Since last year, the world is going through the Covid-19 pandemic and many variants of the original SARS COV 2 virus are emerging frequently. These variants are appearing to be more transmissible, more contagious, and causing global threats, even to immunized people as the vaccines are reported to be less effective against these multiple variants of coronavirus.
The evolution of variants of coronavirus
All viruses change through mutations. The virus replicates itself by hijacking the biological machinery of the host cells. The genetic replication process is often met with random errors, leading to genetic mutations. Most genetic changes do not affect the properties of a virus. However, sometimes genetic errors may randomly lead to advantageous changes in the properties of the virus. These changes may affect the public health and disease transmission parameters if the mutations facilitate host cell entry, enable the production of more copies, evade the host immune responses or, cause more severe disease symptoms. For example, flu viruses change often, hence, doctors recommend that people should take new flu shots every year.
The SARS-CoV-2 virus (which originally caused COVID19) is not an exception either. It has been constantly evolving and a pile of changes can be seen over time in form of several variants. Scientists believe that geographic separation gives rise to genetically distinct variants. In the early days of the pandemic, one of such mutations made the virus more transmissible and it started infecting a larger percentage of younger people. Soon, the Covid-19 virus suffered more mutations and multiple variants of coronavirus started emerging with significant mutations which are genetically different from the original Coronavirus which was detected in China at the beginning of the Covid-19 pandemic. All the variants so far have suffered changes in their spike protein which affects the attachment to host cells.
Some of these variants are considered as variants of concern (VOC), e.g., Alpha, Beta, etc. and others are known as variants of interest (VOI), e.g., Eta, Kappa, Lambda, etc. According to WHO, a VOC means an increase in transmissibility and mortality, but, decrease ineffectiveness of vaccines and other therapeutical measures. However, a VOI is a genetically different variant that can affect disease severity, community transmission, immunological and therapeutical responses. Variants of interest (VOI) must be monitored closely until they become VOCs.
A complete list of Variants of Concern (VOC)
1. Alpha - B.1.1.7
The first variant was detected in the United Kingdom, in December 2020 and spread to more than 50 countries. It had accumulated 17 mutations which led to about a 50 % increase in its transmission and increased cases of hospitalization and death than the original Covid-19 virus. It soon became the most common cause of Coronavirus in the UK. All the currently authorized vaccines work against this variant but, some rare infections in fully vaccinated people have also been reported. Most treatments are effective against this variant.
2. Beta - B.1.351
This variant was first detected in South Africa, in December 2020 and has spread to at least 20 other countries. It spreads faster than earlier circulating variants. It has also been reported to cause re-infection in already recovered people from the earlier variants of Coronavirus. Current vaccines mostly work against this variant but, it has shown some cases of resistance to certain vaccines. Except for certain monoclonal antibody treatments, most treatments are effective against this variant.
3. Gamma - P.1
This variant was first detected in Japan/Brazil, in January 2021 and has spread to more than 10 other countries. It spreads faster than earlier variants. Current vaccines mostly work against this variant but, some rare infections n fully vaccinated people have also been reported. Except for certain monoclonal antibody treatments, most treatments are effective against this variant.
4. Delta - B.1.617.2
This variant was first detected in India, in April 2021. It spreads faster and has been reported to cause more severe cases than other variants. A small percentage of fully vaccinated people may suffer breakthrough infections. However, preliminary epidemiological studies have suggested that fully vaccinated people with or without getting infected with this variant can successfully transmit it to others. To date, it is considered the most contagious variant of SARS- CoV-2 Coronavirus. It is rapidly becoming the most dominant variant of Coronavirus in the United States and the United Kingdom this year.
Will vaccines work on new variants?
As long as Coronavirus is spreading in the population, mutations are bound to happen which may lead to several new variants of the original SARS-CoV-2 Coronavirus. Preliminary laboratory studies on immune responses of currently authorized vaccines have shown that the new variants might be more resistant to the current vaccines. However, these vaccines definitely provide a protective shield of immunity and maybe they are less effective, but they certainly cut off the risk of severe illness and death. It is possible that similar to the flu vaccine which is being updated annually according to the evolution of new variants of the flu virus, annual Corona vaccines have to be developed to deal with the emerging new variants of the SARS-CoV-2 Coronavirus.