22 Jan SARS-CoV-2 variants: What’s in a name?
Professor Sharon Peacock, Director of the COVID-19 Genomics UK (COG-UK) Consortium, reflects on the challenge of naming variants of SARS-CoV-2
Many of us have at some stage in our lives played a memory game, where we look at a tray of physical items and then try to remember them after the tray is hidden from sight. The human brain seems to be wired to remember everyday items such as a hairdryer, comb, cup, glove, grape, glass, ring or photo. The same game can be repeated with a list of words, where we might remember these through mental association with the meaning of the word. For example, the word ‘ring’ might lead us to think about our own jewellery or even look at a ring we are wearing. Some people go to great lengths to train themselves to remember long lists of items or words.
But the majority of people would struggle to remember a list of apparently unrelated numbers, letters, or worse still, a mixture of numbers and letters. Some number combinations are special to us, such birth dates and calendar events of special significance. A minority of people have synaesthesia, when letters or numbers may be perceived as colours, which may help in recall. But for most of us, we are unable to remember number series without looking them up – even if these are particular to us. For example, I don’t know my 12-digit credit card number or NHS number.
The challenge of naming SARS-CoV-2 variants
And therein lies the problem that we are facing with communicating about COVID-19. The SARS-CoV-2 virus is constantly evolving to generate new variants, and some of these are going to become important because of a change in their biological property. We worry most about changes in virus transmissibility, severity of disease, immunity (from ‘natural’ infection or after being vaccinated), and the way that some diagnostic tests for COVID-19 perform. This needs to be communicated effectively to all of us so that we can understand why scientists and governments become concerned, and why they make changes in policy that affect the way we live.
The scale of the task ahead in naming variants is difficult to judge. Currently, there are only a handful of variants that are being tracked globally because of possible changes in the way they interact with humans. But already the terminology is complex. For example, the variant first detected in the UK that is more transmissible is referred to as lineage B.1.1.7; as 20B/501Y.V1; and is also termed Variant of Concern 202012/01 (year 2020, month 12, variant 01) by Public Health England. A second variant first detected in South Africa is referred to as lineage B1.351, the 501.V2 variant; 20C/501Y.V2, and Variant of Concern 202012/02.
There is good reason to think that understanding variant names and what they mean is about to get much more challenging, not least because the SARS-CoV-2 virus makes around one or two mutations (mistakes) a month as it makes copies of itself on its passage through the human population. That sounds like quite a low number, and the mutation rate for SARS-CoV-2 is lower than for other viruses, including influenza. But there is an important difference. The more that the virus circulates, the more opportunity it has to change. And with more than 97 million cases of COVID-19 globally to date (a huge number but an underestimate of the true count because of asymptomatic infection), this represents a great deal of opportunity for viral mutations to occur. Unless mutations prove harmful to the virus itself (for example, making the virus less transmissible than other variants in circulation), these are carried into future generations.
The WHO are working on a standardized global system for naming new variants of concern. This is vital and will help the scientific community to accurately communicate.
But the question is – will this help me to explain the situation to family, friends and neighbours, and help how they communicate between themselves?
Searching for simple ways to rapidly convey numerical information has been done many times before. Perhaps the most obvious example is giving names to tropical storms. This dates back to 1953 and was introduced to help their quick identification in warning messages. Names were considered easier to remember than precise position coordinates (latitude and longitude). Names are also easy to communicate in the media and this approach has proved to be less error prone. An added advantage is that it is possible to differentiate between several storms that are occurring at the same time. For example, Tropical Storm Laura and Tropical Storm Marco were tracked in the U.S. as they headed towards the Gulf Coast in Aug 2020. This is just one solution of many that could be applied to viral variants.
There are other problems with the way that we use language to describe variants.
It is a worrying trend that we link variants to the country where they were first detected. For example, use of the terms ‘South African variant’, ‘Brazilian Variant’ or ‘British variant’ are frequent, but they are unhelpful for several reasons.
This language is wittingly or unwittingly linked with blame. Yet we know that virus evolution is a fact of nature, and governments cannot be held responsible for the emergence of a viral variant with a specific set of mutations. Decisions such as when to lockdown, how stringent this is, and travel and quarantine restrictions will all have a bearing on in-country transmission and onward spread of a variant, but an act of nature should not be attributed to a single country. Furthermore, it is only a matter of time before an increasing number of countries identify important variants that have emerged on their own doorstep, and we should halt the use of country labels to stop the risk of stigmatising based on geography.
It is also unfair because countries that do the bulk of viral sequencing are also likely to find the largest number of new variants, whilst those who are not sequencing will find none. For example, the UK generates just under half of the global genome total and are likely to find more variants than other countries. It is vital that we continue to sequence the virus since this is making a significant contribution to our global understanding of COVID-19. But countries who are actively sequencing should not be penalised as a result. Worse still, the narrative needs to change to avoid introducing a perverse disincentive for countries who are thinking about increasing their sequencing efforts.
There is another narrative emerging that could also be associated with stigma. Some people want to know the identity of the first person who had COVID-19 with a particular variant. Knowing the first known index case could lead to stigmatisation of individuals or even groups of people. It is already suspected that people with weakened immune systems who develop COVID-19 and who can have the virus in their body for a prolonged period of time may represent a circumstance in which the virus could accumulate multiple mutations. But this is for scientific study to determine and cannot be judged based on single cases. It is also close to impossible to be certain that no other cases of COVID-19 with that variant have occurred, because we do not detect everyone with COVID-19 (such as those with no symptoms), and we cannot sequence all viruses.
Formal names for viral variants of SARS-CoV-2 are going to prove essential for the scientific community, and the WHO will establish this through careful consultation. But for non-scientists, a memorable name that can be associated with the reason why a variant is being monitored and controlled would help us all. The ingenuity of the human imagination is likely to come to our rescue – but this needs to happen soon.