Mutations to the SARS-CoV-2 coronavirus that causes Covid-19 will not affect the effectiveness of vaccines, a study shows.
The virus has mutated at a critical location since it first emerged in Wuhan late last year, and there were concerns future changes could render vaccines useless.
In the early days of the Covid-19 pandemic the dominant guise of the virus was a variant now called the 'D strain'.
However, a mutation at one specific location, called position 614, turned one amino acid from a D (aspartate) to a G (glycine), and this 'G strain' is now dominant.
Viral mutations are common and can make creating vaccines difficult as it causes the virus to change shape, rendering previous vaccines useless, as is the case with seasonal flu.
Researchers were concerned that if this was the case for SARS-CoV-2 a new vaccine would be needed for every time the coronavirus mutated.
However, a study from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) has found the change from the D to G strain will not impact on vaccine effectiveness.
They are hopeful that any future mutations will also not impact vaccine efficacy.
Mutations to the SARS-CoV-2 coronavirus that causes Covid-19 will not affect the effectiveness of vaccines, a study shows. The virus has mutated at a critical location since it first emerged in Wuhan late last year
SARS-CoV-2, the virus which leads to Covid-19, has a protein on its surface which binds to a receptor on cells called ACE2 and this is how it invades the body
The G strain of the virus initially accounted for barely any SARS-CoV-2 positive cases, and now makes up around 85 per cent of all cases worldwide.
It emerged due to a mutation called D614G, which occurred at position 614 and is located on the S-protein viral spike which sticks out from the coronavirus and latches onto the human receptor ACE2.
This human receptor protrudes from surface of some cells and acts as a gateway for the coronavirus, triggering an infection.
One recent study from the US found 99 per cent of cases in one hospital were of the G strain.
As the mutation is on this critical part of the virus, scientists feared it would mean the virus may rapidly change shape.
If this was to occur, it could mean a new vaccine would be needed every time a new mutation emerged, similar to seasonal flu.
Professor Seshadri Vasan leads the Dangerous Pathogens Team at CSIRO and is senior author of the latest paper.
His team used blood samples from ferrets to see how the mutation would impact vaccines.
The animals were infected with either the D or the G strain and given a vaccine currently in development.
A study by the Royal Society's SET-C (Science in Emergencies Tasking – COVID-19) task force studied the one major mutation SARS-CoV-2 underwent.
It is located on the S-protein which sticks out from the surface of the virus.
This spike latches on to the ACE2 receptor of human cells, tricks it into opening the cell, and allows the pathogen to infect a person.
At one specific location — residue 614 on the S1 terminus — the original form of the coronavirus had the amino acid aspartate, labelled with a D.
However, a random mutation saw this amino acid replaced with a glycine, labelled with a G.
The so-called D614G mutation was seen in barely any samples taken in February.
However, by March, more than a quarter (26 per cent) of isolated SARS-CoV-2 strains contained the mutation.
By May this figure had reached 70 per cent.
An estimate for October claims 85 per cent of global cases are now due to the D614G mutation, making it by far the most dominant one seen globally.
This mutation appears to help more virus infect a person and for more efficient infection of cells.
The D614G virus is also almost always accompanied with three other minor mutations. The role of these changes remains unknown.
Data from the peer-reviewed study, published in the journal npj Vaccines shows the vaccine worked just as well on either strain.
Professor Vasan said: 'This is good news for the hundreds of vaccines in development around the world, with the majority targeting the spike protein as this binds to the ACE2 receptors in our lungs and airways, which are the entry point to infect cells.
'Despite this D614G mutation to the spike protein, we confirmed through experiments and modelling that vaccine candidates are still effective.
'We've also found the G-strain is unlikely to require frequent "vaccine matching" where new vaccines need to be developed seasonally to combat the virus strains in circulation, as is the case with influenza.'sonos sonos One (Gen 2) - Voice Controlled Smart Speaker with Amazon Alexa Built-in - Black read more
CSIRO Chief Executive Dr Larry Marshall said the research was critically important in the race to develop a vaccine.
Dr Marshall said: 'This brings the world one step closer to a safe and effective vaccine to protect people and save lives.