The sub-variant BA.2 (the so-called Omicron 2) is more transmissible than Omicron 1 (BA.1), does not give a more severe disease and is unable to reinfect those who have already fallen ill with Omicron 1. They are the three main points that emerged from the meeting of the working group of the World Health Organization dedicated to the monitoring of variants of Sars-CoV-2.
The group clarified that BA.2 deserves to be kept under close surveillance: despite the decline in cases of Covid-19 infections on a global scale, it continues to gain ground compared to BA.1.
"Studies are underway to understand the reasons for this growth advantage, but initial data suggests that BA.2 is inherently more transmissible than BA.1, which currently still remains the most common Omicron sub-lineage," WHO says. a note in which it clarifies that the advantage of BA.2 compared to BA.1 is still much smaller than that which the latter has compared to Delta.
INFECTION RISK - As for the risk of re-infection in someone who has already fallen ill with Omicron, sporadic cases have been reported to date, however, "initial data from population-wide reinfection studies suggest that BA infection. 1 provides strong protection against BA.2 reinfection, at least for the limited period for which data are available, "WHO clarifies.
AGGRESSIVENESS - Regarding the aggressiveness of the new variant, some studies had observed in animal models never previously exposed to the virus that Omicron 2 could cause a more severe form of disease than Omicron 1. Population data, for the moment, seem to disprove it. WHO has taken into consideration those from South Africa, the United Kingdom and Denmark, "where immunity from vaccination or natural infection is high," the World Health Organization specifies. "In these data, no difference in severity was reported between BA.2 and BA.1."
(Unioneonline / vl)
