Omicron variant, WHO: “Contagions double in 2-3 days”

It is now present in 110 countries. In Italy it will be dominant in the coming weeks

The Omicron variant is rampant in the world, where it is now present “in 110 countries” with a doubling time “of infections” of 2-3 days. “In Italy it stands at a little over 28% and will be dominant in the coming weeks. according to the ISS. While the World Health Organization points out that “there is strong evidence that this new variant has a substantial growth advantage over Delta: it is spreading much faster in countries with documented community transmission”.

“Estimates on growth rates in South Africa are now falling”, WHO reports, specifying that “it is still uncertain to what extent the rapid growth rate observed since November 2021 can be attributed to immune evasion or the increase. of transmissibility, but it is probably a combination of both. At present, estimates of Omicron’s generation times are still needed to better understand the observed dynamics. ” Likewise, we need “more data” on the clinical severity of Omicron infections, on the effectiveness of vaccines, especially in the case of people with only 1 or 2 doses, on reinfections.


The Omicron variant in Italy today represents about 28% of infections and is soon to become dominant. The covid picture, with strong variations from region to region, is outlined by the estimate based on the preliminary analyzes of the swabs collected for the rapid survey of 20 December, as communicated by the Higher Institute of Health (Iss) in a note. The analysis – specifies the ISS – was based on about 2 thousand swabs collected in 18 regions and autonomous provinces, in which those samples in which one of the three genes that is normally searched for in tests were considered as possible positive for Omicron molecular diagnostics (so-called S gene dropout) or other screening tests to exclude the presence of the Delta variant, currently still dominant.

A more precise indication on the prevalence estimates – announces the Institute – will come from the completion of the flash survey, the results of which will arrive on 29 December, while a new flash survey is already scheduled for 3 January to strictly assess the evolution of the epidemiological situation. . Comparing the results of the flash survey conducted with the collection of samples on December 6 and those of this preliminary estimate, the doubling time of the variant is approximately two days in line with that already found in other European countries. “Even if the results are still preliminary, the estimate confirms the great speed of diffusion of the variant, which seems to give very widespread outbreaks in a short time and is about to become a majority in a short time, as is already happening in several other European countries”, says the president of the Higher Institute of Health (Iss), Silvio Brusaferro.

“On the basis of the data available today, the weapons available are vaccination, with a timely third dose for those who have already completed the first cycle, and individual and collective measures to limit the spread of the virus, from the use of masks to limitation of contacts and gatherings “, he adds.