Covid is less severe with Omicron than Delta, US study suggests

The Omicron variant appears to result in less severe Covid-19 than seen during previous periods of high coronavirus transmission including the Delta wave, with shorter hospital stays, less need for intensive care and fewer deaths, according to a new US study.

However, the fast-spreading Omicron variant has led to record numbers of infections and hospitalizations, straining the US healthcare system.

Despite the steep spike in Covid cases, the percentage of hospitalized patients admitted to intensive care units (ICU) during the current Omicron wave was about 29% lower than during last winter's surge and some 26% lower than during the Delta wave, the study published on Tuesday in the US Centers for Disease Control and Prevention's (CDC) Morbidity and Mortality Weekly Report found.

The lower Covid-19 disease severity during the Omicron period is likely related to higher vaccination coverage, booster use among those eligible for the extra shots, as well as prior infections providing some immune protection, the study said.