Younger Americans benefited less from boosters than older people

The figures confirm that booster doses are most beneficial to older adults, as the C.D.C. has previously reported. But the new numbers for younger Americans were less compelling. In those age groups, vaccination itself — two doses of the Moderna or Pfizer-BioNTech vaccines, or one dose of the Johnson & Johnson vaccine — decreased the risk of hospitalization and death so sharply that a booster shot did not seem to add much benefit.

The data run only through the end of December, when the Omicron surge had just begun. Because the variant is so highly contagious, booster shots may have helped limit the variant’s spread through the population, an argument for boosters that would not be fully captured in the new research…

“I do not think these data support a universal booster rollout for everyone,” said Dr. Celine Gounder, an infectious disease expert and epidemiologist at Kaiser Health News.