One variant chases another. Recently discovered in South Africa, the Omicron variant is already present in at least 38 countries. In the coming months, it could replace the hitherto dominant Delta variant, which itself had supplanted the Alpha variant … Which had previously imposed itself against the initial strain of Covid-19.
But by what mechanism does a variant appear and impose itself on its precedent? The answer may lie with immunocompromised patients.
The virus is present in the body for months
If to date, almost everything remains to be discovered about this new Omicron variant, we know that it has around thirty more mutations than the initial strain, located in the famous Spike protein, the key to the entry of the virus into the ‘organization. Among these 32 mutations, some known, suggest that this strain could be even more transmissible than the previous ones. The unprecedented mutations make it difficult to predict the effects of this variant on the pandemic in the weeks and months to come.
But how did a variant carrying so many mutations emerge? Among the hypotheses studied, “immunocompromised patients could be a source of emergence of potentially dangerous variants of Sars-CoV-2”, concludes a scientific study recently published in the journal Nature Communications. The authors, researchers at the Institute of Virology at the University of Friborg, in Germany, looked at the effects of Covid-19 on these patients whose organism, weakened by the disease (HIV, cancer, transplant or immunosuppressive therapy), struggles to fight off the virus. Patients who could constitute a breeding ground for the development of new variants. One of the patients studied, a kidney transplant recipient who contracted Covid-19, tested positive for the virus for 145 days.
“In these people with a weakened immune system, the virus can stay in the body for months. During this period when it replicates, the virus will analyze the weakened immune system and modify itself to bypass it, and this is how mutations are born. Because the fact that the virus is not attacked by the immune system is in itself mutagenic ”, explains Dr. Benjamin Davido, infectious disease specialist and referring doctor for the Covid-19 crisis at the Raymond-Poincaré hospital in Garches.
Stem viral circulation
Thus, South Africa, which had already seen the emergence of the Beta variant, “is one of the countries most affected by HIV in the world. The latter weakens immunity, which is why variants classified as worrying are emerging there, adds Dr. Davido. That, and the low vaccination coverage in the country and on the African continent ”. However, insufficient vaccination coverage and screening level, especially in Africa, constitute “a perfect recipe for variants to reproduce and amplify”, summarizes the Director General of the World Health Organization (WHO ), Tedros Adhanom Ghebreyesus.
But variants can also emerge in our latitudes. “A year ago, the United Kingdom, under the leadership of Boris Jonhson, chose to let the virus circulate. And a few weeks later, the English variant, renamed Alpha, emerged and replaced the initial strain from Wuhan, recalls Dr Davido. This shows once again that the more actively the virus circulates, the greater the chances of mutations appearing. Hence the need to stem the viral circulation. However, there are also many immunocompromised patients in France and in Europe, another 6 million eligible people who are not vaccinated, and the general population called upon to receive its booster dose due to the decline in immunity conferred by vaccines “.
Vaccinate to avoid “variant incubators”
So to curb the virus and its desires to mutate, “we must accelerate the global vaccination, insists the infectious disease specialist. First of all in immunocompromised people, because beyond the individual benefit for these vulnerable patients, vaccination represents a collective issue, since a vaccinated immunocompromised person has less risk of becoming a variant incubator ”. It is with this in mind that, in an opinion issued on November 30, the High Authority for Health “recommended to vaccinate children aged 5 to 11 living in the entourage of immunocompromised people or those of vulnerable people not protected by the disease. vaccination ”.
But if France can boast of having one of the highest vaccine coverage in the world, “it is impossible to get out of the pandemic as long as the entire planet is not vaccinated”, insists Dr. Davido. While many countries, including the United States, Germany, France and Israel, have launched vast campaigns to administer a third dose, the WHO deplores the low coverage in the poorest countries and calls for international solidarity. “We have in France – and this is the case in all rich countries – a fairly self-centered vision of Covid-19. In the face of a pandemic, the fight can only be effective if it is global and coordinated, insists Dr Davido. Perhaps it would be necessary to go through compulsory vaccination here so as not to waste any more time, and then concentrate on the vaccination of forgotten countries, ”suggests the infectious disease specialist.
In the meantime, Omicron continues to progress across the world, and several cases have been identified in France. At the same time, France undergoes a fifth wave caused by the Delta variant. This Monday, at the end of a Health Defense Council, the head of government Jean Castex announced the strengthening of health protocols in primary schools and called on the French to “ease off” in social interactions. On the vaccination side, the Prime Minister plans to open vaccination every 5-11 years, “if possible by the end of the year”, and ensures that those over 65 can be vaccinated without an appointment. you “whatever the center”.