Covid-19: Understanding Mutations and Delta Variants

By Rajneesh Bhandari

The pandemic added words like “spike protein, delta variant, mutation, etc.” to our household vocabulary, and now we have a new phrase “Delta plus” on the horizon.

A mutation is a change in the genome sequence of an organism. Mutations can result from genetic “copying errors” in the replication of the organism, exposure to ionizing radiation, exposure to certain chemicals, etc. Mutations cause new variations in a species, and cumulative mutations can even lead to the emergence of new species. For example, chimpanzee-like animals evolved into humans over millions of years through a series of mutations. Mutations arise purely by chance and can be desirable or undesirable for the organism. A mutation that helps the organism adapt better to the environment is passed on to the next generation, and organisms with unwanted mutations have a lower chance of survival. Charles Darwin described this process as “Natural Selection” in his seminal work “On the Origin of Species” in the 19th century.

New infectious diseases occur mainly as a result of random mutations in virus / bacterial genomes. These mutations allow the virus to pass from animals to humans, overcome the human immune system, or even become resistant to antibiotics. The high mutation rates in viruses, coupled with short replication times and large numbers, enable viruses to develop quickly and adapt to the host environment. It’s interesting to understand that the virus doesn’t mutate to escape a vaccine or drug, or to become more contagious. Instead, mutations are random copy errors that happen randomly. Random mutations that allow a virus to survive better are passed on to the next generation as the virus reproduces. Many of these mutations are insignificant and have no effect on the rate of spread or the severity of the infection. Some mutations could even make the virus less contagious.

The influenza virus is a great example of how viruses change, causing the virus to escape natural immunity or vaccine-induced immunity. Our immune system uses surface proteins (such as the “spike protein”) from the virus to recognize the virus and make antibodies against the virus. Genetic mutations in influenza viruses can alter their surface proteins, making the surface of a mutated virus look different from the original virus. In this case, the body’s immunity to previous flu infections will no longer work against the new strains. A person then becomes susceptible to the newer, mutated flu viruses. The old vaccines don’t offer immunity either. Because of this, flu vaccines need to be updated every year to keep up with the changing influenza virus.

The Covid virus mutates relatively slowly compared to other RNA viruses. This is due to its ability to “proofread” newly created RNA copies of itself. This “proofreading” feature does not exist with most other RNA viruses, including influenza. Therefore, if the Covid virus continues to mutate at a relatively slow rate of mutation, the vaccines will last longer.

Pfizer and Moderna’s vaccines used a novel mRNA technology that does not require a weakened or dead virus for the vaccine. The mRNA technology only needs the genetic sequence (code) of the coronavirus to produce the vaccine; no live virus needs to be cultivated and grown in the laboratory. This new technology is like writing a software upgrade instead of finding new hardware every time. The mRNA technology platform can modify and optimize vaccines to adapt to new variants faster than traditional vaccines. Similarly, the yet to be launched Zydus Cadila DNA vaccine will be able to easily upgrade the vaccine for new variants that may emerge in the future.

The Delta variant was mainly responsible for the second wave of coronavirus infections and was first identified in India. It is now the dominant strain 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) due to its significantly higher transferability.

A study conducted by Public Health England (PHE) found that the Pfizer and AstraZeneca (Covishield) vaccines provided 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. In the UK, new cases are increasing every day, especially among the younger unvaccinated and partially vaccinated populations.

A new variant, Delta Plus, was recently identified. Experts believe Delta Plus doesn’t appear to be any more contagious than Delta. It’s too early to say whether this additional mutation in the Delta variant increases mortality or makes the vaccine less effective.

The more people infected with the virus, the greater the chance of random mutations. There is a risk that one of these random mutations could turn out to be an “escape mutation,” which allows the virus to slip past the natural antibodies that are present due to previous infections and existing vaccines. The faster we carry out a universal vaccination, the more we can reduce the chance of an “escape mutation”. It’s like getting a royal flush in poker. While the chances of getting a royal flush are extremely slim, when millions of people are playing poker online, some random person may get a royal flush somewhere on the internet every day.

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