It “should be clear” that both birth vaccination schedules – with or without hepatitis B – are not “dangerous to anyone”, he wrote. There is a clear benefit to giving hepatitis B vaccines at birth, and not doing so can lead to lifelong danger, experts say.

Conducting a study like this “makes the case that there’s something that’s worthy of study, for which they have no evidence”, Offit said.

“We have millions and millions, arguably hundreds of millions, of children in this world who have gotten that vaccine as a birth dose or haven’t. If there was any evidence that this was problematic, you would know this by now,” Offit added. “We eliminated hepatitis B in the United States in children virtually within years of starting that program, so the benefits are clear.”