Childhood vaccination rates are on the decline at a time when Robert F. Kennedy Jr. could lead the Health and Human Services Department.
By Cecelia Smith-Schoenwalder | U.S. News and World Report, Jan. 2, 2025
The new year is certain to bring the spread of infectious diseases – both new and old. And several factors make 2025 ripe for transmission in the U.S., including declining childhood vaccination rates and a potential new leader of the Health and Human Services Department who appears ready to sow fresh doubt on vaccines in the next Trump administration.
U.S. health policy is likely to face close scrutiny over the next four years, particularly if Robert F. Kennedy Jr. gains Senate confirmation to lead HHS.
Kennedy, who denies being “anti-vaccine,” has long promoted false conspiracy theories about vaccines. He said in July that “there’s no vaccine that is, you know, safe and effective.”
While Kennedy has said he won’t ban vaccines – he likely wouldn’t have the authority, and any effort in that direction would prompt immediate legal challenges – he can still use his potential platform to discredit and plant suspicions about the shots, which can affect vaccine uptake. If confirmed, he would take over HHS at a time when childhood vaccination rates are declining and school vaccination requirement exemptions are on the rise. And at the same time, these pools of unvaccinated and undervaccinated children create conditions that allow infectious diseases to spread.
“The outlook for infectious diseases over the course of the next four years is a little dismal,” says Dr. Perry N. Halkitis, the dean of the Rutgers School of Public Health, breaking it down into three categories to watch: Reemerging, currently spreading and new infectious diseases.
“We have clearly infectious diseases that have been controlled for decades that may reemerge slowly, as we’re seeing with measles and what have you when people are avoiding these vaccinations for their children,” Halkitis says. “We have infections that have been around over the last couple of years, like COVID-19 and RSV, which is spreading very, very rapidly, that will continue to spread and potentially get worse and continue to cause death if people don’t keep up with their vaccines.”
And then, he adds, there are emerging infectious diseases we’re just starting to understand.
Here are five infectious diseases to watch in 2025:
Bird Flu
The Centers for Disease Control and Prevention reported over 60 cases of bird flu in humans in 2024, including the U.S.’s first “severe” infection.
The agency assesses the public’s immediate health risk from bird flu to be “low,” and it hasn’t documented any human-to-human transmission in the U.S.
Still, health experts warn it is one to keep an eye on in the upcoming year, particularly given what they see as a lackluster response from the Biden administration to the bird flu outbreak across herds of dairy cows.
“At this point it’s clear that we do not have a good handle on what’s happening with the dairy cattle-associated outbreak,” says Dr. Michael Osterholm, the director of the Center for Infectious Disease Research and Policy at the University of Minnesota. “The case numbers are increasing substantially. There is no real strategy at this point that is limiting this transmission.”
Measles
Falling vaccination rates brought on a global spike in measles in 2024, and the U.S. was no exception.
The CDC reported over 280 cases of measles this year as of early December – the highest annual case total of the last five years. Measles is an extremely infectious and potentially severe rash illness.
Most cases reported this year were among people who had not received a measles, mumps and rubella (MMR) vaccine or whose vaccination status was unknown. More than 7% of kindergartners – approximately 280,000 – did not have documentation of two doses of the MMR vaccine and “were potentially at risk for measles infection” during the 2023-2024 school year, according to a report published by the CDC.
Kennedy has specifically spoken out against the vaccine in the past. Anti-vaccine messaging from the Trump administration could potentially lower immunization rates even further, leading to more rapid spread of the disease.
“Measles is a challenge,” Osterholm says. “All the childhood immunizations are a challenge, regardless of who’s the secretary of Health and Human Services.”
Polio
President-elect Donald Trump recently said he is a “big believer” in the polio vaccine and would preserve access to it after a report that one of Kennedy’s advisers filed a petition to revoke approval for the polio vaccine in 2022.
But the Trump administration can still influence uptake of such shots via the platform that Kennedy and others would hold.
Kennedy has misleadingly suggested polio vaccines caused cancer in his generation “that killed many, many, many, many more people than polio ever did.”
“So if you say to me, ‘The polio vaccine, was it effective against polio?’ I’m going to say, ‘Yes,’” Kennedy said in July. “And if you say to me, ‘Did it kill more people … did it cause more death than averted?’ I would say, ‘I don’t know, because we don’t have the data on that.’”
Polio, a potentially fatal, paralyzing virus, is still prevalent in Pakistan and Afghanistan. As long as it is spreading anywhere, it could cause outbreaks in the U.S. among children who aren’t fully vaccinated.
And young parents don’t remember when mumps, rubella and polio were serious, active health threats, Osterholm says. “So to them, it’s almost theoretical,” he says.
Mpox
Mpox is a disease caused by a virus in the same family as the one that causes smallpox. Reported cases have mostly been concentrated among gay and bisexual men. It causes a rash and can spread through close contact with an infected person. It is endemic in parts of Central and West Africa.
Doses of the mpox vaccine, Jynneos, were previously available for free from the federal stockpile. That changed in April, and experts are concerned the cost of the shot will deter the populations who need it most. Although anyone can get mpox, men who have sex with men are at increased risk.
And the U.S. in November confirmed its first case of a more aggressive strain of mpox in California in a person who recently traveled from Eastern Africa.
“We have not been vigilant about this,” Halkitis says. “We have not been talking about it.”
Disease X
Disease X is a placeholder name for a hypothetical disease that could spread and cause epidemics or a pandemic. It’s an idea that encourages public health officials and scientists to prepare for the next outbreak.
“There are many viruses and bacteria that can infect animals, including humans,” Ana Maria Henao Restrepo of the World Health Organization said in March. “For a few we already have vaccines, diagnostics and therapeutics. We know what are the viruses that we need to be alert to, we know what are the bacteria we need to be alert to, but there are many thousands of them. So we need to have a simplified way to refer to them without knowing which one will cause the next pandemic. And we call it Pathogen X.”
It’s worth noting that a mysterious, flu-like disease recently spreading in the Congo was referred to as Disease X. Health officials have since identified the disease as a case of severe malaria.
Health experts emphasize that preparing for the next pandemic is of the utmost importance because another pandemic isn’t a question of if – it’s a question of when.
“We’re going to have another pandemic,” Osterholm says. “The pandemic clock is ticking. We just don’t know what time it is.”
