CDC: Boosters Key in Protecting Against Omicron

Lindsay Kalter

December 13, 2021

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Most of the 43 cases of the COVID-19 Omicron variant found in the United States were mild and occurred among vaccinated people, but boosters are effective against it, according to a report the CDC released Friday.

Of the 43 people with cases, more than half were 19 to 39 years old, and 34 had been fully vaccinated. But only nine people had received a booster shot at least 2 weeks prior to becoming infected.

A total of 14 people with Omicron had reported traveling internationally, and six had been previously infected with COVID-19.

"In reported cases thus far, most people experienced only mild symptoms, which is what we would expect from a group of fully vaccinated individuals," CDC Director Rochelle Walensky, MD, said at a White House COVID-19 Response Team news briefing Friday. "Although we don't have all the answers on the Omicron variant, initial data suggest COVID-19 boosters help bolster protection against Omicron."

The Omicron variant has been found in 25 states.

Walensky pointed to two recent studies from Israel, published in TheNew England Journal of Medicine, that examined how well booster shots worked. One study found that for those over the age of 50, boosters resulted in a 90% decrease in mortality from the Delta variant, compared to people with only two doses. Another study found a 20-fold decrease in severe disease across all age groups in those who had received their booster shots, compared to those with two doses.

The CDC expanded recommendations for boosters Thursday for young adults 16 and 17 years old, as COVID-19 cases continue to rise.

Walensky reported a 7-day average of 118,500 cases per day -- an increase of 37% from the previous week. Hospitalizations for COVID-19 have increased by 16% to 7,400, and daily deaths are up 28% to 1,100.

Walensky encouraged people to vaccinate their children and included a reminder that Delta is still the dominant variant in the United States, accounting for 99% of COVID-19 cases.

So far, more than 50 million booster doses have been given in the U.S., and 7 million children ages 5-11 have been vaccinated.

"As a mother of three, I know the concerns that parents hold for the health and safety of their children," Walensky said. "These vaccines are not only safe, but they're highly effective in preventing severe disease, hospitalization, and death."


News briefing, White House COVID-19 Response Team, Dec. 10, 2021.


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