Each variant has been named after a Greek letter to make it easier for the public. The cases of the Alpha variant have been reported in 172 countries, Beta in 120 countries, Gamma in 72 countries, and Delta in 100 countries. Given the increase in transmissibility, the WHO warned that the Delta variant is expected to rapidly outcompete other variants and become the dominant variant over the coming months.

How contagious is Delta variant?
 

The WHO has categorised Delta as the 'Variant of Concern' (VOC) because of its significantly increased transmissibility. As viruses spread by replicating themselves, it sometimes manages to change its genetics to not kill itself.

 

According to WHO, the Delta cases are rising while Alpha cases are declining. It has increased transmissibility compared to other variants.

 

As some countries eased restrictions, there was an increase in transmission around the world. The variant was responsible for India's surge in Covid-19 cases in April due to its contagious properties. It also has an increased risk of hospitalisation. By mid-June, the Delta variant accounted for 99 per cent of Covid-19 cases in the UK, according to Public Health England

 

The common symptoms of Delta variants are as same as others which include fever, cough, shortness of breath, headache, fatigue, nausea among others.

According to reports, there's no evidence yet that determines if the Delta variant can evade vaccines completely. The WHO states the vaccines are effective against all the variants but is in need of more data.

 

A recent Lancet study said adults fully vaccinated with the Pfizer-BioNTech vaccine are likely to have over five times lower levels of neutralising antibodies against the Delta variant. But as none of the coronavirus vaccines is 100 per cent effective, there can be infections even in fully vaccinated people.

 

The US National Institute of Health said India's Covaxin effectively neutralises both Alpha and Delta variants of coronavirus.

A mutation of the Delta variant, the Delta Plus variant is a fast emerging VOC and has reportedly been found in 11 countries already. The mutation is acquired from both the Delta and the Beta strain, which was discovered in South Africa.

 

The Indian government categorised Delta Plus as a VOC, after finding cases in Maharashtra, Kerala, and Madhya Pradesh. This variant reportedly spreads 60 per cent faster than Delta.