The outbreak of Delta Plus variant: The notorious and novel strain of SARS-CoV-2

The first appearance of COVID-19 from Wuhan, China, has now showed up with changed variants, resulting in millions of fatalities, billions of job losses, and remarkable economic damage by spreading across the world. It has been consistently evolved into more severe categories with its newfangled and fast-spreading mutant variants while entering its second year. Among its eleven variants (Alpha, Beta, Gamma, Delta, Delta Plus, Epsilon, Eta, Theta, Iota, Kappa, and Lambda), recently Delta Plus variant is becoming the dominant version of this pandemic right after Delta variant.^, On 22nd September, three cases of this variant in Mizoram, India has been reported. From the Maharashtra, Kerala and Madhya Pradesh states, India, it is about to invade neighboring states and has been outspread to overseas like the USA, Canada, UK, Russia, Japan, Portugal, Poland, Turkey, Nepal and Switzerland. The number of infections by the Delta Plus variant in these cases is less, but it is viable enough to trigger the 3rd wave of COVID-19 in near future. Public Health England on its June 11 bulletin reported first about Delta plus variant with its six genomes from India as of June 7. It has been identified as B.1.617.2.1, or AY.1/2 which is a mutated type of more aggressive B.1.617.2, or ‘Delta’ variant with black fungus. Between these two types (“AY.1” and “AY.2”) of Delta Plus variant, “AY.1″ has been spread worldwide, whereas “AY.2″ is the dominant category in the United States and has been detected 150 times. K417 N mutation on the SARS-CoV-2 spike protein was developed by AY.1 strain which interacts with the ACE2 receptor causing the invasion of human cells. Within the Delta and Delta Plus variants, scientists discovered a total of 656 and 269 specific alterations, respectively. A total of five critical alterations (A222V, T95I, R158G, G142D, and K417 N) have been reported as more common in the Delta Plus than in the Delta version. Besides, the presence of V70F and W258L spike protein alterations (at 52% and 39%, respectively), prevalent only in the Delta plus variant also distinguishes it from the Delta variant. Moreover, in Delta Plus and Delta variant, A222V was 58% and only 9%, respectively while the prevalence of T95I mutation is 37% and 22% in Delta Plus and Delta variant respectively. According to some reports, Delta Plus, the latest variant has exerted a higher affinity for the mucosal lining of the lungs than all other previously reported variants. According to INSACOG, the AY.1 strain demonstrated higher transmissibility, better binding affinity to receptors of the lungs’ mucosal linings along with a potentially lower response to anti-COVID-19 monoclonal antibodies including Imdevimab, Casirivimab etc. As a result, it can be assumed to be less susceptible to the current vaccination program and/or therapeutical interventions.^, Prior studies on the Beta type revealed that mutations on K417 position aided in the dodging of antibody and so, K417 mutation on Delta Plus variant can also exert similar outcomes, such as evading vaccines and antibodies. In addition, the vaccination program in India with the BBV152 (Covaxin) has failed to exhibit promising outcomes against the Delta Plus variant. However, according to a Washington Post investigation, the Delta Plus variant affects the younger people most, though the preliminary researches have also revealed that antibodies from vaccinated people were still effective against this variant. To recapitulate, as a novel strain, the Delta Plus variant demands extensive research and exploration for the discovery and development of advanced therapeutics to fight against this notorious pandemic.