A new and slightly changed version of the Delta coronavirus variant has already spread to 11 countries so far, including the US and UK, raising fears that it could drive the next wave of infections across the world
As ever more SARS-CoV-2 variants emerge, governments and public health experts continue to consider the best strategies to contain their spread. There are currently 11 variants of the SARS-CoV-2 virus that the World Health Organization Trusted Source is monitoring.
One of these variants, the Delta plus variant — also known as B.1.617.2.1 or AY.1 — was first detected in India in February. And as of 24 August, the state of Maharashtra has already recorded 103 Delta Plus cases, with the state logging in 27 cases on Monday alone.
So how is this variant different, and can it escape vaccine protection?
What’s the difference between Delta and Delta Plus?
Delta Plus differs from Delta because of an extra mutation — K417N — located in the spike protein, which covers the surface of the SARS-CoV-2 virus.
The K417N mutation isn’t entirely new — it has “arisen independently in several viral lineages”, said Francois Balloux, director of the University College London Genetics Institute.
The Delta Plus variant was designated as a Variant of Concern on 22 June by the Indian government, citing its perceived increased transmissibility, ability to bind more strongly to receptors on lung cells, and potential to evade an antibody response.
However, it has not yet been designated ‘Variant of Concern’ by the World Health Organization neither by the United States Centers for Disease Control and Prevention.
Is the Delta Plus variant more threatening?
The Delta variant of coronavirus has been held responsible for the second wave of the pandemic in India. Several other countries too consider Delta as the factor behind a sudden surge of cases. Experts in India have said Delta Plus, already detected in Maharashtra, can be the reason behind the third wave.
Studies in India show that the Delta plus variant spreads more easily, binds more easily to lung cells and is potentially resistant to monoclonal antibody therapy, a potent intravenous infusion of antibodies to neutralise the virus.
Colin Angus, a public health policy analyst in the United Kingdom also noted that the Delta plus cases have primarily been in younger people.
But leading virologists say there isn’t enough data to prove that the variant was more infectious or led to a more severe disease compared to other variants.
Where is the spread of Delta Plus?
So far, Delta Plus has been reported in 11 countries, including countries such as India, US, UK, South Korea, China, Japan and Russia, but the number of cases per country only reflects samples that have been sequenced, and more data is needed to determine the actual rate of spread.
As of 25 June, the United States had the highest number of cases — 83. Highlighting the issue, Dr Anthony Fauci, the nation’s top coronavirus adviser, in an interview with NBC said, “Every country that it has gone into up to now, you’ve seen an escalation in cases where it’s pushed aside the variant that was dominant before it.”
In India, according to the official records, 70 cases of the Delta Plus variant were recorded as of 23 June.
At least another 39 cases have been discovered in the UK till July.
South Korea on 4 August reported that it had two cases of the Delta plus variant, one in a man in his forties with “no recent travel records” and the second from a person who recently returned from the US. Surprisingly, the second confirmed case had reportedly received both doses of the AstraZeneca vaccine.
Are vaccines effective against this variant?
According to the Indian health ministry, Delta plus could have a similar ability to evade immunity and an ability to reduce the effect of monoclonal antibody therapies used to treat COVID.
The unique mutations in the Delta variant mean the virus can escape the immune system to some extent. Indeed, Delta has shown to reduce the efficacy of vaccines somewhat. This means a single dose of vaccine may offer reduced protection.
However, a second dose has been shown to produce enough antibodies against symptomatic infection and severe disease. It’s important to remember most COVID vaccines don’t provide absolute sterilising immunity, but work to reduce the severity of the disease.
UK researchers found the Pfizer vaccine had an efficacy of 33 percent against Delta after a single shot, and 88 percent after both doses. In the case of the AstraZeneca vaccine, the efficacy was just 33 percent after the first dose but went up to 60 percent after the second dose.
The Delta plus variant might have a similar degree of reduction in efficacy against the vaccines currently in use. Though we’re yet see good data on whether this is the case.
Studies are underway in India to assess the effectiveness of vaccines against Delta plus.
What do we do now?
With all this information, the question arising is should we change our behaviours? Despite the mutations, no extra special measures need to be taken. We must continue to get maximum numbers of people vaccinated, increase genomic surveillance to track the evolution of the virus and follow COVID-appropriate behaviour.
With inputs from agencies