Conclusions to be confirmed. Two studies carried out in Great Britain and published on Wednesday show that infections with the Omicron variant of Covid-19 are less likely to cause hospitalizations compared to the Delta variant, confirming a trend first observed in South Africa.
These preliminary studies – one from Scotland, the other from England – were welcomed by experts, who were however cautious and pointed out that the high transmission rate of the variant could still result in more disease. severe cases.
Scottish research looked at the cases recorded in November and December, and grouped them into two groups: Delta on one side, Omicron on the other.
According to this study, “Omicron is associated with a two-thirds reduction in the risk of hospitalization for Covid-19 compared to Delta”. It has also been shown that a booster dose provides substantial additional protection against symptomatic infection. This is a small study that did not look at anyone hospitalized and under the age of 60, but the authors said they adjusted for those limits using statistical methods.
In attention of a peer review
The second study, from England, found a 20-25% reduction in any type of hospitalization for Omicron compared to Delta, and a 40-45% reduction in overnight stays (“ admissions ”).
The Scottish study only looked at admissions. “While the reduction in the risk of hospitalization with the Omicron variant is reassuring, the risk of infection remains extremely high,” warned Azra Ghani of Imperial College London, who co-authored the English study. “By adding the booster dose, vaccines continue to offer the best protection against infection and hospitalization.”
Neither study has yet been peer reviewed, but they add to a growing body of evidence about Omicron. It is not clear if the decrease in the rate of severe cases seen with Omicron is due to the characteristics of the variant or if it appears less severe because it encounters populations with more immunity because of being vaccinated or having been ill with Covid. in the past.