COVID-19 Day 38: The Mutant Threat Is Overblown

C19_mutations

An article in the South China Morning Post, raises the alarm that a new virus mutation might make the development of a COVID-19 vaccine impossible. This mutated SARS-CoV-2 virus (SARS2) has a differently shaped protein spike in its shell. This means the virus may be less likely to bind to the ACE2 (Angiotensin Converting Enzyme-2) binding site found in lung and throat cells. Vaccine researchers around the world are currently working to replicate the ACE2 binding spike in SARS2 in order to create a working COVID-19 vaccine.

The article implies that an ACE2 mutation could make an ACE2 spike-based vaccine infective. This all the more alarming because the mutant virus was identified in a patient in India, which has a population of over 1.3 billion people. A vaccine-resistant strain there could be catastrophic. But the alarm may be overblown (as news reports often are.)

The same SARS2 mutation that makes an ACE2 vaccine less likely to effective against the virus also makes the virus less able to infect cells or individuals. This is evidenced by the rarity of this mutation (it was only identified in one patient sample). In all likelihood, this mutant Indian strain appeared and died out; out-competed by the “main strains” of SARS2.

Multiple strains of SARS2 are circulating the world at this moment. This has helped researchers to track the route the pandemic has taken after it escaped Wuhan. Each strain is a mutation but most are less effective than the 2 main strains that are creating the pandemic. 

In the Singapore outbreak, their SARS2 strain was identified by a missing gene sequence normally found in the worldwide (Wuhan) strain. It is speculated that this mutation made the Singapore strain less infectious, helping Singapore to quickly end the epidemic in their country.

In fact, the 2 main strains of SARS2 are thought to produce different symptoms and illnesses in people. One strain is associated with milder illness, the other with severe illness. Fortunately for us, all of these strains are similar enough that our immune systems are able to grant us immunity from other strains once we have recovered from one of them.

Dozens more strains have been identified by various research labs around the world but these strains have disappeared, the implications are that these mutations appeared and just as quickly died out because they were outcompeted by the more successful strains. That’s natural selection working in real-time. 

Random mutations happen in cells and organisms all the time. It’s part of the messy process that we call life. Unlike the X-Men, mutations don’t give viruses super-powers that can’t eventually be overcome. This may be cold comfort for all of us dealing with COVID-19 hype. But as they say in another popular comic book, “knowing is half the battle.”

 


SOURCES

https://www.biorxiv.org/content/10.1101/2020.03.11.987222v1

https://www.microbe.tv/twiv/twiv-601/?fbclid=IwAR0MPyLlO1_LWJdD0tWg1adDFdcEs-MUZsHbckpJh8Bg4a4n2r5DYAO28ps

https://www.ncbi.nlm.nih.gov/pubmed/30310104

https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540747/all/Coronavirus_COVID_19__SARS_CoV_2_

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