NEW YORK (NYTIMES) The Centres for Disease Control and Prevention (CDC) on Thursday (Feb 3) night published new data on the risks of hospitalisation and death from Covid-19 among people who are unvaccinated and vaccinated, with or without booster doses.
The agency recommends booster shots for Americans 12 and older.
This is the first comprehensive data on the effectiveness of boosters by age in the United States.
The figures confirm that booster doses are most beneficial to older adults, as the CDC 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 vaccines, or one dose of the Johnson & Johnson vaccine – decreased the risk of hospitalisation and death so sharply that a booster shot did not seem to add much benefit.
The data runs 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.
Still, several recent studies have found that vaccination alone, without boosters, remained strongly protective against severe illness and death in most people, even after Omicron’s appearance.
“I do not think these data support a universal booster rollout for everyone,” said Dr Celine Gounder, an infectious disease expert and public health researcher at Kaiser Health News.
Instead, boosters seem most essential for older adults, she said, and those who have certain immune conditions or live in long-term care facilities.
In younger Americans, it may have made sense to make booster shots available only to those with certain medical risks, she said.
The advantages of booster shots in various age groups were hotly debated in the fall, when the Delta variant was the primary form of the virus in the US. But many scientists came to favour additional doses after the arrival of the highly contagious Omicron variant.
“The effect of the booster can be seen in the datasets, but it’s far smaller than the effect of vaccination compared to not,” said Professor John Moore, a virus expert at Weill Cornell Medicine in New York.
“The real problem is the carnage among the unvaccinated.”
Unvaccinated people in every age group are at higher risk of infection, hospitalisation and death than those who have been immunised, according to the CDC’s data – a persistent trend since vaccines were introduced.
