Covid-19: new data indicate omicron is less severe, but alert remains

The wave of infections with the omicron variant of the coronavirus appears to be milder, according to recent and preliminary studies published in the United Kingdom and South Africa.

Initial evidence suggests that fewer infected people are needing to be hospitalized compared to other variants. Estimates range from a 30% to 70% reduction in the need for hospitalization.

Still, there remains concern that a large number of infections will end up overwhelming hospitals.

In the UK, more than 100,000 Covid-19 cases were registered in a single day for the first time.

A preliminary study by the University of Edinburgh, Scotland, has been precisely tracking the number of infected people who end up needing the hospital. According to the researchers, if the omicron behaved in the same way as the delta variant, 47 people would be expected to have already been hospitalized in Scotland, but so far, there are only 15 patients in this situation. These results were published on Wednesday (22) and have not yet gone through the so-called peer review.

However, the study suggested that the course of the disease among the few patients who were hospitalized with omicron was the same as among patients infected with other variants.

“Convincingly, our data together suggest a positive finding of reduced severity in omicron compared to other variants,” said Cheryl Cohen of the National Institute of Communicable Diseases in South Africa.

more protected population

The reduction in severity is believed to be the result of a combination of fundamental omicron characteristics and high levels of immunity in the population due to vaccination and past infections.

An analysis of omicron published by Imperial College London on Wednesday suggests that mutations in this variant made it milder than delta.

The authors of the analysis stated that the chances of an infected person needing emergency care are 11% lower with omicron than with delta, in cases of people without prior immunity.

But in the UK, this data turns out to apply to relatively few people due to the high levels of vaccination and previous infection in the country.

Considering the much larger group of people with some degree of immunity, the propensity to need emergency care is 25% to 30% lower with omicron; and the propensity for hospitalization for more than one day is reduced by 40% with this variant.

One of the authors of the review, Professor Neil Ferguson, said that this “is clearly good news, to some extent.”

He warned that these reductions were not enough “to drastically change” the speed at which the omicron is spreading and that “there is the potential that there are still a number of hospitalizations that could put the health system in a difficult position.”

Peter Openshaw, also of Imperial College but not involved in the study, argued that all of these recent preliminary publications cannot be interpreted as if the omicron had turned Covid-19 into “a common cold.”

“That would be a misinterpretation,” says Openshaw.

Some laboratory studies have suggested possible reasons for the omicron to be milder.

The University of Hong Kong has shown that the variant is effective at infecting the airways, but not so much at entering the deep tissues of the lungs, which would cause more damage.

Cambridge University also found that the variant is not as good at fusing together lung cells, which happens in the lungs of people who become seriously ill.