Should the Covid XBB 1.5 variant scare France?

One new variant of Covid is monitored in France and around the world. This is the variant XBB 1.5, a subvariant of XBBitself derived from two sub-lineages of BA.2 (Omicron). The World Health Organization (WHO)”closely monitoring the situation, assesses the risk of this sub-variant and will report accordingly” said Tedros Adhanom Ghebreyesus, Director General of WHO on January 4, 2023. XBB 1.5 has been detected for the first time to the United States on October 22, 2022 where he now represents 40% of sequences According to the US Centers for Disease Control and Prevention (CDC). “It is the most transmissible subvariant that has been detected to date“ informed Maria Van Kerkhove, technical manager for the management of Covid-19 at the WHO during a press conference in Geneva on Wednesday January 4. “If a new variant, whatever it is, were essential in Europe, he would be responsible in France for a 10th epidemic wave, with a number of morbidities and deaths and therefore a certain pressure on the hospital system, but not commensurate with what we have experienced before“, explains Bruno Mégarbane, head of the resuscitation service of Lariboisière (Paris) on LCI January 3.

What is the XBB 1.5 variant?

The XBB 1.5 variant is a subvariant of XBB. The variant XBB is a recombinant derived from the Omicron sublines BJ.1 (sub-lineage of BA.2.10) and BM.1.1.1 (sub-lineage of BA.2.75). As a reminder, Omicron has been the majority Covid variant in France since 2022. It had replaced the Delta variant. Many sub-lineages of Omicron circulate today in France.

Is the XBB 1.5 variant present in France?

To date, XBB.1.5 is circulating in France at very low levels. “Alone 15 cases have been identified by sequencing to date” indicated Étienne Simon-Lorière, head of the RNA virus evolutionary genomics unit at the Institut Pasteur to our colleagues at Parisian January 2, 2023. XBB 1.5 can it become the majority? “It’s quite difficult to predict. It will take a sufficient number of successful introductions for the virus to have the opportunity to compete with the diversity of lineages already present.“replied Etienne Simon-Lorière.

Is XBB 1.5 more contagious than Omicron?

XBB.1.5 is a sub-lineage of Omicron which progresses faster than the previous ones (BA2, BA4, BA5…°. This new sub-variant “arrive at more easily infect people who already have immunity, therefore those who have already been infected or who have been vaccinated” said Mircea Sofonea, epidemiologist, on LCI on January 3. “There is a suspicion of gain in contagiousness of this subvariant, which binds more easily to human cells“, continues the epidemiologist. This contagiousness is linked to a mutation of the virus that causes an “immune escape” that is to say, it manages to circumvent the immunity of vaccinated and/or infected people. XBB.1.5 is more efficient at binding to the ACE2 receptor of human cells, which are like a gateway for the Covid virus, explains researcher Yunlong Cao on his account Twitter. “The lineage is currently estimated to have a large growth advantage over previously circulating lines in North America (139%) and Europe (137%), although these estimates are associated with significant uncertainty.” indicates theECDC January 5. It would have the second highest growth advantage to date, second only to BA.1. To date, “There is insufficient information available to assess any change in severity of infection associated with the XBB 1.5 variant” nuance the ECDC.

What are the symptoms of the XBB 1.5 variant?

So far, there have been no posts dedicated to the symptoms of XBB 1.5. As a reminder, the Omicron variant and the sub-lineages that have spread in France have generally been associated with relatively mild symptoms, close to a big cold with some flu symptomsand always fatigue.

What is the presence of the XBB 1.5 variant in the world?

This lineage was first detected in the United States on October 22, 2022 and has been increasing ever since. As of January 3, 2023, 3,456 sequences belonging to XBB.1.5 had been deposited with the ECDC. Most come from the United States (3,080 sequences) and from the United Kingdom (106 sequences). The variant has also been detected in several other countries, including Denmark, France, Austria, the Netherlands, Germany, Italy, Spain, Sweden, Iceland, Belgium, Czech Republic, Portugal and Ireland.

Sources:

– Update on SARS-CoV-2 variants: ECDC assessment of sublineage XBB.1.5, ECDC, 5 January 2023

– Variant proportion monitoring, CDC