Viruses are experts at mutation – but there is no need to panic

Yesterday, while outlining enhanced restrictions across the southeast of England, health secretary Matt Hancock made some alarming comments about the discovery of a new variant of Sars-CoV-2 (the virus that causes Covid-19).

This new variant is associated with recent infections in England; no changes to severity of disease have been described. More details have since emerged about the new variant, with research being led by the Gupta Lab at the University of Cambridge. It shows that this new strain is characterised by several mutations that may affect the biology of the virus.

Scientists right across the world are actively tracking Sars-CoV-2, using modern genetic methods, and we take all changes in the virus seriously. But this new variant shows little cause for increased concern among the public – at present.  

However, virologists, epidemiologists and clinicians are doing their due diligence and investigating this new variant in detail to try and ascertain its potential impact, if there is any. All current mitigations in place, such as mask-wearing, social distancing and the all-important vaccine should not be majorly affected by these changes to the virus.

Viruses are experts at mutation and evolution. Genetic changes like those being seen in this new strain are completely normal, are to be expected, and we need to get used to them. In fact, it is these changes that allow us to track the spread of the virus between people and countries across the world.

The UK is one of the world leaders in tracking the evolution and mutations of Sars-CoV-2 (and many other viruses). There are teams actively finding, sequencing and analysing Sars-CoV-2 genomes in real time. One example of the use of this surveillance can be seen in the discovery of this new virus variant.

While viruses like Sars-CoV-2 are replicating within the cells lining our nose and lungs, they will make mistakes when copying their genetic material. These mistakes can be thought of as misspellings of the words that compose their genome; they may even lead to the removal of whole words; and sometimes the virus will introduce new words where there were none before. These changes – or mutations – essentially happen at random but can be fuel for evolution, which can in some cases lead to functional differences between mutants.  

Mutations happen to the influenza viruses each year, which is why we need to get a new, updated vaccine every winter. This potential of viruses to mutate and escape immunity is one of the concerning aspects of virus evolution, including that of Sars-CoV-2.

In particular, the new Sars-CoV-2 variant carries at least seven mutations, including a deletion of two letters (or amino acids) making up the spike protein and six other changes in the spike. Spike is the bit of the virus used to get inside our cells and is the major component of any Covid-19 vaccine. Researchers identified a cluster of 350 instances of this variant in England. What makes these particular mutations a concern is that they lie in regions of spike that we know are involved in how the virus binds and gets into our cells, but also that they are bits our immune system sees. We already have some information about some of the mutations from experiments, the results of which were released last month from the lab of Professor Paul Duprex at the University of Pittsburgh Center for Vaccine Research, and the Gupta Lab.

Furthermore, some of these mutations have popped up on more than one occasion, often co-incident with each other, suggesting some functional relevance to the virus. Antibodies that attach onto these regions stop the virus infecting our cells and mutations at these regions allow the virus to escape our antibody defences. The effect of all seven changes on virus biology is, however, unknown at present.

To determine the effect of these mutations on virus biology, how it infects and spreads between people, and whether it will be blocked by our immune system, researchers will now look in greater detail at how the variant is spreading. However, as it is challenging to clearly determine the impact of small mutations on virus biology under natural conditions, and especially unravelling that from epidemiological factors and random chance, incorporating experimental data comparing the old virus with the new variant will be of great help.

New variant or not, Sars-CoV-2 remains a highly infectious and pathogenic virus. Vaccines against Covid-19 will be critical in our fight against Sars-CoV-2 and should usher in some semblance of normality in the coming year. Together with vaccination, we know how to beat Covid-19, using a blend of interventions, including mask-wearing, distancing and a functional test, trace and isolate system. The measures in place are likely robust enough to protect against any new variants that emerge now or in the near future.

We need to worry more about dealing with the virus we have now than any future variants. In saying that, we must also get used to mutation. The longer Sars-CoV-2 is spreading through the population, the more mutations and variants we are going to have to deal with.

Connor Bamford is a virologist at the Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast