According to some experts, the R0 of the Omicron variant could be 10, the incubation time has been reduced from 4-6 days to just 3 days: this is the reason for the explosion of infections
Slowly the puzzle on the characteristics of the (very studied) variante Omicron. Many preliminary studies give important information, starting with what is now a clear question: Omicron (B.1.1.529) much more transmissible than previous variants. In South Africa, where the variant was identified on November 24 (to be classified two days later as a variant of concern by the World Health Organization), Covid infections tripled in three days in early December, with cases grown more than 300% in one week.
A tsunami of cases
That the virus is running fast is confirmed by a study by Imperial College London, according to which Omicron has a reinfection capacity 5.4 times higher than Delta. Furthermore the incubation time appears shortened to Three days, compared to 4-6 of the previous variant. This means that, even if the probability of hospitalization for Omicron is lower (this is confirmed by studies conducted in South Africa, England and Scotland), hospitals risk the crisis precisely because of the high and rapid diffusivity. A preliminary South Korean study shows that Omicron has a generation time (i.e. the time between two infections in a transmission chain) of 2.2 days, compared to Delta’s 3.3. According to some experts, Omicron’s R0, or the basic reproduction number that represents the average amount of secondary infections produced by each infected individual, could be 10 (compared to 2.5 for the original Wuhan strain). I am very concerned that Omicron, being more transmissible and circulating at the same time as Delta, is leading to a tsunami of cases WHO Director General Tedros Adhanom Ghebreyesus said a few days ago at an online press conference. This, he stressed, I will exercise enormous pressure on the already exhausted health workers and on health systems, which are close to collapse.
The infections double in 2-3 days
The overall risk associated with the new Omicron variant remains very high. Consistent evidence shows that this variant has a growth advantage over Delta with a doubling time of 2-3 days – the WHO always explains in the weekly epidemiological report -. A rapid increase in incidence is observed in a number of countries, including those where Omicron has become dominant, such as the United Kingdom and the United States. the rapid rate of growth is likely to be a combination of immune evasion and the inherent increased transmissibility of the variant. Omicron is quickly supplanting Delta in several countries (in Italy it may have exceeded 50%): the Netherlands, in lockdown, announced that the new variant is now officially responsible for the greatest number of infections, even if the numbers are decreasing. Even in South Africa, after the initial boom and reaching the peak, the infections have decreased: the hope that, as Omicron spreads quickly, it can just as quickly loosen its grip.
Hospitalizations are also on the rise
Massimo Andreoni, head of infectious disease at the Tor Vergata Polyclinic in Rome, underlines that the transmissibility of this variant is of great concern because if the cases increase so much, the hospitalizations will also increase. Moreover, he adds, the idea is being consolidated that Omicron is a little less virulent than the Delta, but it will be no less than 10 years before it becomes a simple cold. The Higher Institute of Health (Iss) does not hide the concern for the number of new cases registered in all regions, especially in the North. Not only that: it is revealed a high incidence of infections between 6 and 11 years (age range for which the Pfizer vaccine is authorized with a third of the dose) and vaccination efficacy which, after 5 months from the completion of the primary course, decreases compared to symptomatic infection from 71.5% to 30%, while remaining effective against 82.2% severe disease.
Protect children
The Ministry of Health has given the green light to advance the third dose from 5 to 4 months after completion of the primary course. The booster proved effective in restoring high levels of protection against symptomatic infection and severe disease
, respectively at 71 and 94%. the administration of booster doses is underway for the 16-17 year old age group and for frail children between 12 and 15 years old. In addition, vaccination continues in the 5-11 year range, on which, says the president of the ISS Silvio Brusaferro, good membership. That Omicron heavily affects the pediatric range confirmed by admissions for Covid in pediatric hospitals in New York, increased 5 times, while nationally, in the United States, the growth of 35%.
January 1, 2022 (change January 1, 2022 | 08:28)
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