This week has been an eventful one for America's public health agency. Two former leaders of the US Centers for Disease Control and Prevention explained why they suddenly departed in a Senate hearing. They also described how CDC employees are being instructed to turn their backs on scientific evidence. They painted a picture of a health agency in turmoil--and at risk of harming the people it is meant to serve. And, just hours afterwards, a panel of CDC advisers voted to stop recommending the MMRV vaccine for children under four. This article first appeared in The Checkup, MIT Technology Review's weekly biotech newsletter.

The vaccine advisory group ACIP, not all members of which seemed to know what the group does, recommended to the CDC that combined MMRV shots not be given before age 4. A federal vaccine advisory committee made of members hand-picked by Health and Human Services Secretary Robert F. Kennedy Jr. recommended in an 8-3 vote on Thursday that the combined measles, mumps, rubella and varicella (MMRV) vaccine should not be given before age four, citing long-known evidence that shows a slightly increased risk for febrile seizures in that age group. Experts say that while frightening, febrile seizures--which are uncommon after vaccination--are usually short-lived and harmless, and removing the option for parents could cause a decline in immunization rates against measles, mumps, and rubella, some of the most dangerous childhood diseases. Known as the Advisory Committee on Immunization Practices, or ACIP, the group provides recommendations to the US Centers for Disease Control and Prevention on vaccine usage. These recommendations are typically adopted by CDC and have an impact on state vaccine requirements for school, insurance coverage of vaccines, and pharmacy access--something at least one member of the panel seemed to be unaware of. Thursday's vote is part of a new shift in vaccine policy being spearheaded by Kennedy, a longtime anti-vaccine activist.