States are bracing for confusion as the Biden administration begins rolling out booster doses of Pfizer's COVID-19 vaccine.

Chaotic and at times disparate messaging from administration health officials over the past month has culminated in a complicated set of recommendations about who should be getting booster shots, and why.

But in a decision announced after midnight on Friday morning, CDC Director Rochelle WalenskyRochelle WalenskySunday shows preview: Pelosi announces date for infrastructure vote; administration defends immigration policies Israel says US booster decision vindicates its vaccine strategy Overnight Health Care — Presented by Indivior — Walensky gives green light for boosters MORE broke with the advisory committee and signed off on a broader policy.

Experts said Walensky's decision will make boosters available for health care workers, teachers, grocery store workers and other frontline workers.

If we are going to create guidelines that are essentially making the vaccine available to almost everyone, the simplest solution is, make it available to everyone," said Celine Gounder, an infectious disease specialist and epidemiologist at NYU and Bellevue Hospital.

But if the goal of a booster shot is mainly to allay fears and anxieties among frontline workers, Gounder said, "there just isn't data to back that a young healthy health care worker is actually at risk.".

Last month, Biden and top health officials, including Acting Food and Drug Administration (FDA) Commissioner Janet Woodcock, Walensky and Surgeon General Vivek MurthyVivek MurthyCDC director partially overrules panel, signs off on boosters CDC panel authorizes COVID-19 vaccine boosters for high-risk people, those over 65 FDA authorizes Pfizer COVID-19 booster shot for older and high-risk Americans MORE announced that a booster shot program for all adults would begin the week of Sept.

Marcus Plescia, chief medical officer of the Association of State and Territorial Health Officials, said states are not expecting additional clarity from the federal government.

While there's no evidence about mixing a third Pfizer dose with two doses of the Moderna vaccine or a single dose of the Johnson & Johnson shot, Plescia said state health officials will have a difficult time conveying that to members of the public clamoring for boosters.