When will the Covid-19 pandemic end? The World Health Organization (WHO) estimated on May 4 that two subvariants of Omicron, identified in South Africa, were behind the fifth wave hitting the country, the most affected on the African continent. by disease. The momentum is strong: the number of new recorded cases of Covid-19 in South Africa has increased from some 3,500 cases on May 3 to around 7,500 a week later, an increase of more than 100%. Franceinfo summarizes what we know about these two sub-variants, baptized BA.4 and BA.5, which carry this new wave.
They were discovered at the end of 2021
“South African scientists, who identified Omicron late last year, have now flagged two other Omicron sub-variants, BA.4 and BA.5, as causing a peak of cases in South Africa”WHO Director-General Tedros Adhanom Ghebreyesus said in early May.
They could be discovered “because South Africa is still doing the genetic sequencing [du virus] that other countries have stopped doingunderlined the leader of the WHO. In many countries we cannot see how the virus mutates. We don’t know what awaits us.”
The Omicron variant was first detected in South Africa in November 2021. Until now, it counted “four lines named B.1.1.529 [le premier à avoir été appelé Omicron]BA.1, BA.2 and BA.3″, reported the WHO in January. Around the end of 2021 and the beginning of 2022, the BA.2 variant was discovered in several countries, including France.
They are more contagious than the other subvariants
BA.4 and BA.5 “seem more transmissible than the previous ones” sub-variants of Omicron, estimated with France 24 the epidemiologist Antoine Flahault. Their Spike protein, which allows the virus to enter our cells, carries two mutations. The one called L452R increases its transmissibility, causing it to be approximately 20% more contagious than the BA.2 subvariant. It is not unknown since it is present in the Delta variant, which is particularly contagious, which raged in the summer of 2021.
The other mutation, called F486, “is associated with reduced neutralization of antibodies”, according to Antoine Flahault. It could lead to a potential decrease in the effectiveness of the vaccine against these two sub-variants, he notes to The Dispatch.
On the other hand, the dangerousness of these two sub-variants is still unclear. “It is too early to know whether these new subvariants can cause more severe forms of the disease than other Omicron subvariants”said the boss of the WHO. “So far, South African authorities are not seeing a significant upsurge in the severity of these new variants”notes Antoine Flahault.
They have already been detected in France
The BA.4 and BA.5 subvariants are in the majority in South Africa, as shown by epidemiologist Tulio de Oliveira, director of the Center for Innovation and Response to Epidemics, a South African research institute.
South Africa had multiple waves of infections, the first dominated by multiple lineages (> 50 614G lineages), the second by Beta, them Delta, Omicron BA.1, BA.2 and Omicron BA.4 and BA.5. pic.twitter.com/19n8PVvXIJ
— Tulio de Oliveira (@Tuliodna) May 8, 2022
In France, the BA.2 sub-variant of Omicron is still very largely dominant, according to Public Health France (99% of sequences from the last survey). But BA.4 and BA.5 have already been detected in France. If they are still very much in the minority, they are scrutinized and subject to“a enhanced surveillance”writes Public Health France in its epidemiological bulletin of May 5. “As of May 2, 2022, two cases of BA.4 and six cases of BA.5 have been confirmed in France and are under investigation”specifies the health agency.
For Antoine Flahault, vigilance is required with regard to previous episodes. “Several waves of contamination, which occurred in the past in South Africa, preceded those which occurred a little later in Western Europe.recalls the epidemiologist in the columns of The Dispatch. This could be the case again with BA.4 and BA.5, which could arrive in Europe before mid-June.” “This wave of contaminations will not necessarily be associated with a notable increase in hospitalizations and deaths, but we must follow the current South African development very closely and prepare”insists the specialist with France 24. According to Tulio de Oliveira (link in English)the situation in South Africa may “lead the whole world” towards the future of the pandemic.