“There's no reason to vaccinate a newborn for hepatitis B [and the first dose should be delayed until age 12].”

Trump's premise is false: hepatitis B is not only sexually transmitted. The virus is bloodborne, and babies can contract it from an infected mother during birth, which is precisely why the CDC recommends a birth dose. Although pregnant people are routinely tested, some are missed and tests can err, so the newborn dose acts as a critical safety net to prevent infection in every child.

Delaying the vaccine to age 12 would leave children exposed during the years they are most vulnerable to lifelong harm. The earlier in life a person contracts hepatitis B, the more likely the infection becomes chronic, which can lead to cirrhosis, liver cancer, or liver failure. Infants who acquire the virus face up to a 90 percent risk of developing chronic infection, compared with a far smaller share of adults.

Young children can also catch hepatitis B from infected caregivers who don't know they carry it, through shared food, toothbrushes, or washcloths, because very small amounts of blood spread the virus. Even RFK Jr.'s hand-picked CDC vaccine advisory committee stopped well short of Trump's advice. In December 2025, after his remarks, it dropped the universal birth-dose recommendation for infants of mothers who test negative, moving to individual decision-making with the first dose no earlier than 2 months if not given at birth; it made no recommendation to wait until age 12, and it kept the birth dose for infants of mothers who test positive or whose status is unknown. The American Academy of Pediatrics warns that delaying vaccines means "children will not have immunity against these diseases at times when they are most at risk."

"Pediatricians know firsthand that children's immune systems perform better after vaccination against serious, contagious diseases like polio, measles, whooping cough and Hepatitis B. Spacing out or delaying vaccines means children will not have immunity against these diseases at times when they are most at risk." — Dr. Susan Kressly, President, American Academy of Pediatrics