Coronavirus boosters cut hospitalization risk by at least 50%, CDC data shows

Adults who received the updated coronavirus booster shots are better protected against severe disease than those who haven’t, cutting their risk of having to visit an emergency room or being hospitalized with covid-19 by 50 percent or more, according to new federal data.

Two reports released Friday by the Centers for Disease Control and Prevention give the first detailed look at how well the updated boosters from Pfizer and Moderna protect against serious illness. But uptake of the “bivalent” boosters rolled out in September has been low among vaccine-weary Americans, with only about 14 percent of those eligible — ages 5 and older — having received an updated shot.

Administration officials are renewing a push for more Americans to get the latest shots in anticipation of another covid-19 winter surge coming on top of an early and aggressive influenza season and high levels of respiratory syncytial virus (RSV). The triple whammy of viruses is straining hospitals, keeping families sick for weeks, and forcing parents to miss work in record numbers.

At this time last year, there were twice as many covid-19 cases and about 70,000 people hospitalized, with deaths averaging about 1,300 a day. (Case data is a much less-reliable indicator now because at-home test results go unreported.)

Jeanne Marrazzo, director of infectious diseases at the University of Alabama at Birmingham, said the new CDC data on booster effectiveness is encouraging.

“Pretty amazing that both studies could show a significant (and in older adults, quite substantial!) effect so quickly, given that the vaccine wasn’t even available till Sept. 1,” she wrote in an email.

Marrazzo’s takeaway: “In this winter of respiratory viruses run amok, the best thing people can do (especially older adults) is to get the bivalent booster and influenza vaccine (data indicate it’s pretty well matched with circulating strains this year)!”

CDC data last month showed that Americans who had received the updated boosters had better protection against symptomatic coronavirus infection than those who had not. The latest reports provided more granular detail and showed the boosters offer “an even bigger benefit,” especially for adults who received their last vaccine shot almost a year ago, said Ruth Link-Gelles, leader of the CDC’s coronavirus vaccine effectiveness team.