Recent changes to vaccine and medicine recommendations in the US could undermine health messaging in other countries, experts say.

In September, the US Advisory Committee on Immunization Practices (ACIP) updated its recommendations for the combined measles-mumps-rubella-varicella (MMRV) vaccine in children and COVID-19 vaccines for all US residents.

It also indefinitely deferred a decision changing recommendations for the hepatitis B vaccine in newborns, though US President Donald Trump said in an announcement from the White House on Monday that it should be administered to kids not before they are 12 years old. Current medical advice states that babies should be immunized against hepatitis B over the course of their first 18 months.

Trump and his health officials also changed recommendations for the common painkiller Tylenol (which has the same active ingredient, acetaminophen, as paracetamol) during pregnancy and early childhood. They cited a handful of studies showing an association — but not a causative relationship — between the drug and neurodevelopment changes, including autism and ADHD, in children.

Scientific consensus currently shows that an interplay of wide-ranging genetic and environmental factors probably lead to these developmental changes, rather than a single cause such as painkiller use in pregnancy.

New vaccine and drug recommendations in US

The ACIP has altered its recommendations for the MMRV and COVID-19 vaccines.

The combined MMRV vaccine was previously recommended for children younger than 4. It is now recommended that the MMR vaccine is delivered separately from the "V" jab for varicella, which protects against chickenpox. Figures reportedly presented at the meeting showed that 85% of US children already receive these shots separately. Children who get the combined MMRV vaccine have a slightly higher risk for fever-related seizures. On the other hand, when the shots are split up, children are not protected against all four diseases until they have been vaccinated against each of them, instead of after a single combined shot.

Declines in vaccine uptake in recent years have led to two-decade highs in US measles cases, and higher-than-usual numbers globally.

The Trump administration panel did not vote to recommend COVID-19 vaccines to the general public. But they did reject restrictions that would have required a prescription to receive a COVID-jab.

After Trump linked the painkiller Tylenol to autism, the updated recommendation from the Food and Drug Administration (FDA), said the drug, which is the only readily available painkiller approved for use in pregnancy, should only be administered following consultation with a medical professional.

A nuanced perspective

Trump said the hep B vaccine isn’t necessary for infants because the disease is sexually transmitted.

While it is true that hepatitis is most often transmitted by sexual activity, or from a mother to a developing fetus during pregnancy, there are other ways. Contaminated needles are one, another is the fecal-oral route, where mouth exposure to the virus in fecal matter can lead to infection.

This is also how polio is transmitted. Cases of the disease have increased in some communities where vaccination levels have dropped.

The conflict between political messages and established health advice has been lamented by many experts following the Trump administration's announcements.

Even the Trump Administration senior health officials Jay Bhattacharya, Marty Makary and Mehmet Oz acknowledged that the connection between painkillers and autism is patchy in an op-ed in the magazine Politico.

"Despite the sharp rise in autism prevalence, there is no scientific consensus on what is causing rates to grow, and families have few effective tools to prevent or treat it," they wrote. "Acetaminophen should be used judiciously in pregnancy, and under medical supervision of an obstetrician, as a practical, prudent medical approach that balances risks and benefits."

Jörg Dötsch, director of the Clinic and Polyclinic for Pediatrics and Adolescent Medicine at Uniklinik Köln in Germany, told DW that vigilance is critical given the inconsistencies playing out between government advice and scientific consensus.

"To my mind, it’s ... important to always refer to what the international scientific community has achieved with all its research attempts and perspectives," Dötsch said.

US changes could damage global trust

Though statements from some parts of the US government's health machine have acknowledged contradictory science, they don’t carry the same heft as televised announcements by the US president.

And, as the world’s top economy and center of medical developments, funding and drug manufacture, what the US says and does can affect perceptions abroad.

"What happens in Washington echoes in Lagos, Nairobi, Cape Town and other places," Charles Shey Wiysonge, a senior director at the South African Medical Research Council, told DW.

He said there was a risk that vaccine debates in the United States could undermine trust in health recommendations elsewhere.

Julie Leask, a social scientist specializing in immunization at the University of Sydney, sees the same risk in Australia.

"People are trying to make sense of all this noise coming out of the US. They want to do what’s best for their health and their children’s health. It’s sad that we’re now having to warn people to be so discerning about what they will hear from the current US government on vaccines," Leask said. "There is multipartisan support for vaccination in the vast majority of countries. They are well-served by experts on their National Immunization Technical Advisory Groups who look carefully at the evidence and are committed to vaccine safety."

Dötsch recommends that people consult with a trusted medical professional when it comes to health questions. That is particularly true, he says, amid an ongoing clash between medical scientists and non-medical groups opposing vaccines and other approved therapies.

"At the end of the day, everybody has to find somebody who [they] trust," Dötsch said. "That might, for instance, be the family doctor, the GP or the pediatrician that is treating a child, or a gynecologist that is supervising the pregnancy.

"If you’re endowed with anything that comes from another country or from another society ... I’d always recommend to get in touch with those people in who you trust, and to discuss the items with them."

Edited by: Carla Bleiker