The Food and Drug Administration’s top vaccine regulator has declared a more stringent path for federal vaccine approvals. This decision comes in the wake of assertions from his team about a connection between Covid vaccines and the deaths of at least 10 children.

Industry experts anticipate that this new direction will complicate the vaccine approval process considerably. Dr. Vinay Prasad, who spearheads vaccine policy at the FDA, has garnered support from US Health Secretary Robert F. Kennedy Jr. In a memo distributed internally on Friday, and subsequently obtained by various media outlets, Prasad outlined a strategic shift in how vaccination programs will be approached.

Dr. Prasad emphasized that the FDA is set to reassess its annual flu-shot policies, potentially impose restrictions on simultaneous vaccinations, and demand more comprehensive safety and efficacy data from pharmaceutical companies prior to granting approval.

The memo, which has stirred significant attention, reportedly highlights a recent review that identified at least 10 child fatalities linked to Covid vaccinations. These tragic incidents are believed to be associated with myocarditis, a condition involving the inflammation of the heart muscle.

“This is a profound revelation,” Prasad stated in the memo. “For the first time, the US FDA will acknowledge that Covid-19 vaccines have been linked to the deaths of American children.”

“This is a profound revelation,” Prasad wrote in the memo to staff members. “For the first time, the US FDA will acknowledge that Covid-19 vaccines have killed American children.”

He also wrote that new rules would impose tight restrictions on vaccines for pregnant women, marking another significant change in the agency’s approval framework.

“I remain open to vigorous discussions and debate,” Prasad wrote, reportedly adding that staff who did not agree with the core principles of his new approach should submit their resignations.

A PBS NewsHour correspondent first reported on the memo’s contents in a post on X. The New York Times noted that the document did not include identifying details such as the children’s ages, any existing health conditions, or how the causal relationship between vaccination and death was determined. The vaccine manufacturers involved were also not named.

Dr Paul Offit of Children’s Hospital of Philadelphia, who reviewed the memo, told MedPage Today that it’s a “dangerous and irresponsible thing to do”.

“[Prasad] says he has evidence that this vaccine killed 10 children, but that’s not the way it works,” Offit said. “If you think you have an extraordinary claim, you should back it up with extraordinary evidence. He should have submitted it to an excellent journal where it can be reviewed by subject matter experts who can say ‘Yes, this is clear evidence,’ then it can be published. That’s the way it works.”

Prasad’s predecessor, Dr Peter Marks, who led the FDA division throughout the pandemic, told the New York Times that he was taken aback by the “clearly political tone of the communication” and noted that the case reports of child deaths needed to be further investigated.

“I would not be surprised if the attributions turn out to be debatable, as these cases are often quite complex,” Marks told the Times after reading the memo.

Current and former FDA staff, as well as outside public health specialists, said the new plan could dramatically slow the vaccine pipeline, according to the Washington Post. Requiring far larger studies before granting approvals, they said, could delay product launches and make companies more cautious about developing or expanding vaccines and may discourage innovation in vaccine research.

Additionally, Prasad’s insistence on re-evaluating whether multiple vaccines should be given together could upend years of established federal guidance. The immunization schedule of the Centers for Disease Control and Prevention (CDC) currently recommends giving multiple childhood vaccines at the same medical visit. It also encourages adults to receive several shots for respiratory viruses, including the flu, Covid and RSV, during a single appointment for convenience.

Dr Kathryn Edwards, a vaccine expert and professor emeritus at Vanderbilt University in Nashville, Tennessee, told MedPage Today that the “determination of the cause of death in cases that are temporally related to vaccine administration is a very difficult task”.

“Saying definitively that a vaccine caused a death requires careful assessment, best done with an autopsy examination, and ruling out other causes of death,” she said. “That Covid vaccine might have caused a death related to myocarditis may indeed be the case. But [we] would need to see the details.”

Edwards added that such details would “best be presented in a peer reviewed manuscript where experts could review the details”.

“We also need to remember that Covid disease caused deaths [in kids], many more than 10,” she said. “I spent the entire pandemic reviewing cases of adverse events, I would be delighted to review these cases and assess the evidence that they have to say that they are vaccine caused.”

Prasad’s new framework reflects several themes long advanced by Kennedy and members of the anti-vaccine movement, who have pressed for additional proof of vaccine safety and effectiveness. In August, the FDA placed new restrictions on who can get Covid vaccines.

The agency authorized Covid vaccines for people 65 and older, who are known to be more at risk from serious illnesses from Covid infections. Younger people, though, were only considered to be eligible if they had an underlying medical condition that makes them particularly vulnerable.

In September, Kennedy’s vaccine panel that advises the CDC voted against recommending that people obtain a prescription for a Covid-19 vaccine, but added that coronavirus immunizations should be based on “individual-based decision making”.

Last week, it was reported that Ralph Abraham, a top Louisiana health official who stopped promoting mass vaccination policies and once described Covid-19 vaccines as “dangerous”, had been appointed as the new deputy director of the CDC.

Previous FDA leaders and independent scientists have emphasized that Covid-19 vaccines underwent extensive testing, including pediatric studies, and have been proven safe and effective. They argue that the benefits of vaccination far exceed the risks, which remain rare.