The US Centers for Disease Control and Prevention has been tracking abortion trends for decades, but this year’s report — including some of the earliest federal data reflecting the effect of significant changes to abortion access nationwide – has been pushed back until spring amid turmoil at the federal agency.

Global chikungunya outbreak prompts health warnings as cases surge across tropical regions. WHO reports 155 deaths from mosquito-transmitted virus.

Dr. Evelyn Griffin of Baton Rouge, a vaccine skeptic on the CDC panel that recommends immunization policy, has been named Louisiana surgeon general.

"What you have said is a terrible, terrible distortion of all the facts," one panel member

The CDC confirms a norovirus outbreak on an AIDAdiva cruise ship sickened 95 passengers and six crew members during a November voyage from Germany to multiple destinations.

Dr. Jessica Shepherd, chief medical officer for Hers, joins ABC News Live to discuss the flu season and flu vaccine.

Experts warn the decision could confuse doctors, burden families, and revive preventable infections as the committee reopens the entire childhood vaccine schedule.

Sen. Bill Cassidy urges the CDC to reject new hepatitis B vaccine guidance for newborns, calling the proposed change "a mistake."