New Covid booster shots halve risk of hospitalization, CDC reports

The updated booster shots have strengthened Americans’ defenses against severe Covid, reducing the risk of hospitalization by about 50% compared to some groups inoculated with the original vaccines, the Centers for Disease Control and Prevention reported in a pair of studies published Friday.

The research represents the agency’s first look at how reformulated boosters, tailored to protect against recent Omicron variants, work in preventing serious consequences of virus infection, including ward visits emergencies and hospitalizations.

Federal health officials are urging Americans to get the updated booster shots, hoping to revive an overdue vaccination campaign. So far, however, less than a fifth of American adults and only a third of people aged 65 and over have received updated vaccines, reflecting a setback in many parts of the country from vaccination campaigns. more aggressive at the start of 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, an increase of 50% over the past two weeks. The elderly have been particularly affected.

The virus has exacerbated the difficulties facing a health system already strained by resurgences of influenza and respiratory syncytial virus after two years of reductions in these infections.

Even though federal health officials are encouraging testing and the use of masks in some settings, precautions have become much less common in practice. Antiviral drugs for Covid remain difficult to obtain for many infected people.

“We probably won’t see waves of Covid like we’ve had in the past, which is a good thing, but that doesn’t mean people still aren’t dying and those lives still couldn’t be saved if we were getting more gunshots,” said Dr. David Dowdy, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health.

A CDC study released Friday examined how updated plans protected people from Covid-related emergency department visits and hospitalizations in seven health systems.

The study, which looked at around 15,000 hospitalizations, spanned from mid-September to mid-November, when Covid cases were largely caused by the BA.5 Omicron variant – the target, in part, reformulated injections.

Since then, however, more elusive 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 period BA.5, 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 a 45% lower risk compared to people whose last dose of the original vaccine was at least 11 months old.

But the CDC study did not take into account that patients had already been infected with the virus, which could make updated vaccines 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 benefits of updated reminders for older Americans at 22 hospitals from early September to late November.

Among people aged 65 and over, updated vaccines reduced the risk of Covid hospitalization by 84% compared to unvaccinated people, and by 73% compared to people who had received at least two doses of the original vaccines.

The CDC scientists said the higher estimates of vaccine effectiveness in older age groups could reflect a variety of differences in the particular groups of patients studied.