U.S. Backs Boosters for All in Bid to Blunt Virus Resurgence

Millions more Americans can now receive Covid-19 booster shots from Pfizer Inc. and Moderna Inc., after U.S. officials broadened what many state and local leaders and health-care providers had said were confusing initial eligibility guidelines.

Centers for Disease Control and Prevention Director Rochelle Walensky on Friday signed off on guidance that makes boosters available to all adults 18 and up who received a second dose of one of the messenger RNA vaccines at least six months earlier.

Walensky said in a statement that boosters are “an important public health tool to strengthen our defenses against the virus as we ...