The Indian Ministry of Health announced last Tuesday evening (22) the discovery of a new variant called “Delta Plus” (B.1.617.2.1), which comes from the dominant variety of the Asian country called Delta (B. 1.617.2).
The new strain emerged in April and has been detected in at least 40 samples in the three Indian states of Maharashtra, Kerala and Madhya Pradesh. Of these, 16 were in Maharashtra province alone, one of the Indian regions hardest hit by the pandemic.
In addition to India, the variant has already been detected in virus samples in at least nine other countries: China, USA, Japan, Nepal, Poland, Portugal, Great Britain, Russia and Switzerland.
According to the Indian health authorities, states have been notified of cases and advised public health services to “respond with targeted and more effective health measures.” Government officials were advised to “take immediate action to curb pollution in counties and locations deemed particularly important, including preventing metropolitan areas, using mass tests, investigating cases immediately, and increasing vaccination rates as a priority” .
Although the government in the statement classified the new strain as VOC, an acronym used to describe forms of the virus with mutations that are of paramount importance, there is still no consensus on its more transmissible or even dangerous potential from the perspective of the government public health. .
At the beginning of May, the WHO (World Health Organization) classified one of the three subtypes of the Delta variant as particularly worrying and confirmed that it is more contagious than the other mutants of the virus. In addition to the possibility of increased transmission, the Indian variant also has mutations that enable the virus to escape the protection provided by antibodies – the so-called immunological escape.
The most worrying mutations found in Delta are D614G (identified as the first mutation the ancestral coronavirus underwent and which was present in almost all subsequent strains), L452R (associated with up to 20% higher transmission and ability , the action of antibody) and P681R (also present in the alpha variant, the first variant identified in the UK in 2020).
Studies recently published in pre-print and without peer review showed that the P681R mutation enables a mechanism called cell-cell fusion of the virus. Basically, the virus binds to cells in the human body through the receptor binding region, also known as the spike-S protein, and once it’s in the cytoplasm, it takes over the cellular machinery to replicate its material. During the process of replication and division, more virus particles are eliminated to infect new cells and so on.
In the case of Delta Plus, this mechanism occurs in lung cells, which can further indicate that the disease is getting worse.
Delta Plus also has an additional mutation, K417N, which is present in the variant known as Beta (B.1.351 or first identified in South Africa). This mutation is one of the possible mechanisms by which the South African variant succeeds in escaping the antibodies formed after a natural infection with the virus. Taken together, these factors indicate that Delta Plus is more likely to be transmissible and bypassing the cellular protective response of the immune system as well as antibodies, but this potential risk has yet to be confirmed.
So far, the delta transmission remains dominant compared to other strains in Europe, which according to a study published on Wednesday (23) should reach up to 90% of the samples after the summer. In the UK, a recent UK government report indicated the presence of the variant in 99% of the samples sequenced.
In the United States, although the alpha variant is still dominant – about 7 out of 10 cases are of this mutant – Delta already represents 20% of the samples sequenced. According to the latest WHO report, it has already been found in 85 countries.
On the other hand, in addition to the 40 cases discovered, the transmission of Delta Plus does not seem to be very accelerated in India, which is now experiencing a moment of stabilization on a high plateau after the worst months of the pandemic in April and May of this year.
Two independent studies in Scotland showed that Oxford / AstraZeneca and Pfizer / BioNTech vaccines are effective against the Delta variant, although the overall effectiveness was slightly less than that against the Alpha variant – 60% versus 73% for the AstraZeneca and 79 vaccines % versus 92% for the Pfizer immunizer, odds still rated as good by experts.
In the past 24 hours, India recorded 50,848 new Covid cases and 1,358 new deaths – the country set the world record of 6,148 deaths in a single day on the 10th after the data was reviewed in one of the states and registered 5,444 in the United States Deaths were hit states on February 12th.