We have begun a new year (2021) and Covid-19 is still with us.
Research has shown that the disease is caused by the SARS-CoV-2 virus, which has a genome composed of RNA (ribonucleic acid) comprising around 30,000 bases.
These bases are adenine (A), guanine (G), uracil (U) and cytosine (C).
Simply put, these genetic building blocks combine in various specific sets of three to make amino acids, which then combine to make a protein.
The spike protein present on the SARS-CoV-2 virus is made of 1,273 amino acids.
Any change in the combination can cause a change in the protein – an occurrence commonly called a mutation.
As the SARS-CoV-2 virus genome is made of single-stranded RNA, the mutation rate is slightly higher than that of bacteria, which have a double-stranded DNA (deoxyribonucleic acid) genome.
So far, several mutations have been reported in the SARS-CoV-2 virus, including the one discovered in the United Kingdom that is purportedly making the virus more infectious.
Most of the speculation about this virus variant is based on genome sequence and epidemiological data without experimental evidence, hence it is hard to conclude the actual infectivity of this variant.
Thorough biological and virological studies need to be conducted to understand this specific mutation’s role in transmission, disease severity and death.
However, there are three reasons why we should not worry about mutations in the SARS-CoV-2 virus:
Most of the vaccines that are being developed for Covid-19 are utilising the spike protein or its genes as the target for the body’s immune system.
Our immune system can only recognise and respond to epitopes – a short stretch of eight to 15 amino acids in the SARS-CoV-2 spike protein.
But with 1,273 amino acids available, there are numerous epitopes that can be targeted by our immune system.
Therefore, a mutation or change in just one amino acid in a few locations will not significantly change our immune response to a vaccine.
It is analogous to shooting an object that has 100 targets.
If we miss two targets, we still have 98 targets to “shoot” and clear the virus.
Both the Pfizer/BioNTech and Moderna vaccines are RNA-based.
The vaccine is essentially synthesised in the laboratory based on the genome sequence of the SARS-CoV-2 virus and encapsulated with lipid molecules.
In the event of major mutations in the spike protein genes, suitably-modified RNA vaccines can be easily synthesised in a lab in a very short time.
Therefore, we can draw some comfort in the fact that it is unlikely a sporadic mutation of the spike protein genes will alter the immune efficiency of forthcoming vaccines for Covid-19.
Nevertheless, we should still monitor all possible variants of this virus through genetic sequencing.
The molecular diagnostic test for Covid-19 is done via a real-time PCR (polymerase chain reaction) method to detect specific genetic sequences among the 30,000 bases.
Generally, multiple genes are targeted by this test, so even if one gene is mutated, the others can still be detected by this method.
Even if just the spike protein is used as a target, the location of the primers can be changed based on the mutations prevalent in the region.
Primers are like bookends that define the region of genes to be sequenced during PCR.
Hence, the impact on the diagnostic accuracy of the test due to possible mutations can be avoided by choosing the correct region of genes to be sequenced.
Despite any mutations, the virus can be contained if everybody strictly follows the proper standard operating procedures (SOPs).
Observing the new norms such as wearing face masks, washing hands with soap and water frequently, using hand sanitisers, maintaining physical distancing, and minimising non-essential travel, is a must.
Even if a mutation allows for faster spread of the virus, strictly following SOPs will allow for a break in the chain of transmission.
In conclusion, the mutations in the SARS-CoV-2 virus may not be as dangerous as they appear.
Let us trust the vaccines and our immunity, and strictly follow the SOPs.
Prof Dr Ravichandran Manickam is a medical microbiologist and biotechnologist currently researching Covid-19, and AIMST University Faculty of Applied Sciences dean. For more information, email email@example.com. The information provided is for educational purposes only and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
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