Delta goes global: Here's all you need to know about the Covid-19 variant

The spread of the Delta variant, also known as the B.1.617.2 variant of the Covid-19 virus lineage, that has been partly blamed for the havoc wreaked during India’s second wave, is being monitored closely by countries like the United Kingdom, Australia and United States as cases of the variant tick up.

In May, the World Health Organization (WHO) had classified this lineage as a variant of concern (VOC), saying it showed signs of higher transmissibility and was more likely to evade the body’s immune response.

What is the Delta variant?

The Delta variant is one of the variants within the B.1.617 lineage of the Covid virus that was identified earlier this year in India and then spread across the country. The lineage is fast-spreading and soon came to dominate the new cases that appeared in the country over the pandemic’s second wave.

Read | Third wave will strike India in 6-8 weeks if Covid-appropriate behaviour is not followed: AIIMS chief

Why is the Delta variant a VOC?

The Delta variant has some key mutations in its spike protein that make it more easily transmissible and deadly. A Public Health England study in May showed that the variant had much higher attack rates — the number of new cases that emerge in a population over time — than the Alpha variant first identified in the UK.

How much faster does the Delta variant spread?

Studies have shown that the Delta variant is almost 60 per cent more transmissible than the Alpha variant, which itself was 50 per cent more transmissible than the original Covid-19 virus that broke out in late 2019.

Why is it much more deadly?

The mutations that define the Delta variant have changed the spike protein in a way that existing antibodies may not bind as tightly or as often as with earlier variants, reducing the effectiveness of the body’s immune response.

Also Read | Telangana to completely lift Covid-19 lockdown from June 20

Do vaccines work against the variant?

Most studies so far have shown that vaccines still offer protection against the Delta variant, even though they are less effective. A Public Health England study showed that a single shot of the Pfizer-BioNTech vaccine or the Oxford-AstraZeneca vaccine gave the recipient 33 per cent protection against the symptomatic disease, which increases to 88 per cent and 66 per cent, respectively, after two doses.

How far has the Delta variant spread?

The Delta variant has already spread to more than 70 countries and is now the most dominant variant in India, the UK and Singapore. Last week, the Delta variant was behind more than 90 percent of new COVID-19 cases in the UK, leading to a 65 per cent jump in new infections since May. Several health experts and scientists have said the variant was on its way to become the dominant form of the virus all over the world.