some families that have some hesitancy, and some refusal, but those are few and far between," he said.
Some of the decrease in vaccination rates may be lingering delays from the pandemic years, Pragani said. "The pandemic threw a big monkey wrench in families getting in for their updated shots," he said. "So that's probably part of it, just playing catchup with some of those families that missed their vaccine schedule."
But misinformation also is playing a role, Pragani said. He has heard parents voice concerns about alleged links between vaccines and autism, and about aluminum in the vaccine itself.
Studies have proven no link between the MMR vaccine and autism, he said. And the amount of aluminum in the vaccine — it's used as an "adjuvant" to boost the efficacy of the vaccine — is lower than what's found in groundwater, formula and breast milk, he said.
"The vaccine is safe," Pragani said. "It's been around for 30, 40 years."
Recent U.S. outbreaks
Measles outbreaks have been reported in the United States in recent years.
In 2019, a total of 1,274 cases were confirmed in 31 states, the highest number since 1992. The CDC reported that the majority of cases were among people who were not vaccinated, including two outbreaks in Orthodox Jewish communities in New York.
An outbreak that sickened 125 people was related to visits to Disney theme parks in California in late 2014 and early 2015. Again, most cases were in unvaccinated individuals.
Most U.S. cases this year — 54 — have been linked to international travel, and most were in children who had not received the MMR vaccine, according to the CDC. The agency on March 18 issued a Health Advisory, recommending that all U.S. residents older than 6 months "without evidence of immunity," who are planning to travel internationally should receive MMR vaccine at least 28 days before they leave.
The last time a New Hampshire resident was diagnosed with measles was in 2011, according to Chan. The state health department has issued alerts since then after someone with a confirmed case of measles traveled here, but no local cases were reported.
But with measles on the rise globally, and the number of outbreaks increasing in this country in recent years, "That's certainly something that may happen in New Hampshire and is something we're monitoring," Chan said.
Some people may discount measles as just another childhood illness that kids get, and get over, quickly. And the vast majority of kids will recover in about a week, Pragani said. But some may develop complications that are serious or even life-threatening.
Epidemiologist Chan said one in five people who are unvaccinated and get measles will need to be hospitalized. One in 20 children who get measles will develop pneumonia, and one out of 1,000 will develop encephalitis, swelling of the brain. "It's those more serious forms, the pneumonia and brain infection, that can cause people to die from their infection," Chan said.
The trust factor
Pediatrician Pragani said he's never seen a case of measles in his practice — just in medical textbooks. He wonders if that may help explain why some parents aren't as worried about the illness as in generations past.
"It's easy to dismiss something when it hasn't been a big issue," Pragani said. "But if vaccine rates decline, then it's very possible that we'll start seeing these things again."
"There's a lot more international travel, so if we don't get our population vaccinated, we're more susceptible as a population to having these pocket outbreaks," he said. "And certainly, if one kid gets it, it's a very fast-spreading disease, so it's hard to keep in check."
Chan urges parents to turn to their pediatricians for accurate information about measles and vaccines. "I think it's understandable that parents have questions and concerns, and the best place for those questions and concerns to be answered is with a trusted primary care provider," he said.
But Pragani said he's concerned that the growing level of misinformation out there will lead to a breakdown in trust between families and health-care providers.
"Honestly, the worry is that we lose families to just not coming in and having these discussions," he said. "If there's a breakdown in trust, and they stop coming even for their well checks, it's harder to educate, and it's harder to discuss, and it's harder to make a plan based on what their concerns are."
