A Hepatitis B vaccine in Atlanta, Georgia, September 29, 2023. The CDC vaccine advisory committee, called ACIP, is also weighing new restrictions on existing recommendations for the combined MMRV shot to protect against measles, mumps, rubella and chickenpox. From there, the vote will need signoff from the acting CDC director or the Health and Human Services secretary. “I can promise you there will be some hepatitis B transmission,” Cassidy told reporters when asked what would happen if the committee makes changes to already-existing recommendations. The upcoming vote Thursday only discusses the first dose, and parents would still have a choice about their preference for the second shot in older children.