By Michael Erman, Julie Steenhuysen and Christy Santhosh

Dec 5 (Reuters) - U.S. vaccine advisers on Friday scrapped a long-standing recommendation that all American newborns receive the hepatitis B shot, a major policy win for health secretary Robert F. Kennedy Jr that disease experts say will reverse decades of public health gains.

The committee recommended the birth dose only for infants of mothers who test positive for the virus or whose status is unknown, replacing the 1991 universal recommendation aimed at protecting all children from hepatitis B infections.

For the vast majority of children whose mothers test negative for the virus, it said parents should consult with their healthcare providers over if and when to begin the three-shot vaccine series and recommended the first dose no sooner than at two months of age.

PUBLIC HEALTH EXPERTS DECRY MOVE

Public health experts and medical groups including the American Medical Association decried the move, saying the decision creates obstacles to the vaccine and is in conflict with decades of evidence on its safety and efficacy. 

Hepatitis B infections, which can lead to serious liver disease, have fallen nearly 90% in the U.S. from 9.6 per 100,000 before vaccination became widespread to about one per 100,000 in 2018.

The U.S. Centers for Disease Control and Prevention - now run by a Kennedy-appointed acting head, Jim O'Neill, who is not a scientist - will use the committee's recommendations to set U.S. public health guidance.

The recommendations affect U.S. health insurance coverage and play a key role in assisting physicians who are choosing appropriate vaccines for patients. The trade group for insurers said they would continue covering the shot. 

"The vaccine is incredibly safe and has had a historic positive impact on public health since its inception. Rolling back the initiative to protect all children will almost certainly lead to an increase in hepatitis B cases nationwide," said Dr. Richard Rupp, professor of pediatrics at the University of Texas Medical Branch.

The American Academy of Pediatrics said it continued to support the birth dose of the vaccine.

Hepatitis B primarily spreads through blood, semen, or certain other body fluids and can be spread by close contact with people who do not know they are infected, such as caregivers or friends.

PARENTS HAVE A CHOICE

The committee's emphasis on parent choice - a key tenet of the anti-vaccine movement that Kennedy has been part of for decades - ignores the role parents already have in deciding on vaccines for their children, public health experts said.

"This will signal to clinicians that there is something wrong with the vaccine - there is not - and that there are liability risks," Dr. Demetre Daskalakis, who resigned from the CDC in August as director of the National Center for Immunization and Respiratory Diseases, said in an email. 

Hepatitis B vaccine makers Merck, Sanofi and GSK defended their products as safe, with Merck saying it was deeply concerned by the vote. Merck shares closed down 1.2% on Friday, while GSK finished 0.3% lower and U.S.-listed Sanofi shares ended up 1.3%.

The World Health Organization recommends all babies receive the hepatitis B vaccine as soon as possible after birth, followed by two or three doses of the shot at least four weeks apart. It says 95% of infected newborns will go on to develop chronic hepatitis.

KENNEDY HAS BEEN REMAKING VACCINE POLICY

Kennedy, who founded the anti-vaccine group Children's Health Defense, in June fired the committee's previous 17 independent experts and replaced them with a group that largely supports his views, as part of an effort to remake U.S. vaccine policy. 

This is the most far-reaching of his changes since taking office, which include dropping broad recommendations for the COVID vaccine, cutting funding for mRNA vaccines, and advising pregnant mothers against taking Tylenol, stating without scientific proof that studies suggest a link to autism.

Children's Health Defense President Mary Holland applauded the change, saying the universal recommendation was flawed while questioning the value of the vaccine for any infant.

Several U.S. lawmakers said Kennedy and President Donald Trump would be responsible for the reintroduction of infections and disease for which there is a vaccine with well-established safety and efficacy.

"As a liver doctor who has treated patients with hepatitis B for decades, this change to the vaccine schedule is a mistake," said Republican Senator Bill Cassidy, whose vote helped to affirm Kennedy's nomination to his role. He urged CDC chief O'Neill to retain the current recommendations.

COMMITTEE CRITICIZES SAFETY DATA

Many of Kennedy's committee members criticized the vaccine as unsafe, despite decades of evidence to the contrary.  

"People should be very, very suspicious when people tell them that something is safe, especially a vaccine," said committee member Retsef Levi, a mathematician at the Massachusetts Institute of Technology.

They also said the universal U.S. recommendation was out of step with peer countries, particularly Denmark.

After the announcement, Trump signed an order directing his administration to consider aligning immunization practices with those of "peer, developed countries." On social media, he called the current U.S. vaccine schedule "ridiculous." 

Adam Langer, a CDC disease expert on staff for nearly 20 years, said during his presentation that the U.S. is not comparable to the 6 million-population Denmark with universal healthcare and more thorough screening for the virus.

According to the European Center for Disease Prevention and Control, most European countries do not recommend a universal birth dose but do recommend one at age two or three months. Only Denmark, Finland, Hungary and Iceland advise hepatitis B vaccination only for a selective group. 

The committee also voted to recommend that parents test children for hepatitis B antibodies before deciding to give subsequent shots. Under the scrapped recommendation, the birth dose is followed by two more vaccines, at one to two months and at six to 18 months. The committee did not offer a new schedule for follow-on shots.

Two members of the committee argued strongly against the changes and against doctors testing children for a level of immunological response that has not been studied.

"We will see more children and adolescents and adults infected with hepatitis B," said Joseph Hibbeln, a former National Institutes of Health official on the panel.

(Reporting by Christy Santhosh, Mariam Sunny and Kamal Choudhury in Bengaluru, Michael Erman in New Jersey, Julie Steenhuysen in Chicago, Chad Terhune in Los Angeles and Nancy Lapid in Phoenix; Editing by Caroline Humer, Bill Berkrot, Nick Zieminski and Edmund Klamann)