Covid: What do we know about BA.4.6, the new Omicron sub-variant already dominant in some US states?

While BA.5 is the dominant sub-variant in the world, another version of Omicron is experiencing meteoric rise in the United States.

It was the CDC, the US government’s disease control and prevention agency, which placed BA.4.6, a new subvariant of Omicron, on the list of “variants of concern” these days.

According to US authorities, the sub-variant has been circulating for several weeks in the United States and has already surpassed all other Omicron variants in four states: Iowa, Kansas, Missouri and Nebraska.

Last week, BA.4.6 already accounted for 4.1% of Covid cases nationwide. It was placed on the list of variants of concern because BA.4.6 exhibited “greater transmissibility, reduced efficacy of treatment, increased severity or reduced neutralization by antibodies”, according to the CDC definition.

BA.4.6 is not only present in the United States since it has been spotted in 43 other countries.

Few data available

Scientists currently have little data on whether BA.4.6 has the potential to be as transmissible as BA.5, another Omicron subvariant that is widely dominant worldwide.

However, specialists agree that given the few new mutations present, BA.4.6 should not be “more worrying than BA.4/5”. This does not mean that it will be weak, BA.5 having been described as “the worst version of the virus that we have seen since the start of the pandemic”.

If it causes an equally spectacular immune escape, with as many reinfections, BA.4.6 will further complicate the medical response to finally put an end to this pandemic.

The next few weeks will reveal more about this variant. But it is his response to Omicron-specific vaccine updates that is most anticipated.

–