Omicron: a more contagious but less dangerous variant? What the latest studies say

The Omicron variant is said to cause more infections but fewer hospitalizations than the Delta variant. Different scientific studies published in recent days seem to agree on this point of agreement. For example, in England, Imperial College London relied on 56,000 cases of Omicron and 269,000 cases of Delta detected between December 1 and 14 to come to this conclusion.

Study results suggest that individuals positive for the Omicron variant have, on average, a 20-25% reduced risk of going to hospital and an approximately 40-45% reduced risk of being hospitalized. resulting in an overnight stay or more, compared to those infected with the Delta variant. The average length of stay in hospital would also be shorter with an infection with the Omicron variant than with the Delta variant.

The Imperial College London study also tells us that reinfection with the Omicron variant is associated with an approximately 50 to 60% reduction in the risk of hospitalization, compared to a first infection. According to the researchers, the risk of contamination would also be higher with the Omicron variant, the latter being more transmissible and more resistant to vaccines, especially with only one or two doses.

“While the reduced risk of hospitalization with the Omicron variant is reassuring, the risk of infection remains extremely high. With the addition of the booster dose, vaccines continue to offer the best protection against infection and hospitalization”said Professor Azra Ghani of Imperial College London.

A study conducted by the University of Edinburgh in Scotland also looked at the severity of the Omicron variant and the effectiveness of vaccines in protecting against it. Based on hospital admissions, the results suggest that Omicron is associated with a two-thirds reduction in the risk of hospitalization for Covid-19 compared to Delta. Indeed, if the Omicron variant had an equivalent impact in terms of care, the researchers were counting on the hospitalization of 47 people when they were finally only December 15 to 19.

The same study suggests that the third dose / booster vaccination provides substantial additional protection against the risk of symptomatic Covid-19 for Omicron.

At the same time, a third study was carried out using data on contamination with the Omicron variant in South Africa. Its preliminary results indicate in particular that the risk of being hospitalized and / or of developing a severe form of the disease is 70 to 80% less when a person is infected with the Omicron variant compared to the Delta variant.

At the end of these three studies, the researchers also underline that the Omicron variant can still have a significant impact on hospital services due to its high contagiousness. “Due to the high transmissibility of the Omicron virus, it remains possible that healthcare services will face increasing pressure if cases of the Omicron variant continue to increase at the same rate as in recent weeks.”, reports Professor Neil Ferguson, director of the Center for Global Analysis of Infectious Diseases at Imperial College London.

“An individual infection could be relatively mild for the vast majority of people, but the potential for all of these infections to occur at once and put serious pressure on the NHS (Editor’s note: National Health Service: the health system in the United Kingdom) remains”, also affirms, in the same direction, the professor Mark Woolhouse, of the University of Edinburgh.