“For the first time, we may be witnessing a shift in the epidemiological landscape, with multiple Omicron subvariants emerging at the same time around the world, some of which cohabit within of the same country”, notes Antoine Flahault, epidemiologist and director of the Institute of global health at the University of Geneva (Switzerland), with “L’Express”. In this context, what are the main sub-variants currently circulating? And what are their characteristics?
BA.5, the majority sub-lineage
Identified in April in South Africa, the BA.5 sub-lineage is now the majority in France and internationally, according to the latest data from Santé Publique France. Fatigue, cough, fever and headache are the most common symptoms. “The probability of presenting anosmia (a loss of smell, editor’s note) and ageusia (a loss of taste, editor’s note)” is higher, points to Public Health France. “Le Journal des femmes” points out that a new symptom has been reported by Professor Luke O’Neill of Trinity College in Dublin (Ireland): night sweats. “The disease is different because the virus has changed, with night sweats being a new symptom,” he told Irish radio Newstalk.
For this fall’s vaccination campaign, the Haute Autorité de Santé (HAS) has given the green light to three anti-Covid vaccines adapted to Omicron “in an epidemic context marked by the majority circulation of the BA.5 sub-variant”. The WHO nevertheless qualified by assuring that there was not yet enough data to be able to recommend these mRNA vaccines.
XBB, the recombinant that worries Singapore
Detected at the end of 2021, XBB is a recombinant resulting from the combination of the genetic material of two different Omicron sub-variants. In recent weeks, it has led to a resurgence of the Covid-19 epidemic in Singapore: more than 6,800 cases on Wednesday (on a rolling average over 7 days), against less than 3,000 at the end of September, details BFMTV, which reports data of the Ministry of Health. This new subvariant has also been detected in Europe: in Denmark, Belgium, Austria and the United Kingdom. “The number of severe cases has remained relatively low” and there is “no evidence that XBB causes more severe disease,” the Singaporean ministry said on Tuesday.
According to a study conducted by Chinese scientists, pre-published on October 4 and which has not yet been peer-reviewed, the recombinant XBB would be particularly resistant to antibodies. This would mean that “booster vaccines designed on the basis of BA.5 may not provide broad-spectrum protection against infection”, reports BFMTV.
New symptoms with the BQ.1.1 sublineage?
This sub-variant of Omicron represented 6% of the positive cases whose genomic sequence was analyzed at the end of September in France, reports Le Parisien. “The arrival of the BQ.1.1 variant is not good news. It has the particularity of causing diarrhea and vomiting ”, wrote on Twitter the pediatrician Rémi Salomon president of the medical commission of establishment of the Public Assistance Hôpitaux de Paris, sharing at the same time data which show that this new strain progresses. in France. Nevertheless, “no reliable data allows us to affirm it”, denied for his part Le Parisien.
The case of Khosta-2, cousin of Covid-19
From the same viral family as Sars-CoV-2, this virus was discovered by American scientists in Russia between March and October 2020, reports “It interests me”. Although to date, no case has yet been detected in humans, laboratory analyzes have recently shown that our cells could be infected. In addition, the virus would be resistant to antibodies and vaccines developed against Covid-19 and could have more virulent factors.