The international community has been concerned since the emergence of various forms of the Saras-Cove-2 virus in the United Kingdom and South Africa, because, according to earlier data, they are more contagious.
– What are these variants? All viruses are mutated, that is, they change when they replicate.
Sars-CoV-2 has undergone many changes since its appearance, but generally without consequence. However, some mutations may favor their survival, for example, if they reach more infectious.
Variant B.1.1.7, now called VOC 202012/01, was found in the United Kingdom in November, after developing “possibly” in southeast England in September, according to Imperial College London.
After a rapid spread in that country, the variant was detected in dozens of other countries from the United States to South Korea through India, France, and Denmark.
Most of the cases were imported from the United Kingdom, but some have no proven relationship with that country, as in Denmark with 86 identified patients.
The 501.V2 version, now prevalent in South Africa, was found there in October and located in other countries such as the United Kingdom and France.
According to experts, the number of both types of cases is currently underestimated.
Both have multiple mutations, one of which, N501Y, affects the protein “spike” Coronavirus, A tip that acts to engage and penetrate the ACE2 receptor of human cells.
This mutation enhances the ability of the virus for the ACE2 receptor. Although according to the European Center for Disease Prevention and Control (ECDC), “there is no clearly established relationship between ACE2 adherence and increased transmission, it is possible”.
More transferable?
Several scientific studies, mainly based on model analyzes and not yet evaluated by other experts according to scientific protocols, conclude that the British version is much more permeable, confirming the initial evaluation of the group NERVTAG of researchers Does, which supports the British government and who estimated the difference between + 50% and + 70%.
Thus, according to the London School of Hygiene and Tropical Medicine (LSHTM) calculations, the British version would be between 50–74% more infectious. For Imperial College London, which analyzed thousands of genomes of the Sars-CoV-2 virus, the infectious capacity is over 50–75% and the reproduction rate (R) is between 0.4 to 0.7 compared to normal viruses.
Preliminary findings on the South African version also show greater transmission, but less data are available.
In the absence of conclusive results, some experts are cautious.
“We have to be vigilant. Incident is a combination of factors that take into account the characteristics of the virus, but also implement preventive and control measures” To fight Kovid-19, Director of Infectious Diseases Bruno Coinguard, AFP Tells the French health agency Saint Peblic from France.
More dangerous?
ECDC states, “None of the available information suggests that infection with these strains is more serious.” But the risk is “higher in terms of hospitalization and death”.
Furthermore, “greater contagion ultimately equates to a much stronger event and, therefore, more significant pressure on the health system, even if the malignancy (of the variants is similar)”, according to Coignard.
A version of Sars-CoV-2 that was “50% more infectious would pose a bigger problem than a 50% more lethal version,” British epidemiologist Adam Kucharsky said on Twitter, based on statistical evidence: fertility rates With 1.1, 0.8% and 10,000 mortality rates infected, there will be 129 deaths in a month. But if the rate of contagion increases to 50%, then the death toll will increase to 978.
On the other hand, the first study of the British edition shows that it is more contagious than the general stress among youth under 20, raising the question of closing schools.
The LSHTM study therefore predicts that measures taken in November during imprisonment in the UK would not be effective in controlling the epidemic, “until schools, colleges and universities were also closed”.
Do they affect the effectiveness of vaccines?
“For now, we do not have enough information to say” that these variants represent “a risk for vaccine effectiveness”, ECDC estimates.
However, with the available data, “experts believe that current vaccines will be effective against these strains on Wednesday,” said Henry Wallke of the United States Center for Disease Prevention and Combat on Wednesday.
German laboratory BioNTech, the manufacturer with Pfizer, the first vaccine against Kovid-19 authorized in the world, guaranteed that it would supply a new product in “six weeks” to respond to a mutation, if necessary. Can do.
How to face the variants?
Since it is not possible to stop the spread of these variants, the objective is to “delay” as much as possible, according to Coinguard.
The ECDC recommends that affected countries take measures similar to those at the onset of an epidemic, such as limiting travel and testing on people in at-risk areas. It also calls for control of events of these types, multiplying the sequencing of the virus.
According to epidemiologist Arnaud Fontanet, a member of the Scientific Council advising the French government, some later PCR tests may indicate the presence of a British version.
Personally, “we must also be strict with preventive measures”, Drs. Warns Walké, hygiene in hand, in the context of wearing masks, among other approaches.
