Covid-19: Understanding mutations and delta variants

The more people infected with the virus, the greater the chance of a random mutation.

by Rajneesh Bhandari

Pandemic has added terms like “spike protein, delta variant, mutation etc”. to our household vocabulary, and now we have a new phrase, “delta plus,” on the horizon.

Mutation is a change in the genome sequence of an organism. Mutations can result from genetic “copying errors” that occur when the organism replicates, exposure to ionizing radiation, exposure to certain chemicals, etc. Mutations cause new changes in a species, and cumulative mutations can also lead to the formation of new species. For example, animals such as chimpanzees evolved into humans due to a series of mutations over millions of years. Mutations arise purely by chance and may be desirable or undesirable for the organism. A mutation that helps the organism to adapt better to the environment is passed on to the next generation, and organisms with the unwanted mutation are less likely to survive. Charles Darwin described this process as “natural selection” in his pioneering work “On the Origin of Species” in the 19th century.

New infectious diseases mainly appear as a result of coincidental mutation of virus/bacteria genomes. These mutations allow the virus to jump from animals to humans, overcome the human immune system, or even become resistant to antibiotics. Viruses have high mutation rates, along with short replication times and large numbers, allowing the virus to evolve rapidly and adapt to the host environment. It is interesting to understand that the virus does not plan to mutate to escape a vaccine or drug or to be more contagious. Instead, mutations are random copying errors that occur by chance. Random mutations that allow a virus to survive optimally are passed on to the next generation as the virus multiplies. Many of these mutations are insignificant and do not affect the speed or severity of the spread of infection. Some mutations can also make the virus less infectious.

Influenza viruses are a classic example of how viruses mutate, causing the virus to evade natural immunity or vaccine-induced immunity. Our immune system uses surface proteins (such as “spike proteins”) of the virus to recognize the virus and make antibodies against the virus. Genetic mutations in influenza viruses can alter their surface proteins, causing the surface of the mutated virus to appear different from that of the parent virus. When this happens, the body’s immunity from a previous influenza infection no longer works against the new strains. A person then becomes vulnerable to the new, mutated flu virus. Even older vaccines do not confer immunity. This is why flu vaccines must be updated every year to keep up with the influenza virus as it changes.

The COVID virus mutates relatively slowly compared to other RNA viruses. This is due to its ability to “proofread” newly generated RNA copies of itself. This “proofreading” function is not present in most other RNA viruses, including influenza. Therefore, if the COVID virus continues to mutate at a relatively slow mutation rate, the vaccine will be effective for a long time.

Pfizer and Moderna Vaccines use a new mRNA technology that does not require a weakened or dead virus for the vaccine. mRNA technology only requires the genetic sequence (code) of the coronavirus to make a vaccine; No live virus needs to be cultured and grown in laboratories. This new technology is like writing a software upgrade instead of finding new hardware every time. The mRNA technology platform can transform and adapt vaccines to new forms faster than conventional vaccines. Similarly, the yet-to-be-launched Zydus Cadila DNA vaccine will enable the vaccine to be easily upgraded for new variants that may emerge in the future.

The delta variant was primarily responsible for driving the second wave of coronavirus infections and was first identified in India. It has now become a major tension in the UK and many other parts of the world. The World Health Organization (WHO) has classified the delta variant as a variant of concern (VOC) because of its significantly higher transmissibility.

A study conducted by Public Health England (PHE) found that the Pfizer and AstraZeneca (Covishield) vaccines provide only 33% protection against the delta variant after the first dose. Two weeks after the second dose, the Pfizer vaccine was 88% effective against the delta variant, and the AstraZeneca vaccine was 60% effective against the variant. Daily new cases are increasing in the UK, mainly in the young unvaccinated and partially vaccinated population.

A new variant, Delta Plus, has recently been identified. Experts agree that Delta Plus doesn’t seem to be more contagious than Delta. It is too early to tell whether this additional mutation in the delta variant increases mortality or reduces vaccine efficacy.

The more people infected with the virus, the greater the chance of a random mutation. There is a risk that one of these random mutations could be an “escape mutation,” which allows the virus to overtake the natural antibodies present due to previous infections and current vaccines. Thus the faster we do universal vaccination, the more we can reduce the chance of an “escape mutation”. It’s like getting a “royal flush” in a game of poker. Although the chances of getting a “Royal Flush” are very low, if there are millions of people playing poker online, some random person might get a “Royal Flush” every day somewhere on the Internet.

(The author is the founder of NeuroEquilibrium and Think Healthcare. Views expressed are personal and do not reflect the official position or policy of Financial Express Online.)