People infected with Omicron were half the risk of being hospitalized than those with Delta, according to the work. The risk of being placed in intensive care was reduced by regarding 75%, and the risk of dying by more than 90%.
Of the more than 52,000 people infected with Omicron followed by this study, none needed a life support, compared to 11 of the nearly 17,000 infected with Delta.
In addition, the median length of hospitalization was 1.5 days for Omicron, compared to nearly 5 days for Delta.
This analysis was conducted using data from the California hospital system of Kaiser Permanente, during the month of December 2021, when both variants were circulating widely.
These data reinforce those accumulated from populations in other countries, for example in South Africa or Great Britain. But also those having shown – in animals or ex vivo (outside the human body) – that Omicron replicates more in the upper airways (nose, throat) than in the lungs, where serious forms of Covid start. -19.
The study, which has yet to be peer-reviewed, was conducted by researchers at the University of California, Berkeley, Kaiser Permanente, and the Centers for Disease Prevention and Control (CDC).
“The study took into account important parameters such as age, gender, past SARS-CoV-2 infections, vaccination status and comorbidities,” Rochelle Walensky, CDC director, said on Wednesday, citing this study at length during a press conference.
The results show that Omicron is “inherently less serious” than Delta, and not only that people who are more immune (following a past infection or a vaccine) are now catching it, the study explains.
In addition, if this work noted a reduced effectiveness of the vaccines once morest infections linked to Omicron, the protection remained nonetheless substantial once morest the serious forms of the disease.
Despite everything, Ms. Walensky pointed out that Omicron’s very high contagiousness automatically led to a large number of hospitalizations, putting pressure on a care system whose staff had already been strained for two years.
The country currently records an average of 750,000 new cases per day, and regarding 1,600 deaths daily.
More than 150,000 people are currently hospitalized with Covid-19 in the United States, a record.
