All adults should get Covid-19 booster shots when they're eligible, the Centers for Disease Control and Prevention said Monday, striking a much stronger tone than its recommendations just a few weeks ago.
The new advice was issued days after the new omicron variant of the coronavirus was detected in southern Africa. The variant's constellation of mutations suggests the virus could evade the immune system or spread more easily than previous variants do, although it will take time to determine its impact.
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"Everyone ages 18 and older should get a booster shot ... when they are 6 months after their initial Pfizer or Moderna series," the CDC's director, Dr. Rochelle Walensky, said in a statement. Anyone who got the single-dose Johnson & Johnson vaccine shot at least two months ago would also qualify.
The CDC only earlier this month recommended that people ages 50 and up, as well as those in long-term care facilities, should get a booster. The agency said at the time adults ages 18 to 49 may choose to get a booster, based on their risk.
The emergence of the omicron variant has changed the advice, broadening the "should" recommendation to all adults.
As "scientists in the United States and around the world are urgently examining vaccine effectiveness related to this variant," Walensky said, "I strongly encourage the 47 million adults who are not yet vaccinated to get vaccinated as soon as possible and to vaccinate the children and teens in their families as well because strong immunity will likely prevent serious illness."
In addition to vaccines, Walensky and other experts said, tried-and-true prevention strategies continue to be effective, such as masking, more testing and physical distancing.
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