The future of American health care may be shaped by a significantly less robust childhood vaccination schedule, especially now that President Trump has embraced rhetoric previously confined to anti-vaccine activists.

Why it matters: Less vaccination opens the door to a lot more infectious disease and its long-term ramifications, public health experts say.

• And complicating any effort to forecast how this all plays out is that it's not particularly clear which vaccines Trump would drop from the government's recommended list.

Driving the news: Trump, asked by reporters about the review of the childhood vaccination schedule that he ordered last week, said that "we're going to reduce it very substantially."

• He referenced "88 different shots" children now receive when, in reality, it's more like 54 doses by age 18, including annual flu shots.
• In the memo ordering the review, Trump directed health officials to "review best practices from peer, developed countries for core childhood vaccination recommendations."

Between the lines: The obvious question — to me at least — is which vaccines Trump and other health officials are concerned about.

• Some are obvious; the CDC advisory committee has already voted to change the recommendation that newborns universally get vaccinated for hepatitis B, for example.
• The FDA's top vaccine regulator has linked the deaths of 10 children to COVID vaccines, a claim he hasn't yet offered evidence to substantiate.

Yes, but: Figuring out if there's a problem with the vaccine schedule depends on which country you're comparing the U.S. with, or even which genre of vaccine concerns you're talking about.

• While the U.S. is certainly on the hefty end of the spectrum, we're not alone there. Countries like Australia have vaccine schedules pretty similar to ours.
• Others, like Denmark — which was singled out by Trump and in discussions by CDC vaccine advisers — vaccinate every citizen against significantly fewer diseases.
• Public health experts point out that Denmark is many times smaller than the U.S. and, unlike us, has a national health system, among other differences.

But where the U.S. stands in relation to other developed nations isn't the only avenue of concern being explored by the administration and its advisers, many of whom lack formal backgrounds in vaccine science.

• Vaccine ingredients and even the FDA's approval processes have also come under fire, which further expands the potential list of vaccine targets.

The other side: "There [are] no problems that are being solved," said Peter Hotez, a vaccine scientist and professor at Baylor College of Medicine.

• "They just sit and scour the landscape for any excuse they can to disrupt the childhood immunization and vaccine schedule," he added.
• "So I think you have to be very careful in giving too much credence to their reasons for it. They're all contrived reasons. These are not good-faith actors."

There's been a lot of ink spilled already on how the U.S. is not Denmark. And it's true, one of those differences is that Denmark's childhood vaccine schedule includes shots against seven fewer diseases than the U.S. schedule.

• Those diseases are RSV, hepatitis B, rotavirus, flu, chickenpox (also called varicella), hepatitis A and meningococcal disease.

Yes, but: There's not that large of a gap between the U.S. and all of its peer countries, as the Washington Post found in this helpful review.

• The U.S. only recommends routine immunization against two more diseases than Australia (RSV and hepatitis A, which Australia only recommends for certain populations), one more than Canada (which also only recommends hepatitis A shots for certain populations) and two more than Britain (which doesn't include RSV or hepatitis A).
• The review didn't include COVID vaccines.
• "There's not a whole lot of daylight between the United States and other developed countries," Hotez told me.

There's also the question of timing, which can vary by country.

• While the U.S. recommends all infants receive a birth dose of the hepatitis B vaccine — at least unless the CDC adopts the recommendations passed by the advisory committee last week — Britain recommends it at 2 months for all babies who are born to women who don't have the disease.
• Britain, like Denmark and unlike the U.S., has a national health system.

What they're saying: Vaccine guidance "may differ by country due to different disease threats, population demographics, health systems, costs, government structures, vaccine availability, and programs for vaccine delivery," the American Academy of Pediatrics writes in a fact check of vaccine criticisms.

The umbrella of which vaccines may end up in the Trump administration's crosshairs gets much wider if you look beyond comparisons with Denmark.

Where it stands: The second day of last week's CDC advisory committee meeting offered clues to where this all may be going.

• Aaron Siri — a vaccine injury lawyer with personal ties to Health Secretary Robert F. Kennedy Jr. — gave a lengthy presentation on the childhood vaccine schedule.
• He implied that the vast majority of childhood shots haven't been adequately tested for safety, a claim which experts in the field say is false (and self-serving, given how Siri makes a living).
• Siri's claims about vaccine safety data gaps have been thoroughly refuted.

The committee also heard a presentation on aluminum salts' inclusion in some vaccines to help boost the body's immune response, which Trump himself called out in September.

• Committee vice chair Robert Malone said on a MAHA Action Zoom call this week that many childhood vaccines contain aluminum salts, and the cumulative effect of that exposure is toxic.
• "That has to be reevaluated and it has to be stopped," he said.

Reality check: Childhood shots that contain aluminum salts include DTaP, hepatitis A and B, HPV, pneumococcal and meningococcal vaccines.

• A recent review published in Pediatrics found that "aluminum-containing vaccines provide clear benefits, with risks largely limited to transient local reactions and no systemic toxicity signal."

The bottom line: These roads could lead to a lot of places. Most of the public health community isn't very happy about any of them.