BQ.1.1, the new and constantly progressing Omicron sub-variant

Detected in France in September, a new sub-variant of Omicron, baptized “BQ.1.1”, continues its inexorable progression. So much so that it seems set to supplant the BA.5 variant from Omicron, currently the majority.

BQ.1.1 derives from the BQ.1 sub-lineage, which itself originates from BA.5. This newcomer seems to have emerged in Nigeria in July. It has since spread in Europe, notably in France, Belgium, Denmark and Italy, as well as in other countries, including Japan, the United States and Australia.

At the very beginning of October, the European countries with the highest proportion of samples infected with these new sublineages (BQ.1 and BQ.1.1) were France (19%), Belgium (9%), Switzerland (9%), the United Kingdom (8%), the Netherlands (6%) and Italy (5%). France is the European country where the prevalence of BQ.1.1 is the highest. In the United States, BQ.1 and BQ.1.1 account for 9.4% and 7.2% of Covid-19 cases respectively. These sub-lineages together occupy the second place in terms of prevalence after the BA.5 variant (62.2%).

Greater resistance to neutralizing antibodies

The daily growth rate of BQ.1.1 is 11% higher than that of BA.5. In a report by the European Center for Disease Control and Prevention (ECDC), published on October 21, models suggest that Covid-19 cases attributable to BQ.1 and BQ.1.1 will represent, between mid-November and early December , more than half of infections. And, at the beginning of 2023, according to the ECDC, it would be more than 80% of the cases in the Europe zone which would be due to these sub-variants.

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The growth advantage of BQ.1.1 compared to the circulating variants is undoubtedly due to the fact that it has a strong immune escape. Indeed, the mutations present in the spike protein of the virus envelope, which serves as the key to entering cells, allow it to thwart the action of antibodies. However, to date, no data indicate that BQ.1.1 is associated with a greater severity of infection.

Two studies by Chinese and American teams, communicated on October 4 and October 20 on the BioRxiv site (not yet reviewed by peers) suggest greater resistance of BQ.1 and BQ.1.1 to the action of neutralizing antibodies by compared to BA.5. Peking University researchers indicate that BQ.1.1 defeats therapeutic monoclonal antibodies, including Evusheld, used in subjects at risk of developing a severe form of Covid-19.

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