COVID vaccination is highly protective against severe omicron-related disease, according to the latest study of hospitalizations by the Centers for Disease Control and Prevention. But long-term care facility residents continue to face greater risks than the general population, even when they’ve had the shots, its investigators have found. 

The researchers looked at rates of adults hospitalized with COVID-19 in the United States between January and April 2022, when the omicron variant was responsible for most SARS-CoV-2 infections. When compared to patients who had been vaccinated and received booster doses, hospitalization rates were 10.5 times higher in the unvaccinated and 2.5 times higher in those who were vaccinated with no booster doses. 

Age, fragility and vaccination

A greater proportion of patients who were hospitalized despite being vaccinated were older — with a median age of 70 vs. 58 — when compared to unvaccinated patients. These patients were more likely to be medically fragile and to reside in long-term care facilities, the investigators also found. In addition, hospitalized, vaccinated patients had greater odds of having three or more underlying medical conditions, including immunosuppression (78% vs. 52%).

What’s more, although vaccinated patients had shorter lengths of hospital stays than unvaccinated patients, there was “no clear difference” between rates of intensive care unit admission and in-hospital death between the two groups of patients after adjusting for confounding factors. 

Baseline vulnerability

The latter finding likely reflects that vaccinated, hospitalized adults were initially more vulnerable to severe infection than those who are unvaccinated, the researchers concluded.

The results underscore the strong link between vaccination and protection against severe COVID-19 illness, “a salient finding when many eligible Americans remained unvaccinated,” the researchers contended.

Clinicians, take note

In data from April 2022, fewer hospitalized patients aged 65 years or older were vaccinated than were unvaccinated, which is to be expected, investigators noted. But the relatively high proportion of hospitalized patients who were vaccinated signals that clinicians should take additional protective measures on top of encouraging vaccination, they wrote.

This includes the increased use of early outpatient antiviral treatment for patients at high risk of severe COVID-19, “regardless of vaccination status,” they said. 

Preexposure prophylaxis with the monoclonal antibody tixagevimab and cilgavimab (Evusheld) was recommended for immunocompromised patients.

The study was published in JAMA Internal Medicine.

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