A large American study, carried out on nearly 70,000 people who tested positive for Covid-19, reassures somewhat and confirms what several studies have already found around the world.
Study after study, the trend seems to be confirmed, and that’s good news. American researchers have studied the case of 70,000 people who tested positive for Covid-19. Their results confirm what the scientific community foresaw: the risk of hospitalization and death is substantially reduced with the Omicron variant compared to Delta, regardless of the increasing levels of immunity within the population.
People infected with Omicron were half as likely to be hospitalized as those with Delta, according to this work. The risk of being placed in intensive care was reduced by around 75%, and that of dying by more than 90%. Of the more than 52,000 people infected with Omicron followed by this study, none required life support, compared with 11 of the nearly 17,000 infected with Delta. Additionally, the median length of hospital stay was 1.5 days for Omicron, compared to nearly 5 days for Delta.
Upper airways
This analysis was conducted using data from the Kaiser Permanente California hospital system, during the month of December 2021, when the two variants were circulating widely. These data reinforce those accumulated with the populations of 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 the severe forms of Covid-19 start. .
The study, which has not yet been peer-reviewed, was conducted by researchers from the University of California, Berkeley, Kaiser Permanente and the Centers for Disease Control and Prevention (CDC). “The study took into account important parameters such as age, sex, past Sars-CoV-2 infections, vaccination status and comorbidities,” CDC director Rochelle Walensky said Wednesday, citing this study at length during a press conference.
” Less severe “
The results thus show that Omicron is “inherently less serious” than Delta, and not only that people with more immunity (after a past infection or a vaccine) currently catch it, explains the study. Moreover, although this work noted reduced efficacy of the vaccines against infections linked to Omicron, the protection nevertheless remained substantial against the severe forms of the disease.
Despite everything, Rochelle Walensky pointed out that the very high contagiousness of Omicron mechanically led to a large number of hospitalizations, putting pressure on a healthcare system whose staff have already been put to the test for two years. The country is currently registering an average of 750,000 new cases per day, and about 1,600 deaths daily. More than 150,000 people are currently hospitalized with Covid-19 in the United States, a record.