CoronaVirus: The Biological Mystique
Written by Akshita Poddar
Illustrated by Urvi Agarwal
Edited by Anvita Tripathi
Viruses are constantly mutating and producing different versions or variants. Most of these mutations are insignificant and some can make the virus even less dangerous, but others can make it all the more contagious and make vaccination almost impossible. The global situation of COVID-19 is so dynamic because of the variants that have been and are being circulated at this very moment in our very own countries. The different variants have spread to more than eighty countries and the virus shall continue to mutate as it spreads across the globe. To dig deeper into this, Perspectiverse’s Akshita Poddar brings to you, CoronaVirus: The Biological Mystique.
The ‘Alpha’ Variant
There are quite a few variants or mutations of covid but only a few have been either labeled as ‘variants of interest’ (VoI) or ‘variants of concern’(VoC). Alpha is one of them. The Alpha variant emerged in England in September 2020 and drove a winter surge in cases that sent the U.K. back into lockdown in January. Other countries, particularly in Europe, followed the U.K. in reimposing movement restrictions. Alpha became the dominant strain in the U.S. in early April and has been reported in at least 172 countries, according to the WHO. It has a 50% increased transmission rate and has a potential increased severity based on hospitalizations and case fatality rates. It has no impact on susceptibility to EUA monoclonal antibody treatments and has a minimal impact on neutralization by convalescent and post-vaccination sera.
The ‘Beta’ Variant
The beta variant appeared in South Africa in August 2020, and led to a resurgence in Covid cases that overwhelmed southern Africa. It’s been reported in at least 120 countries. It has a 50% increased transmission and has also significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment. It has reduced neutralization by convalescent and post-vaccination sera. Researchers and officials reported that the prevalence of the variant was higher among young people with no underlying health conditions, and more frequently causes serious illness in such cases than other variants. The South African health department also indicated that the variant may be driving the second wave of the Covid- 19 pandemic in the country, as the variant spreads faster than other earlier variants of the virus.
The ‘Gamma’ Variant
Gamma was the variant which was first spotted in the Amazon city of Manaus in December 2020, and has since contributed to a surge in cases that strained Brazil’s health system and led to oxygen shortages. It’s been reported in at least 72 countries since then and has Increased transmissibility and potential reduction in neutralization by some EUA monoclonal antibody treatments and by post vaccination sera.
The ‘Delta’ Variant
Delta is a fast-spreading variant that stoked a dramatic wave of Covid cases in India that overwhelmed hospitals and crematoriums and has since been found in at least 96 countries. It’s estimated to be 60% more transmissible than alpha and has reduced neutralization by convalescent and post-vaccination sera. Doctors in India have linked delta to a broader array of Covid symptoms, including hearing impairment, and in June, data from both England and Scotland suggested an increased risk of hospitalization compared to alpha. Other evidence found delta had some propensity to evade antibody-based treatments and that it potentially increased the risk of reinfection in people who have recovered from Covid caused by another strain. It significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment, but other EUA monoclonal antibody treatments are available.
The ‘Delta Plus’ Variant
As if the Delta variant was not worrisome and concerning enough that there is Delta Plus now as well. Delta Plus is the latest variant of SARS-CoV-2 and was announced in late June by Indian health officials and labelled by the Indian government as a variant of concern. The variant was first seen in Europe in March this year. It was, however, brought into the public domain only on June 13. concerns have been rightly raised regarding Delta Plus, considering the original Delta strain’s ability to transmit more efficiently from person to person, and to potentially cause more severe disease. Delta Plus contains an additional mutation called K417N, in the part of the spike protein of the virus that binds to cells to start infection. There are concerns regarding Delta Plus that this mutation alone may not lead to a third wave in India but could definitely be one of the reasons that fuel the third wave. There are worries Delta Plus would inflict another wave of infections on India after it emerged from the world’s worst surge in cases only recently. The prevalence of this new variant is still low in India, data shows. Delta remains the dominant variant in the country as of now.
Apart from Maharashtra, the other states reportedly seeing Delta Plus cases include Tamil Nadu, Kerala, Punjab and Madhya Pradesh so far. As of June 16, at least 197 cases had been found from 11 countries — Britain, Canada, India, Japan, Nepal, Poland, Portugal, Russia, Switzerland, Turkey, and the United States. When the delta variant develops additional mutations of possible importance, it is called delta plus. As of now, the K417N mutation, which was previously seen in the Beta variant, is what people usually mean when they say delta plus. This is not a delta/Beta hybrid, but a case of convergent evolution where mutations develop independently.
The Delta Plus mutation is worrying because it’s located on a key portion of the virus, the spike protein, used to penetrate human cells. Previous mutations have been identified on the “receptor binding domain” of the spike protein that allows the virus to attach to the receptors in our cells.
The unique mutations in the Delta variant mean the virus can escape the immune system to some extent. Delta has shown to reduce the efficacy of vaccines somewhat. This means a single dose of vaccine may offer reduced protection. However, a second dose has been shown to produce enough antibodies against symptomatic infection and severe disease. But then again, it is also important to remember that most COVID vaccines don’t provide absolute sterilising immunity, but work to reduce the severity of disease.
British researchers found that the effectiveness of the Pfizer vaccine in Delta after a single injection was 33% and reached 88% after two injections. For the AstraZeneca vaccine, the first dose is only 33% effective, but the second dose is 60%. Delta plus variants may have a similar degree of reduction in efficacy to currently used vaccines. Although solid or good data is yet to be seen on whether this is the case. Studies have been said to be under way in India to assess the effectiveness of vaccines against Delta plus.