It is now “Omicron dominance on a global scale”. This is sanctioned by the World Health Organization (WHO) which in its weekly bulletin also takes stock of the covid variants, their distribution, any scientific updates and expert assessments. And he warns: “Based on the evidence currently available, the overall risk related to the Omicron variant remains very high.” The epidemiological situation of Sars-CoV-2 in the world sees the inexorable and “continuous decline in the prevalence of the Delta variant, and a very low level circulation of Alpha, Beta and Gamma”, reads the report updated this week.
Of the 372,680 sequences loaded on the Gisaid platform with samples collected in the last 30 days, almost 90% (89.1%) were Omicron, i.e. 332,155. While 10.7% were Delta (39,804). Finally, 28 sequences were of Gamma variant, 4 of Alpha and two samples were attributed to Mu and Lambda. Countries that saw rapid increases in Omicron cases in November and December have started or are beginning to see a decline in cases. But the WHO invites us not to let our guard down: “Compared to other variants, Omicron has shown a greater capacity for dissemination within the community, leading to a rapid increase in the number of new cases in more countries where it has replaced other variants. , including Delta “.
There appears to be “a lower risk of serious illness and death with Omicron infection than other variants – continues the UN health agency – However, due to the very high number of cases, many countries have seen a significant increase in incidence of hospitalizations, which has put health systems under pressure “. It is the high transmissibility that is highlighted in particular by WHO experts. For example, several studies show a higher secondary infection rate within families than that of the Delta variant (31% for Omicron versus 21% for Delta according to a study conducted in Denmark, for example).
In addition, studies conducted in India and South Africa reported a higher rate of asymptomatic infection at the time of testing among people infected with Omicron than in those with Delta. The higher frequency of asymptomatics “may result in a lower detection rate, and thus further contribute to transmission,” WHO concludes.