U.S. health authorities have advised COVID-19 booster shots for all adults 18 and older.
According to CNN, Centers for Disease Control and Prevention Director Rochelle Walensky endorsed the third shot on Friday, just hours after CDC advisers voted unanimously to recommend booster doses of Pfizer and Moderna vaccines for all adults six months after they completed their two-dose regimen.
The recommendation simplifies previous, complicated guidance for boosters that were different according to age, health status and occupation.
Janssen vaccine recipients can get boosters two months after their primary jab.
The booster roll-out is expected to begin on Saturday in the U.S., though some states and cities have already allowed third doses for all adults even before this latest guidance was issued.
Walensky said the unanimous decision carefully considered the current state of the pandemic, vaccine effectiveness data over time and review of safety data.
She said booster shots have demonstrated the ability to safely increase people's protection against infection and severe outcomes. She said they are an important public health tool to strengthen defense against the virus as the winter holiday season arrives.