What is Delta Variant and why is it of concern?

Aditi Malewar
Wednesday, 23 June 2021

The Centre has alerted and advised Maharashtra, Kerala and Madhya Pradesh against Delta variant of SARS-CoV-2.

With new cases of Delta variant infection in the country, the Centre has recently alerted and advised Maharashtra, Kerala and Madhya Pradesh the mutate variant of SARS-CoV-2. The new variant is currently ‘Variant of Concern (VOC)’.

According to Tuesday’s press release of the Ministry of Health and Family Welfare, the ministry has advised the respective states that the ‘Public Health Response measures, while broadly remaining the same as have been implemented by them earlier, have to become more focused and effective.’ The advice followed the Indian SARS-CoV-2 Consortium on Genomics’ (INSACOG) feedback on the Delta Plus variant. 

The Centre has further advised the states' chief secretaries ‘to take up immediate containment measures in the districts and clusters (as identified by INSACOG), including preventing crowds and intermingling of people, carrying out widespread testing and prompt tracing as well as vaccine coverage on a priority basis.’

But what is Delta Variant?

There have been multiple COVID-19 variants globally – B.1.1.7 (UK Variant; Alpha), P.1 (Brazil Variant; Gamma), and B.1.617 (Indian Variant; Delta), among others. Recently a new variant - B.1.617.2 - has been responsible for new cases in the UK and now in India. 

Variants are formed when there is a mutation or alterations in the main virus’s genetic material. SARS-CoV-2, which is an RNA virus, is made of multiple pairs of amino acids and any alteration in these can cause a mutation. This would change the behaviour of the virus and the Delta variant contains several mutations in the spike proteins.

Earlier in June, the UK Health Minister Matt Hancock revealed that the Delta variant is ‘40 per cent to 50 per cent more transmissible’ than the Alpha strain, which was detected in the UK. In India, the Indian SARS-CoV-2 Consortium on Genomics (INSACOG) too suggested that the new variant has increased transmissibility. INSACOG further suggested that the variant binds stronger to the receptors of lung cells, and may have a potential reduction in monoclonal antibody response. The World Health Organisation (WHO) has categorised it as a variant of concern (VOC). 

Are vaccines are effective against B.1.617.2?

In India, there is very little evidence of how B.1.617.2 would react to the vaccine. However, Public Health England’s (PHE) analyses from England and Scotland suggests that, compared to the Alpha strain, there is a reduction in vaccine effectiveness for the Delta variant. PHE states that ‘all analyses continue to support increased transmissibility and reduced vaccine effectiveness against symptomatic infection.’ The organization’s Risk Assessment reports also suggest that the “…vaccine effectiveness against Delta is higher after 2 doses but that there is a reduction for Delta compared to Alpha.”

According to reports, currently, there are about 40 cases of Delta Variant in India. So it’s too to say what kind of effect the vaccines would have on the variant.



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