A Moderna or Pfizer/BioNTech COVID-19 booster dose was found to give highly effective protection against the Delta and Omicron variants, the Centers of Disease Control and Prevention (CDC) said Friday.

A third dose of the messenger RNA (mRNA)-based vaccines reduced COVID-19-linked emergency department and urgent care visits by 94 percent for Delta strain cases, and by 82 percent for Omicron strain cases, according to the real-world findings.

The boosters were also effective at preventing COVID-19-associated hospitalizations by 94 percent for Delta and by 90 percent for Omicron.

The data were gathered from 222,772 emergency department and urgent care visits and 87,904 hospitalizations across 10 U.S. states from August 2021 to January 2022, a time marked by the prevalence of Delta and the rise of Omicron.

The findings support recent studies suggesting that a third dose of the Pfizer/BioNTech or Moderna vaccine induces greater immunity than simply a primary two-dose vaccination series (DID, Dec. 9, 2021).

In January, the CDC updated its recommendation for when individuals may receive an mRNA booster shot following a primary vaccination series, reducing the postvaccination period from six months to five months for a booster. — Jason Scott