COVID-19: omicron hospitalization less likely, two British studies show

The omicron variant of the coronavirus COVID-19 it could be less severe than the delta version, according to preliminary evidence from two new British studies.

The scientists stress that even if the findings of those initial studies are confirmed, any decrease in severity must be weighed against the fact that omicron spreads much faster than delta and has a greater ability to evade the protection generated by vaccines. In fact, the large numbers of those infected could still overwhelm hospitals.

However, new studies released Wednesday appear to bolster initial research suggesting omicron may not be as dangerous as the delta variant, said Manuel Ascano Jr., a Vanderbilt University biochemist who studies viruses.

“Cautious optimism is perhaps the best way to look at this,” he noted.

According to an analysis by the COVID-19 response team at Imperial College London on the risks of hospitalization for omicron cases in England, people infected with omicron are 20% less likely to go to hospital than with the delta variant, and 40% less likely to be hospitalized for one night or more.

The analysis included all cases of COVID-19 confirmed by PCR tests in England in the first half of December in which the variant could be identified: 56,000 cases of omicron and 269,000 of delta.

A separate study conducted in Scotland by scientists at the University of Edinburgh and other experts found that the risk of hospitalization was two-thirds lower with omicron than with delta.

But that study pointed out that the nearly 24,000 omicron cases in Scotland were predominantly in adults between the ages of 20 and 39. Young people are less likely to develop severe cases of COVID-19.

“This national investigation is one of the first to show that omicron is less likely to result in a COVID-19 hospitalization than with delta,” the researchers wrote. Although the conclusions are initial observations, “they are encouraging,” they added.

The findings have not yet been reviewed by other experts, the gold standard in scientific research.

Ascano noted that the studies have limitations. For example, the findings are specific to a certain point in time during a rapidly changing situation in Great Britain, and in other countries it might be different.

Matthew Binnicker, director of clinical virology at the Mayo Clinic in Rochester, Minnesota, said that in the Scottish study, the percentage of young people was almost double in the omicron group compared to the delta group, and that “could have biased the conclusions. of the results on the least severity of omicron ”.

However, he noted that the information was interesting and suggests that omicron could cause a less severe illness. But he added: “It is important to emphasize that if omicron has a much higher rate of transmission compared to delta, the absolute number of people needing hospitalization could still increase, despite less severe disease in most cases.”

Information from South Africa, where the variant was first detected, also indicates that omicron may be less severe there. Salim Abdool Karim, a clinical epidemiologist of infectious diseases in South Africa, said this week that the hospitalization rate was much lower with omicron cases than with delta cases.

“Our overall hospitalization rate is around 2% to 4% compared to before, when it was almost 20%,” he said. “So even though we are registering a lot of cases, there are few hospitalizations.”