Covid-19: UK and South Africa strains spark mutation battle
South Africa’s health minister strongly rejected his British counterpart’s claim that a new variant of coronavirus in the country is more contagious, sparking a battle over Sars-Cov-2 mutations even as the United States said all travelers from the UK must present a Covid-19 test to avoid quarantine.
Concern over mutations in the virus, first detected in the UK before similar but distinct variants were seen in South Africa, continued to spread to more parts of the world on Friday, with Germany, Switzerland and Japan saying they have identified their disease. first cases. Previously, Denmark, the Netherlands, Australia and Belgium said they found the variant linked to the UK.
These developments also come at a time when scientists are racing to find out what implications mutations will have on pandemic and vaccines.
“At present, there is no evidence that the 501.V2 (variant) is more transmissible than the UK variant, as suggested by the British health secretary,” Zwelini Mkhize said in a statement. “There is also no evidence that [it] it causes more severe disease or higher mortality than the UK variant or any variant that has been sequenced worldwide, ”he added.
He was responding to a statement from British Health Secretary Matt Hancock on December 23 that the variant in the African nation was “even more transmissible and appeared to have changed even more.” In the case of both variants, scientists have yet to determine whether the disease is more severe.
So far, around 50 countries have banned travel to and from the UK due to concerns about the new variant. The UK, in turn, has restricted travel from South Africa.
A preliminary mathematical model by researchers at the London School of Hygiene and Tropical Medicine found that the variant, known as VOC 202012/01, is 56% more transmissible than other strains and, although there is no clear evidence, it results in cases The more severe the disease, a greater number of cases could lead to more hospitalizations.
“We could not find clear evidence that VOC 202012/01 results in greater or lesser disease severity than pre-existing variants. However, increased transmissibility is likely to lead to a large increase in incidence, with Covid-19 hospitalizations and deaths projected to reach higher levels in 2021 than seen in 2020, even if restrictions are maintained. regional tiers implemented before December 19. “The researchers said.
Mutations are not unusual in viruses, but one particular variant, first reported by UK authorities on December 14, has 17 changes that scientists say are an unusually high number. These include a change known as N501Y in the Spike protein, which is believed to cause the virus to bind to host cells more strongly.
The same change has been seen in two variants: one spreading in South Africa and another in Wales of the United Kingdom. However, both variants appear to have evolved separately, according to a phylogenetic analysis by Nextstrain.
The origin of the high number of changes in the variant linked to the United Kingdom, also known as B.1.1.7, is still a mystery. A new threat assessment report from the European Centers for Disease Control (E-CDC) said that according to “molecular clock estimates,” Sars-Cov-2 has been mutating at a rate of two changes per month.
VOC-202012/01, compared to the variant that originated in Wuhan, has 29 changes, making a random evolution in an undetected part of the world unlikely. “… Random mutations acquired during virus circulation would not explain the unusually high proportion of peak protein mutations and undetected circulation long enough for the large number of mutations to accumulate (around 10 months depending on current estimates of the molecular clock) is also not very likely due to global travel patterns, ”said the E-CDC.
One of the theories supported by the E-CDC and the UK authorities is that it evolved in a person with compromised immunity. “A possible explanation for the appearance of the variant is prolonged Sars-CoV-2 infection in a single patient, potentially with reduced immunocompetence, similar to what has been described previously. Such a prolonged infection can lead to the accumulation of immune escape mutations at a high rate, ”said the E-CDC.
Determining the origin of the variant will be crucial to prevent further mutations in the virus, which could have implications for the efficacy of vaccines. All the major vaccine manufacturers have said that, at present, the changes do not appear to be significant enough to make their products obsolete.
Even if they do, vaccine manufacturers will be able to make quick adjustments, the CEO of BioNTech, the co-developer of the first approved coronavirus vaccine, said last week.