The U.S. Centers for Disease Control and Prevention said on November 29 everyone aged 18 years and older should get a booster shot, as the CDC looks to tackle a new and highly infectious strain of the coronavirus that is quickly spreading across the globe.

Millions of Americans got COVID-19 booster shots at a near record pace after the Biden administration expanded eligibility last week, but health officials concerned about climbing infections ahead of the winter holiday season urged more to get the additional protection.

The U.S. Food and Drug Administration approved Covid-19 vaccine booster shots for all Americans ages 18 and over Friday morning.  

Moderna Inc. said on November 17 the company had applied with the U.S. Food and Drug Administration for authorization of the Covid-19 booster vaccine for all adults aged 18 and older.

The U.S. Food and Drug Administration said on November 16 it would review Pfizer Inc.’s request to authorize booster doses of the company’s Covid-19 vaccine in all adults “as expeditiously as possible,” with the New York Times reporting that the regulatory nod could come as soon as November 18.

Pfizer Inc. and BioNTech SE on November 9 requested the U.S. Food and Drug Administration to authorize booster doses of their Covid-19 vaccine in all adults, presenting recent data showing the shot would help prevent disease across ages.

In the face of Delta, the actual efficacy of Covid-19 vaccines in a real-world setting has come into question even if they still appear to be very close to 100 percent at preventing death or severe disease, which is the primary goal of a vaccine. Studies suggest that Moderna’s Covid-19 vaccine appears better than the Pfizer-BioNTech vaccination in terms of antibody count and prevention of hospitalizations, and both were significantly more effective than Johnson & Johnson’s shot.

The Centers for Disease Control and Prevention gave the go-ahead for the use of Moderna’s and Janssen’s Covid-19 vaccines as booster shots six months and two months, respectively, after their initial series as well as the approval of mixing and matching vaccines. 

Americans can choose a Covid-19 booster shot that is different from their original inoculation but the recommendation is to stick with the vaccine they got first if available, White House chief medical adviser Dr. Anthony Fauci said on Oct. 22.

A booster dose of the Covid-19 vaccine developed by Pfizer Inc. and German partner BioNTech SE restored efficacy to 95.6 percent against the virus, including the Delta variant, data released by the companies from a large study showed on Oct. 21.