America’s vaccine skepticism is starting to show up in health data

When a baby is born in a hospital in the US, one of the first things that happens — usually within 24 hours — is a hepatitis B shot, which prevents a virus that can cause liver cancer. The newborn shot has been a standard practice nationwide since 1991, after earlier efforts at prevention kept missing the mark. In the decades that have followed, most parents haven’t thought twice about it.

But over the past two years, more and more parents have started saying no. Because the birth dose is given inside the hospital, before the family goes home, there’s no appointment to miss, no chance of a scheduling mix-up — ways other childhood vaccines can be missed. If a newborn didn’t get this shot, in most cases, someone actively declined or delayed it.

A study published on February 23 in JAMA puts a clear number on that shift. The researchers tracked 12.4 million newborns — roughly a third of all US births — across hospitals in all 50 states that use Epic, one of the country’s largest electronic health record systems. Using years of prior data, the researchers modeled where vaccination rates should have been heading, and compared those projections to what was actually happening.

The study found that between 2023 and mid-2025, the share of newborns getting the hepatitis B birth dose fell from 83.5 percent to 73.2 percent. That translates to roughly “400,000 or more babies a year declining or delaying the hepatitis B [birth] vaccine,” said Joshua Rothman, a pediatrician at UC San Diego School of Medicine and the study’s lead author. For context, that’s roughly equivalent to the entire population of Minneapolis declining or delaying the shot every year.

All of this happened before Robert F. Kennedy Jr. took over the nation’s health agencies. Now, he’s turned skepticism into policy. In January, the Centers for Disease Control and Prevention stopped universally recommending the hepatitis B birth dose — along with five other childhood vaccines. Parents were already walking away from the birth dose, and now the government is too.

The easiest vaccine to attack

The roots of this go back to the Covid pandemic, which reshaped how millions of Americans think about all vaccines — not just the Covid shot.

“This is a classic example of what we in the literature have come to refer to as a Covid-19 vaccine spillover effect,” said Matt Motta, a public health researcher at Boston University who studies vaccine hesitancy. Researchers have documented distrust of the Covid shot bleeding into general skepticism of flu vaccines, childhood MMR shots, even vaccination for pets. Polls have sent mixed signals about whether that skepticism is actually changing behavior — but a study like this captures what parents are doing, not what they are telling a pollster.

The rising skepticism hasn’t hit every vaccine equally, and hepatitis B has made for an unusually easy political target. Because the virus spreads through blood and sex, skeptics have a ready-made argument: Why vaccinate a newborn for a sexually transmitted disease? “It is one of the vaccines that lends itself very well to political opposition,” Motta said. Both Kennedy and Casey Means, President Donald Trump’s nominee for surgeon general, have made this case publicly. The scientific answer — that hepatitis B can also spread during birth and through close household contact in infancy — is true, but harder to fit on a bumper sticker.

None of this is entirely new. Americans have been arguing about vaccination since George Washington’s day, when they called it inoculation. But historically, that skepticism existed outside the federal agencies. What’s different now is that “America’s leading government health agencies are populated by people who are deeply skeptical of vaccination,” Motta said. “There is, in my mind, no precedent for this.”

In January, the CDC made it official: The agency cut the number of vaccines it universally recommends for children from 17 to 11, moving hepatitis B and five others to what it calls “shared clinical decision-making” — essentially a case-by-case decision made by parents and doctors. The US has tried versions of this before, and there’s a reason we moved away from it.

In the 1980s, doctors tested only high-risk pregnant women for hepatitis B. But up to half of infections are asymptomatic, so they kept missing cases. In 1988, the country switched to testing every mother. That helped, but 50 to 100 infants were still getting infected each year — the result of mothers with false negatives, babies exposed after birth, and families who fell through the cracks. So in 1991, the US started vaccinating every newborn, and it worked. Annual infant infections dropped to fewer than 20.

The new recommendation is taking us back to the ’80s.

Supporters of the change, including Kennedy, have pointed to countries like Denmark that don’t universally vaccinate newborns for hepatitis B. But Motta said that comparison misses a critical difference: Denmark has universal tax-funded health coverage for all residents, a national vaccine registry, and the screening infrastructure to catch cases the vaccine would otherwise prevent. (The US does none of this reliably enough to do the same.)

“If you were to tell me the United States was going to make the type of investment that Denmark has in its health infrastructure,” Motta said, “then I would say, okay, let’s revisit. But that is not the reality we live in.”

That’s partly because in the US, vaccines have long served as a kind of substitute safety net — what David Wallace-Wells, writing in the New York Times, has called a way of “limiting the downside consequences of all of our country’s notorious shortcomings.” A hepatitis B shot at birth means it matters less whether a family member is unknowingly carrying the virus. An MMR vaccine means measles is less dangerous even for a child who is malnourished or far from a doctor.

And those shortcomings are real. More than 27 million Americans were uninsured at some point in 2024, and even within the CDC’s own perinatal hepatitis B prevention program, only 65 percent of exposed infants received the recommended follow-up blood testing. Screening-only strategies work when the system catches everyone. The US system doesn’t.

A study published in December estimated that the CDC’s changes could lead to hundreds of additional infant hepatitis B infections each year — and even that, the authors warned, is probably an undercount. Their model couldn’t factor in rising vaccine hesitancy, or the fact that babies who miss the first dose are less likely to get fully vaccinated.

And hepatitis B is just one of six childhood vaccines the CDC dropped from its recommended list, alongside rotavirus, influenza, and hepatitis A, among others.

The fallout of this change will be uneven. The American Academy of Pediatrics (AAP) has broken with the CDC and published its own vaccine schedule, keeping the hepatitis B birth dose for every newborn. Several states, including Massachusetts and New York, have said they’ll follow the AAP’s recommendations rather than the revised federal schedule. Others will likely follow the federal lead.

Polling suggests parents would follow. In a February survey by the Annenberg Public Policy Center of the University of Pennsylvania, 42 percent of Americans said they’d trust the AAP over the CDC on whether newborns should get the hepatitis B shot — just 11 percent said the CDC. A third weren’t sure — the exact group a clear federal recommendation could reach.

In just the first two months of this year, the US has recorded more than 1,000 cases of measles. The full year of 2024 had 285. And now, hepatitis B could see a similar surge. Every state with a Democratic governor has broken with the CDC guidelines and maintained the old hepatitis B vaccine recommendation, whereas most Republican-led states have not. Without a uniform federal standard, which vaccines a child receives will be shaped less by scientific consensus than by the politics of the state they’re born in.