The medical fraternity and scientists in India are keeping a close watch on the delta and delta plus variants, which they now believe may contribute towards the emergence of the third wave of COVID. This article throws light on the characteristics of both and delivers quick pointers on what doctors should know about them.

For our comprehensive coverage and latest updates on COVID-19 click here.

---

The new coronavirus variant

The Maharashtra health authority has cautioned that if COVID-appropriate behaviour is not followed, the delta plus form of the new coronavirus might trigger a third wave of illnesses within a month or two. While the second wave had a considerably greater patient count than the first due to the virus' delta variation, the third wave may even have a higher patient count.

The novel ‘delta plus’ variation was created as a result of a mutation in the coronavirus delta or B.1.617.2 variant. The common infectious delta variant of the new coronavirus has evolved into the delta plus or AY.1 variant. However, the Union health ministry has said that this variety of COVID-19 illness is not currently a 'variant of concern.'

On June 15, NITI Aayog Member (Health) VK Paul stated during a news conference that a new mutation known as the delta plus variant has been identified in Europe since March 2021.

The NITI Aayog Member (Health) VK Paul stated:

"This is an unclassified variation of interest. A variation of concern (VOC) is one in which we have concluded that an increase in transmissibility and severity would have negative repercussions for mankind. This is unknown now regarding the Delta plus variant."

Paul continued by stating that the effect and change of delta plus must be monitored scientifically using the INSACOG system. “This must be identified and its presence in the country established,” he stated.

The government established the Indian SARS-CoV-2 Genetics Consortium (INSACOG) on December 25, 2020, to investigate and monitor the genome sequencing and viral variation of COVID-19 circulating strains in India.

---

Salient features of the COVID-19 Delta plus variant

1. The novel delta plus variation of COVID-19 was generated as a result of a mutation in the delta or B.1.617.2 variant, which was initially detected in India and was one of the drivers of the lethal second wave of COVID-19.
2. Delta plus is resistant to the recently approved monoclonal antibody cocktail therapy for COVID-19 in India.
3. According to Vinod Scaria, physician and scientist at Delhi's CSIR-Institute of Genomics and Integrative Biology (IGIB), the mutation occurs in the SARS-COV-2 spike protein, which aids the virus in entering and infecting human cells.
4. At the moment, the variation frequency for K417N is rather low in India.
5. The first sequencing of this genome was discovered in late March 2021 in Europe. As travel histories for the variation are not easily available, a crucial factor to examine in relation to K417N is data showing resistance to the monoclonal antibodies Casirivimab and Imdevimab.
6. It is further suggested that the mutation may be related with the virus's capacity to evade the immune response.
7. According to Public Health England, the worldwide scientific effort GISAID has found 63 Delta (B.1.617.2) genomes containing the novel K417N mutation.

---

What should physicians learn about delta?

With stories of a more transmissible delta variation, and now 'Delta plus' sweeping the news, here are the important facts regarding the current version in the limelight.

---

How is the delta variant defined?

The delta version, or B.1.617.2, initially appeared in India in October 2020. However, it was not until India encountered a significant COVID-19 outbreak this spring that it became a cause for concern, according to the CDC and the World Health Organization (WHO). B.1.617.2 is a variation of B.1.617, the initial "India" variety (named Kappa and only a variant of interest). Additionally, there is B.1.617.3 (an interesting variation) and, more recently, B.1.617.2.1, which has been termed "Delta plus" in the media and is not yet on the CDC or WHO lists.

---

Is Delta more spreadable?

Delta appears to be more transmissible. The CDC uses a Public Health England research in which 3,765 cases (household clusters) were matched to 7,530 controls (single case in a home) to assess the probability of household transmission of the delta variant (B.1.1.7), which first arose in the United Kingdom. Delta was shown to be 64 per cent more transmissible than alpha in household transmission (95 per cent confidence interval [CI] 1.26-2.13, P0.001). It was calculated that alpha was 50% more highly infectious than the wild-type virus.

---

Is Delta greater virulent than other strains?

It is unknown if Delta produces more severe illnesses or more fatalities. Evolutionary biologists and virologists agreed that there are several reasons why virulence epidemiology might be complex — for example, if a surge overwhelms a hospital. Nonetheless, preliminary epidemiological evidence from England and Scotland indicates that Delta may be more pathogenic. A Public Health England review of about 43,000 COVID-19 patients found an increased risk of hospitalisation with delta compared to alpha (HR 2.26, 95 per cent confidence interval (CI) 1.32-3.89, P=0.003).

Additionally, research published in The Lancet by Public Health Scotland discovered that individuals with the delta variation had an 85 per cent increased risk of hospital admission compared to those with the Alpha variant (HR 1.85, 95 per cent CI 1.39-2.47).

---

Vaccines: Are they effective against Delta?

According to data from England and Scotland, vaccinations continue to protect against delta, albeit the variation reduces their effectiveness slightly. Public Health England found a 10% absolute drop in total vaccination efficacy (two doses) against symptomatic illness with delta compared to alpha in its most recent analysis (79 per cent vs 89 per cent). In terms of hospitalisations, complete immunisation provided comparable protection against delta (96 per cent) and alpha (93 per cent).

Research released in late May on the preprint platform medRxiv by Public Health England revealed that Pfizer's injection looked to be a better protective agent against symptomatic delta illness than AstraZeneca's jab (87.9 per cent vs 59.8 per cent).

The Lancet research from Public Health Scotland found comparable results, demonstrating significant – if somewhat decreased – efficacy against symptomatic delta infection. Additionally, this study discovered that Pfizer's vaccination was more effective (79 per cent) than AstraZeneca's vaccine (60 per cent).

Additionally, Moderna published data from a minor laboratory trial indicating that their mRNA vaccine caused just a "modest decrease" in neutralising antibodies against Delta.

While new infections can occur following vaccination particularly with Delta, modern vaccinations continue to give good protection against illness and death when compared to no immunisation.

---

How effective are monoclonal antibodies against it?

According to the CDC, several presently permitted monoclonal antibody therapies may result in a "potential decrease in neutralisation." The United States halted the distribution of Eli Lilly's monoclonal antibody combination (bamlanivimab/etesevimab) last week owing to insufficient activity against the Gamma (P.1) and Beta (B.1.351) versions. Regeneron has claimed that their monoclonal antibody combination casirivimab/imdevimab has no effect on Delta neutralisation. The same is true with sotrovimab, which is marketed by GlaxoSmithKline and Vir Biotechnology.

---

Are children at a higher risk of delta?

Parents, in particular, have inquired if the delta version offers an increased risk to children. While there is no evidence that this is true physiologically, experts are concerned about children's susceptibility as a result of their lack of vaccination. Recently, infections in children accounted for half of Israel's new COVID infections, a trend that coincided with the reopening of the country's schools in May. Nonetheless, there is no evidence that delta is more severe in children.

---

Why are people so concerned?

Delta might be particularly dangerous for people who have not yet received their vaccinations.

---

Click here to see references

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author is a practising super specialist from New Delhi.