NEW DELHI: The Delta variant of Covid-19 — which first appeared in India — has started spreading rapidly in the United Kingdom and was also recently detected in Australia. Both countries have registered a sharp increase in new infections over the past week.
The B.1.617 variant of the virus, which has in part been blamed for India’s explosive outbreak, has been dubbed a triple mutant variant since it is split into three lineages: B.1.617.1, B.1.617.2 and B.1.617.3.
Of these, B.1.617.2 has been identified as a variant of concern (VoC) by the World Health Organization and was last week renamed as the Delta variant. It is said to be highly transmissible.
Meanwhile, B.1.617.1, or Kappa variant, has been identified as a Variant of Interest (VoI).
The B.1.617.3 strain has not been classified as either VoC or VoI since there have been very few reports of people being infected by the strain.
‘Delta variant could be responsible for India’s second wave’
- The Delta variant, which is “more infectious” than the Alpha variant, is the “primary cause” behind the second wave of the Covid-19 pandemic, as per a study by the Indian SARS-CoV-2 Consortium on Genomics (INSACOG).
- The Alpha variant, or B.1.1.7 is the strain first identified in the UK.
- B.1.617 variant & its lineage B.1.617.2 (Delta) were primarily responsible for the surge in cases with high transmissibility of 50 per cent more than the Alpha variant (B.1.1.7), said the study.
- The Delta variant is present in all states across India but has infected people mostly in Delhi, Andhra Pradesh, Gujarat, Maharashtra, Odisha, and Telangana, which were the worst hit in the second surge.
- The study said the variant may have caused around 60% of the cases in Delhi in April this year.
- However, it said the role of the Delta variant in causing more deaths or leading to severe cases is not yet established.
- Genomic variants of various viruses are a natural phenomenon and are found in almost all countries.
‘Delta now dominant VoC in United Kingdom’
- The Delta variant has now become the dominant Variant of Concern (Voc) in the United Kingdom.
- Health officials in Britain have said that Delta may also come with an increased risk of hospitalisation compared to the Alpha VoC which was first detected in Kent, England.
- According to Public Health England (PHE), which monitors all
Covidvariants in the country, Delta variant infections rose by 5,472 in a week to hit a total of 12,431 on June 3.
- The latest statistics have led experts to conclude that Delta is now closing in to overtake Alpha.
- The majority of the patients infected by the Delta variant had not been vaccinated, PHE said.
- The areas most affected by the Delta variant remain in the north west of England with Bolton, where cases increased by 795 to 2,149. In Blackburn, Darwen recorded 368 new cases, bringing its total to 724.
- However, the PHE said there are “encouraging signs’” that the transmission rate in Bolton has begun to fall.
Delta VoC found in Australia’s Melbourne
- The Australian city of Melbourne has detected two Variants of Concern (VoC) first found in India, namely Kappa and Delta.
- While Kappa is said to be responsible for the latest surge in cases, Victoria state authorities on Friday said that they have detected the Delta VoC for the first time in Melbourne.
- Victoria state chief health officer Brett Sutton said the new variant had not been linked to any sequenced Covid-19 infections across Australia from hotel quarantine or elsewhere.
- Sutton said that it was a concern that it is not linked to other cases but the authorities are chasing primary cases to look where it might have been acquired.
- The Delta variant was detected in two members in a family who travelled to the neighbouring state New South Wales (NSW) two weeks ago.
- While likely infectious, the two visited several tourist locations. However, NSW, Australia’s most populous state, has not reported any locally acquired cases in a month.
Renaming of Covid-19 variants: Alpha, Beta, Gamma, Delta & Kappa
Earlier this week, the World Health Organisation (WHO) renamed the various Covid-19 variants detected in different parts of the world, recognising them through Greek alphabets instead of their country of origin.
Vaccine effectiveness against Delta variant
- Vaccine effectiveness refers to how well a vaccine works in the real world, as opposed to the term efficacy, which relates to vaccines’ performance in trials.
- As per a research study published in The Lancet, people fully vaccinated with the Pfizer-BioNTech vaccine are likely to have more than five times lower levels of neutralising antibodies against the Delta variant compared to the original strain.
- The study also shows that levels of these antibodies that are able to recognise and fight the virus are lower with increasing age and that levels decline over time.
- As per the study, after just one dose of the Pfizer-BioNTech vaccine, people are less likely to develop antibody levels against the B.1.617.2 variant as high as those seen against the previously dominant B.1.1.7 (Alpha) variant.
- Some other studies have suggested that current Covid vaccines are somewhat less effective against the Delta variant than the Alpha variant.
- As per reports, while the vaccines do provide protection, a second dose is important for feasible results against the Delta variant.
(With inputs from agencies)