Since the outbreak of the coronavirus pandemic last spring, we’ve had to speed up dozens of new terms in our vocabulary. Over the past few weeks, we have been hearing nonstop – and with increasing concern from experts – the words strain, variant, or mutation. Can they be used interchangeably? The short answer: no, the distinction is important.
We describe it below:
Mutation
This term refers to the changes viruses undergo at the genetic level. While the word mutation may sound threatening, viruses constantly mutate naturally and make small changes to their genetic material when they replicate.
Some viruses mutate faster than others. The flu, for example, mutates very quickly.
variant
Different mutations are grouped into variants, as it were. The three best-known variants are those of UK (the technical name is B.1.1.7, which contains 23 mutations compared to the original virus), the one from South Africa (501Y.V2, which shares some mutations with that of the United Kingdom) and the variant that comes from Brazil (P.1.), which, according to the U.S. Centers for Disease Control and Prevention (CDC) contains a series of mutations that can affect antibody recognition.
These three variants are already present in the US and experts believe that the British variant, which spreads faster and could be more deadly, could become dominant in the US in March.
A variant is therefore a virus that mutates time and again.
Sieve
When a virus has had a drastic mutation in its genetic order, a strain appears. For the time being, this has not happened with the corona virus.
SARS-CoV-2 is one of several strains of coronaviruses. The two most well-known types or strains of coronavirus to date are SARS-CoV-2, which appeared in Wuhan, China in late 2019, and SARS-CoV-1, which appeared in China in 2004, which causes severe acute respiratory syndrome.
It is imprecise to say that the UK registered variety is a new species. For that to happen, the virus would have to undergo a drastic change or mutation in its gene chain, which has not happened so far. For this reason, it is still being considered the vaccines developed so far are effective against the virus.
Ian Jones, professor of virology at the University of Reading in the UK, notes that the most appropriate term to describe new forms of COVID-19, such as those in the UK and South Africa, is ‘variant’. The difference between a strain and a variant “is a matter of the degree of change, but there is no magic level (sometimes 10% is generally used) so there is some uncertainty about it,” he said in statements to Newsweek.
