‘Delta Variants’ of the Coronavirus: Poses New Threat to Covid-infection Spread

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Juni Banerjee, PhD; June 29,2021

A newer addition to the corona-infection threat throughout the world has recently come from the Delta variant of the coronavirus. Scientists are referring to this variant as B1817.2. First identified in December 2020 from India, the Delta variant has been able to spread quite a significant infection and create newer Covid cases i.e., by April 2021. Since then, the WHO (World Health Organization) reported the presence of this variant from 80 more countries (e.g., Britain, America, Africa, Israel, etc) around the globe. B1617.2 has been already declared as the ‘Variant of Concern’ in Europe. The fact that the Delta variant is capable of spreading more infections than the other variants of the Corona has made scientists, physicians, and even the general public worried. Several questions have been popping into our minds like a) how serious is this variant with regards to transmissibility b) what are the symptoms of Delta virus infection c) can the existing vaccines prevent Delta variant infections, etc. In this article, we will address all such queries about the Delta variants of Coronavirus.

How infectious are these Delta variants?

As of June 2021, the Delta variant has already spread to 64 countries around the world. This variant has caused more infections than the Alpha variant discovered in Britain. According to scientists, the Delta variant is about 43% -90% more contagious than the alpha variant! UK data showed that the Delta variant is about 60% more transmissible than the alpha variant (previously called B.1.1.7). Research so far has also indicated that the number of hospital admissions after being infected by the Delta variant is almost double that of the Alpha variant! While these figures still needed more research validations to reach a definitive conclusion. 

Is the Delta variant more of a risk to any certain age group of people?

According to the Scientists, the Delta variant will infect children and middle-aged people more! This prediction has been made on the basis of data from Britain that showed about 2.5 times more infections among the young people by the Delta variant as compared to the normal variant.

Can the symptoms of the Delta variant infection be differentiated?

The symptoms of the Delta variant are slightly different from the general symptoms of the Covid-19. This variant is capable of showing symptoms like cold, sore throat, fever, headache and might confuse it with common cold or influenza. Of note, there has been an official change about the Covid-19 symptoms provided by the UK’s National Health Service (NHS) that previously listed fever, continuous cough, and loss of smell or taste as the primary symptoms of Covid-19 illness. Scientists fear that the infection from Delta variants might spread more if it doesn’t get diagnosed at the right time.

What are the significant mutations found in the Delta variants?

It has been found that the delta variant has 2 important sets of mutations in its spike protein of which one is at the furin cleavage site, which is probably the crucial one for the fitness of the virus in the airway.


What about the “Delta Plus Variant” and does it pose similar threats?

In India, a special mutant variant called the Delta Plus variant (AY-1) has been found during the second wave infection. According to the Indian Ministry of Health, the Delta Plus variant has spread to Kerala, Maharashtra, and Madhya Pradesh. However, there are reports of this mutant Delta Plus variant infection from different countries of the world, such as America, Portugal, Poland, Russia, Japan, China, etc too. 

Interestingly, an additional mutation called “K417N” has been observed in the spike protein of this Delta Plus variant. This mutation is located at the furin cleavage site of the protein. Studies have shown that this Delta Plus variant can easily infect the lung cells and, more importantly, can develop resistance to monoclonal antibody treatment!  However, fewer research data so far has not yet made it clear if the transmission capacity of the Delta Plus variant has increased due to the K417N mutation. However, Dr. Kamil from India reported that “Delta plus might have a slight advantage at infecting and spreading between people who were previously infected earlier during the pandemic or who have weak or incomplete vaccine immunity”.

Are the Delta variants vaccine-resistant? 

At this moment, high vaccination rates can help to fight coronavirus and its variants. In other words, the risks to see Delta- and Delta plus-variants outbreaks could be places with lower vaccination rates. 

The researchers found that the two-dose mRNA vaccine (Pfizer-BioeNtech and Moderna) is highly effective i.e. about 79-88% resistance to Delta variant infection. Among other vaccines, around 92% of the Delta variant patients who received the Covishield vaccine did not have to be hospitalized for Covid-19-induced illness. In addition, the viral vector vaccines from Johnson & Johnson and AstraZeneca have been found to be 60% effective against the Delta variants. After testing a limited number of patients and without complete peer-reviewed data, Bharat Biotech has claimed that their developed ‘Covaxin’ is capable of preventing infection by the Delta variant. Russia’s Sputnik-V manufacturer also claims the same about Sputnik. 

Although more research and clinical data are required soon to get the whole scenario about the Delta variants, the best tools to prevent its infections are getting proper vaccinations, using N-99 or N-95 masks, and following the rules of hygiene at the workplace even at the home.


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