Almost two years into the Covid-19 pandemic, yet still no sight of light at the end of the tunnel, right? From washing food item packets every time we bought it, to planning a trip amidst the pandemic when the curve goes down, we have almost grown in this span, be it being habituated about the situation or being open to more possibilities in the future. But what exactly is keeping this pandemic alive, and cases surge time and again? Well, new virus mutation might be one of the causes.
What is virus mutation?
A virus is an infectious agent that can multiply only when inside living cells of an organism i.e., host cells. When not inside any organism, viruses exist as independent particles or virions. Most of the viral diseases are contagious and viruses’ transmission can occur in many ways like from plant to plant through vectors (living organisms who transmits infectious agent from an infected animal to animal or human), insects in animals, respiratory droplets (mucus or spit) suspended in air transmitting virus among human beings, contact transmission, etc.
Virus mutation means genetic changes, i.e., genetic copying errors that can lead to change in its surface proteins or antigens. Mutation can help the virus adapt better to its surrounding, multiply faster or attach to the surface of human cells more effectively i.e., bind better to receptors on human cells and sometimes, become more infectious. Our immune system uses these antigens to recognize and fight the virus, and mutation alters these antigens as commonly called “antigenic drift”, making the surface of the mutated virus different from the surface of the original virus.
Thus, mutations give rise to new virus variants, that can be more dangerous than their parent if they have traits to better evade the body’s immune system. Genome sequencing or genomic surveillance, a method where researchers sequence the genetic material of pathogens to identify changes linked to the roots of the disease, helps track new viral mutations, and to study if any newer, more transmissible variants occur. No wonder, ever since the pandemic started, we came across names of different variants in different parts of the world, each one claimed to be more contagious than the other.
The variants are categorized as
- Variants being monitored (VBM)
- Variants of Interests (VOI)
- Variants of Concern (VOC)
- Variants of High consequence (VOHC)
Major Novel Coronavirus Variants
1. Alpha (B.1.1.7)
First detected in November 2020, from a sample collected in the United Kingdom in September.
According to scientists, this variant of SARS-CoV-2 caused by a mutation in the virus’ spike protein, was found to be 70% more transmissible than the original virus, along with claims of it having a higher risk factor for covid deaths (around 1.6 times higher). The alpha variant has been found to have seventeen mutations compared to its original virus (SARS-CoV-2) making it multiply and infect faster. Symptoms of the alpha variant are cough, fever, headache, loss of appetite, muscle ache, and a few reports of anosmia or loss in sense of smell or taste. Detection of this variant can be done through RNA sequencing, and RT-PCR tests for other specific variants can sometimes be used as well.
2. Beta (B.1.351)
First detected in October 2020 in South Africa and reported on 18 December 2020, by South Africa’s health department.
Scientists reported the variant to be mutated to attach better with the human cells due to three mutations in the receptor-binding domain in the spike protein of the virus. The beta variant also contains E484K mutation that helps the virus partially evade antibodies i.e., the body’s immune system. The variant was reported in approximately 123 countries and was declared a variant of concern by WHO, but is no longer a dominant variant. Symptoms are similar to other Covid variants and are identified through genome sequencing.
3. Gamma (P.1)
First detected by the National Institute of Infectious Diseases of Japan on 6th January 2021 in 4 people in Tokyo, who had visited Amazonas, Brazil four days prior, and reported publicly on 10th January 2021.
Similar E484K mutation was detected, along with several other mutations in the receptor-binding domain of spike protein. The variant was found to be 2.5 times more contagious than the original SARS-CoV-2 virus. The variant caused widespread infection in the city of Manaus, Amazonas in early 2021, and was later reported in more than 70 countries.
4. Delta (B.1.617.2)
First detected in India in October 2020, and was named on 31st May 2020.
The variant was partly behind India’s deadly second wave in May which witnessed a rapid surge in infections, hospitalization, deaths and was also behind the third wave in Fiji, the United Kingdom, and South Africa. World Health Organization reported in June 2021 that the delta variant was becoming a dominant strain globally. It was mutated to be highly transmissible, about 40%-60% more than the Alpha variant, with a high risk of hospitalization. Most reported symptoms were runny nose, sore throat, headache, and increased complaints of breathlessness while infected.
5. Mu (B.1.621)
First identified in January 2021, in Colombia.
The global occurrence of the variant remains at less than 0.1% though it is reported to be increasing steadily in Colombia and Ecuador. It is labeled as a variant of interest by WHO, and not a variant of concern till now. It has been found in around 43 countries and no specific symptoms related to the variant have been reported.
First identified in Japan and detected in late 2020.
Later, in March 2021, an outbreak was reported in a Kentucky nursing home when 45 residents and health care personnel were infected with R.1 variant. Symptoms remain similar to the other variants. The WHO labeled it a variant being monitored in April 2021 i.e., it might act as a future risk but is currently not a variant of concern or variant of interest.
7. Omicron (B.1.1.529)
First reported to the WHO (World Health Organization) on 24th November 2021, from South Africa.
The WHO has named omicron as a variant of concern as the transmissibility of the omicron variant is more than the original SARS-CoV-2 virus, and anyone infected can spread the disease, even if they are vaccinated or not. The omicron variant is feared to be less likely to respond to vaccines and existing treatments and runs a higher risk of reinfection as per evidence till now. The omicron variant is now the dominant variant in the U.S and has been detected in 106 countries as of 22 December 2021.
There are still uncertainties about the risks of hospitalization of this variant compared to the delta variant and the recent spike in covid deaths and a new surge in cases leaves a room full of possibilities that are yet to be known for sure. The symptoms are similar to covid, like sore throat, runny nose, and headache including cough, fatigue, and congestion, and can appear from 2 to 14 days after the infected person is exposed to the virus. Detection of omicron can be done through analysis of swabs from PCR tests in the lab.
Other notable covid-19 variants include Epsilon, Theta, Zeta, Lambda, and IHU.
Taking precautions and following safety protocols
Virus mutation may lead to the occurrence of more variants in the future or the outbreak of any existing variants, as we find out more about them. The best we can do right now is to be cautious and follow safety protocols provided by the government, like wearing masks and using sanitizers while in public places. Maintaining required cleanliness, a safe distance from others, and being vaccinated on time will also contribute towards our fight against the pandemic, whose future remains uncertain to all.