New SA Covid variant: Vaccines should work, but further mutation could pose threat
- The new United Kingdom and South Africa variants of SARS-CoV-2 are different, but both make the virus more transmissible and both have more genetic variations than previously observed variants
- There is no evidence that the current mutations will make available vaccines less effective
- But if the variant is allowed to spread and evolve, that could compromise the effect of the vaccine, a scientist warned.
- For more articles, go towww.BusinessInsider.co.za.
The new Covid-19-causing virus variants in the United Kingdom and South Africa are different, but have a similar mutation that makes them more transmissible, say scientists. And this is not the first time that they have seen it.
On Monday, both South Africa and the United Kingdom were chafing under stricter restrictions, following the detection of new variants. Numerous countries have halted flights to and from the two countries. And the UK variant has now been detected in Italy, Denmark, Netherlands, Australia and Gibraltar, Sky News reports.
“They are definitely different, but they have two things in common,” says Dr Richard Lessells, an infectious diseases specialist and group leader at the KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP) at the University of KwaZulu-Natal. One is that the variants (or lineages) have more new mutations than previously seen in the SARS-CoV-2 RNA.
“This lineage differs by between 20-40 mutations from the original Wuhan virus, and by 20 mutations from South African viruses sequenced in early September,” Jinal Bhiman, principal medical scientist at the NICD, told Business Insider SA.
In South Africa, there has been anecdotal evidence that the variant has been causing younger people and otherwise healthy people to get a more severe form of Covid-19, Science reports. However, Bhiman says: “We do not know how [or] whether these variants cause different disease outcomes yet, but we are urgently investigating this.”
The UK variant (called B.1.1.7) has 17 new mutations.
The second commonality between the UK and South African variants is a specific mutation on the virus genome, N501Y, says Lessells.
“N501Y” refers to the location on the genome that is part of the region that encodes for the virus’ distinctive “spike protein”. This prickly outer surface is how the virus latches onto human cells. “The virus seems to be able to latch on more easily with this change in the virus,” says Lessel;s.
However, this is not the first time scientists have observed the N501Y mutation. “An examination of the global GISAID SARS-COV-2 sequence database (a global initiative that shares genome data) shows that this N501Y mutation was actually present in variants circulating, sporadically, much earlier in the year outside the UK: in Australia in June-July, USA in July and in Brazil in April, 2020,” said Dr Julian Tang, an honorary associate professor and clinical virologist at the University of Leicester.
“Whether or not these viruses were brought to the UK and Europe later by travellers or arose spontaneously in multiple locations around the world (in response to human host immune selection pressures) requires further investigation.”
Lessells thinks that the virus has a predisposition to mutate at this point on its genome. “In Australia, that was not the same as this virus we’re seeing now – they just had in common this mutation, nothing else,” he says. “Like the UK, it’s definitely different. It suggests that the virus is more likely to evolve mutations at this position.”
NICD’s Bhiman says: “In Australia, a virus with the common mutation found in the SA and UK lineages was detected, however this virus was unable to spread as it was effectively contained.”
Lessells notes that the Australian example also shows that it is possible to curb these mutations. “It disappeared, it didn’t circulate for long, and that is important because it shows that you can still stop the spread of this virus…. With a good public health response and following preventative measures, we stop the spread, we stop the evolution.”
There is also no evidence that the N501Y alteration in the spike protein will make vaccines less effective.
The two leading vaccines specifically target this spike protein, however experts, including Lessells, do not believe that this will affect their efficacy as only one amino acid is affected.
“The important thing about vaccines, they induce antibodies that target different parts of that spike protein,” Lessells explains. “If you have a change in one position, it may not affect the response to the vaccine. But... if we allow the virus to continue to spread and evolve, that is more likely in time to lead to changes that may compromise the effect of the vaccine.”
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