Updated booster shots have strengthened Americans’ defenses against severe Covid, reducing the risk of hospitalization by about 50 percent compared to certain groups inoculated with the original vaccines, the Centers for Disease Control and Prevention reported of Diseases in a pair of studies published Friday.
The research represents the agency’s first look at how the reformulated boosters, designed to protect against recent variants of Omicron, work in preventing serious consequences of infection with the virus, including visits to the emergencies and hospitalizations.
Federal health officials are urging Americans to get updated booster shots, hoping to revive a delayed vaccination campaign. So far, however, fewer than a fifth of American adults and only a third of those 65 and older have received updated vaccines, reflecting a retreat in many parts of the country from earlier, more aggressive vaccination pushes in the pandemic
New virus variants that are better able to evade the immune system have gained traction, and Covid cases and hospitalizations have increased in recent weeks. About 375 Americans die each day on average, a 50 percent increase over the past two weeks. The elderly have been particularly affected.
The virus has compounded the difficulties facing a healthcare system already under strain from the resurgence of influenza and respiratory syncytial virus after two years of reductions in these infections.
Read more about the coronavirus pandemic
- Free home tests: With cases on the rise, the Biden administration restarted a program that has provided hundreds of millions of tests through the Postal Service.
- Updated features: The Food and Drug Administration expanded eligibility for updated coronavirus boosters to children as young as 6 months.
- Contagion: Like a zombie in a horror movie, the coronavirus can persist in the bodies of infected patients long after death, even spreading to others, according to two surprising studies.
- Pregnant woman: Although studies have shown that the Covid vaccine is safe for pregnant women, many have avoided vaccination, not knowing the risks posed by the virus.
While federal health officials encourage testing and the use of masks in certain settings, the precautions have become far less common in practice. Antiviral drugs for Covid remain difficult to find for many who are infected.
“We probably won’t see waves of Covid like we’ve seen in the past, which is a good thing, but it doesn’t mean people aren’t still dying and those lives couldn’t still be saved if we get more shots at guns.” , said Dr. David Dowdy, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health.
A CDC study released Friday examined how the updated traits protected people from emergency department visits and Covid-related hospitalizations at seven health systems.
The study, which looked at about 15,000 hospitalizations, spanned from mid-September to mid-November, when the Covid cases were largely caused by the BA.5 Omicron variant, the target, in part, of the reformulated features.
Since then, however, more evasive versions of Omicron known as BQ.1 and BQ.1.1 have become more common, and the relevance of the findings to newer variants is unclear.
During the BA.5 period, people who had received the updated boosters had a 57% lower risk of hospitalization compared to unvaccinated people, a 38% lower risk compared to people who had recently received doses of the original vaccine and 45% less. Risk compared with people whose last dose of the original vaccine was at least 11 months earlier.
But the CDC study did not take into account whether patients had been previously infected with the virus, which could make the updated vaccines appear less effective than they are. And the research didn’t take into account whether certain groups were more likely to have received treatments like Paxlovid, which could have skewed the results.
A second study reported on the benefits of updated boosters for older Americans in 22 hospitals from early September to late November.
Among people aged 65 and older, the updated vaccines reduced the risk of hospitalization for Covid by 84% compared with unvaccinated people and by 73% compared with people who had received at least two doses of the original vaccines
CDC scientists said higher estimates of vaccine effectiveness in older age groups could reflect a variety of differences in the particular groups of patients being studied.