Childhood vaccination rates have markedly declined across the U.S. since the start of COVID, according to new Johns Hopkins University showing 78% of more than 2,000 counties reported drops and the average immunization rate had fallen to 91% 鈥斅爁urther below the 95% threshold needed for herd immunity.

While existing Centers for Disease Control and Prevention data has historically shown broadly declining measles-mumps-rubella vaccination rates at the state and national levels, the county-level analysis published this week in JAMA is far more granular.

It provides a 鈥渂etter understanding of these pockets where you have more exceptionally high risk,鈥� said senior author Lauren Gardner, the director of Johns Hopkins University’s Center for Systems Science and Engineering.

鈥淜nowing where there are problem areas,鈥� she added, 鈥済ives policymakers and public health professionals locations to target their limited resources to try and improve vaccination coverage and therefore minimize the potential risk of measles outbreaks.鈥�

The country is currently experiencing a deadly measles outbreak that has infected over people across 30 states and killed two unvaccinated children. Case numbers this year have already surpassed 2024鈥檚 total and mark the second-highest number of confirmed cases in a year since the disease was declared eradicated in the U.S. in 2000. Some 96% of reported infections have involved a person who was unvaccinated or whose status was unknown and 13% have resulted in hospitalization.

Gardner, who also led the data collection efforts behind , and her team collected county-level, two-dose MMR vaccine rates for kindergarteners from each state’s department of health website from 2017 to 2024, where available. Ultimately, they were able to analyze trends in 2,066 counties across 33 states and made all their data available to download.

While state level average rates may decline by a few percentage points, the researchers found 130 counties where they dropped by at least 10 percentage points, and in 15 of those counties, they plummeted more than 20.

Only four of the states studied 鈥� California, Connecticut, Maine and New York 鈥� reported an increase in the median county-level vaccination rate. They are currently the only four states that exclusively allow medical 鈥� and not philosophical or religious 鈥� exemptions to mandatory vaccines for school-aged children.

Gardner said she pursued the county-level data after observing growing vaccine hesitancy and misinformation. Based on her years of work in the field, she said she was 鈥�100% expecting to see [these current outbreaks].鈥� 

If vaccination rates continue to drop 鈥渕easles is likely to return to endemic levels in the US,鈥� according to the Johns Hopkins鈥� report 鈥� a concern other experts see as heightened by Robert F. Kennedy Jr. now heading the U.S. Department of Health & Human Services. A well-known vaccine skeptic, Kennedy initially the measles spread in late February and has been in his support of the MMR vaccine.

Under Kennedy鈥檚 leadership, the Trump administration released the controversial 鈥淢ake America Healthy Again鈥� on May 22, which misinterpreted studies, and is suspected of being generated in part . The report, which involved , questions the safety and importance of some childhood vaccines.

鈥淒espite the growth of the childhood vaccine schedule,鈥� the report reads, 鈥渢here has been limited scientific inquiry into the links between vaccines and chronic disease, the impacts of vaccine injury, and conflicts of interest in the development of the vaccine schedule.鈥� 

Paul Offit, the director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and a professor of pediatrics at the University of Pennsylvania Perelman School of Medicine, pushed back on these assertions.

The issue has been well studied, and there is no evidence of links between childhood vaccines and chronic diseases 鈥� including diabetes and autism 鈥� said Offit, who is also member of the Food and Drug Administration鈥檚 Vaccines and Related Biological Products Advisory Committee.

He referenced 24 studies across seven countries and three continents involving thousands of children that show they鈥檙e at no greater risk of developing autism if they receive the MMR vaccine.

Current skepticism is not isolated to the measles vaccine: The Food and Drug Administration, which falls under HHS, recently released which no longer recommends the COVID vaccine for healthy children or pregnant women. In response, a top COVID vaccine adviser at the CDC resigned this week, according to reporting from  

And across the country, numerous states have introduced legislation to loosen vaccine requirements for school-aged children, opening the door for more parents to opt their kids out.

鈥淚 think this is only going to get worse,鈥� Offit said. 鈥淚 think vaccines are under attack. You have a secretary of Health and Human Services who will do everything he can during the years that he is in that position to make vaccines less available, less affordable and more feared. 鈥� So I think this is a dangerous time to be a child in the United States of America.鈥�

Correction: In a previous version of this story, we incorrectly characterized Dr. Paul Offit鈥檚 status on the CDC鈥檚 Advisory Committee on Immunization Practices. He is a former voting member of the CDC鈥檚 advisory committee and a current member of the FDA鈥檚 vaccine advisory committee.

According to by the Centers for Disease Control and Prevention, body mass index (a common measure of weight relative to height) in a sample of 430,000 children increased between March and November 2020 at nearly double the rate that it did before the pandemic began. The changes were especially prevalent among elementary-aged children, as well as those who were already overweight or obese.

Get stories like this delivered straight to your inbox. Sign up for 蜜桃影视 Newsletter

Dietician Michelle Demeule-Hayes, the director of at Baltimore鈥檚 Mt. Washington Pediatric Hospital, called the trends 鈥渟taggering.鈥�

鈥淚t鈥檚 never been this bad,鈥� she added. 鈥淪o the research is definitely accurate.鈥�

The CDC鈥檚 findings echo those of other research released in the past few months. by the Journal of the American Medical Association (JAMA) showed that rates of overweight and obesity have soared among children measured in California between the ages of 5 and 17. Two others 鈥� one and appearing in the journal Pediatrics 鈥� found that the weight gain was greater for certain demographic subgroups, including Hispanic, African American, publicly insured, and low-income children.

The spate of publications suggests a national spike in pediatric weight gain as kids have been restricted in their movements outside the home.

Corinna Koebnick, a nutrition scientist at Kaiser Permanente Southern California and a co-author of the JAMA paper, wrote in an email that it was 鈥渟afe to say鈥� that children have gained weight during the pandemic, and that it was unclear whether opening schools to in-person learning will be enough to reverse the trends that have taken hold.

鈥淭he increase in obesity over the 11 months [we] analyzed compares to the increase seen in national data over almost the last two decades,鈥� Koebnick said. 鈥淐hildren who have social and financial disadvantages, who live in school districts with less money or…less access to parks and meal programs may have additional challenges returning to healthy weights.鈥�

Koebnick鈥檚 study used Kaiser Permanente electronic health records for over 190,000 children whose body-mass index (BMI) was measured during a medical visit both before and during the pandemic. Researchers divided patients into three age groups (those between the ages of 5 and 11, 12 and 15, and 16 and 17) and studied their tendency to be overweight (at or above the 85th percentile of BMI for age) or obese (at or above the 95th percentile.)

Children in all three age groups gained more weight during the pandemic than they did before. But elementary-aged kids saw the biggest relative gains, with an average increase of BMI of 1.57, compared with an increase of 0.91 for the next-youngest group and 0.48 for the oldest. Adjusted for height and translated into actual weight, those figures indicate average gains of 5.07 pounds, 5.09 pounds, and 2.27 pounds for the respective groups.

Overall, the portion of 5-11-year-olds who are classified as overweight or obese is now 45.7 percent, up from 36.2 percent before the pandemic. The same figures rose by 5.2 percent among 12-15-year olds and 3.1 percent among 16- and 17-year-olds.

Demeule-Hayes, said that the wave of research on pandemic-related weight gain reflected the reality she and her colleagues face every day. Some patients referred to her, none older than 17, weigh as much as 400 pounds, and it has become typical to treat children diagnosed with what are typically seen as adult ailments, such as hypertension, high cholesterol, diabetes, and osteoarthritis.

Several papers already showcased the rising prevalence of type-2 diabetes. In both Washington, D.C., and Baton Rouge, Louisiana, researchers discovered that pediatric diagnoses of the dangerous and chronic condition approximately doubled in the year after school closures began. Among children diagnosed during that period, one study found that 60 percent required hospitalization for complications like severe hyperglycemia, compared with just 36 percent in the year before COVID emerged.

But Demeule-Hayes said that another common health complication of obesity, obstructive sleep apnea, poses particular risks for K-12 students.

鈥淭here are a whole lot of sleep disturbances with these kids because they’re tired, they’re not getting good-quality REM sleep,鈥� Demeule-Hayes said. 鈥淪o they’re coming home and taking naps, which just perpetuates that sleep-disturbance cycle 鈥� they can’t get to sleep later because they’ve taken a three-hour nap after school.鈥�

Experts are still investigating how the coronavirus changed the lifestyles of both children and adults. have shown that sales of packaged and processed foods shot up in the early months of the pandemic, and suggests that consumption of fresh foods declined. Demeule-Hayes pointed to the monthslong stillness that followed school closures, during which she watched her own young children learn from inside the house.

“Having them be on a computer literally all day, not having any of the recess or the steps outside or even just walking up and down the halls 鈥� they’ve been so, so sedentary,鈥� she lamented. 鈥淧re-pandemic, even if they were getting driven to school, they were still at least walking around the school and walking up one or two flights of stairs to classrooms.

According to tech firm SuperAwesome, the time children spent on screens each day after COVID-related closures began; 40 percent of kids aged 3-9 said they spent 鈥渕uch more鈥� time on screens. Respondents to of Canadian youth reported lower levels of physical activity, less time spent outside, more sedentary behaviors, and more sleep than before the pandemic.

As school districts around the country reopened for full-time, in-person learning, educators have welcomed back students whose lives were meaningfully 鈥� and perhaps permanently 鈥� altered by COVID. The extent of the academic damage is thought to be extensive, and hospital records suggest that many children may have suffered prolonged abuse while separated from their schools. On top of those severe setbacks, the bodily changes that some have undergone may prove long-lasting: Obese children and adolescents are as adults.

Koebnick recommended that parents limit screen time and encourage their kids to exercise and drink lots of water. Demeule-Hayes said that she recognized that some parents might still be leery of outdoor play given the dangers of the Delta variant. Still, she said, there was much that families and educators could do to combat further weight gain.

鈥淎s much as teachers and administrators can work [movement] into school time, they should. For parents, it’s taking walks as a family, after dinner, whenever you can work it in. Our message is always to make changes as a family so there’s not a stigma around a child’s ‘weight issue’; it’s really about making healthy changes for the family.鈥�