Three Reasons Why the India-Origin Delta Variant Is More Severe Than Other Variants

Protesters are demonstrating on the 14th (local time) in front of the Prime Minister's residence at 10 Downing Street, London, England, protesting the delay in the schedule for lifting the COVID-19 lockdown.
[Image source=Yonhap News]

[Asia Economy Reporter Cho Hyun-ui] Even leading countries in vaccination are postponing the return to normal life due to the Delta variant virus, which has spread to over 80 countries worldwide. Some predict that the Delta variant will soon overtake the UK-origin Alpha variant as the dominant strain.

Why is the Delta variant, first identified in India last October, more deadly than other variants such as Alpha, Beta (originating from South Africa), and Gamma (originating from Brazil)? It is difficult to detect easily because its symptoms differ from the existing COVID-19 symptoms, it is the most contagious, and additional mutations seem to be ongoing.

◆Easy to mistake for a cold=The symptoms of the Delta variant differ from the previously known COVID-19 symptoms. Instead of well-known symptoms like fever, loss of smell or taste, and cough, the Delta variant is accompanied by cold-like symptoms such as headache, runny nose, and sore throat, according to the BBC. There are also analyses suggesting it causes abdominal pain, vomiting, loss of appetite, hearing loss, and joint pain.

Recently, 95% of new confirmed cases in the UK are infected with the Delta variant. Professor Tim Spector of King's College London told the BBC, "The main symptoms of recent confirmed cases in the UK are different from before," and advised, "If you feel cold-like symptoms, you should get tested for COVID-19."

There is also analysis that symptoms may be more severe when infected with the Delta variant compared to other variants. The Guardian reported, "In Guangzhou, China, 12% of Delta variant infected patients worsened to severe symptoms within 3 to 4 days after symptom onset," adding, "This is four times higher than previous variants."

Source: World Health Organization (WHO) website

◆Fastest transmission among variants=Another risk factor is that the Delta variant has the fastest transmission speed among all discovered variants so far. The Delta variant is over 64% more transmissible than the Alpha variant. Ashish Jha, Dean of the Brown University School of Public Health, evaluated it as "the most contagious variant we have seen so far."

Because of this, in the United States, the number of Delta variant infections doubled every two weeks, accounting for 10% of all confirmed cases as of the 13th. The UK, which postponed the full lifting of lockdown due to the Delta variant, recorded 10,000 new confirmed cases yesterday, the first time in four months since mid-February.

◆Possibility of additional mutations=Additional mutation patterns are also emerging. The World Health Organization (WHO) is tracking another sub-variant of Delta called 'Delta Plus.' Maria Van Kerkhove, WHO's COVID-19 technical lead, explained, "It is considered an additional mutation," and added, "Among some Delta variants, mutations are occurring by removing something rather than adding something to the existing variant virus."

In South Korea, the Delta variant is the second most common after the Alpha variant. Since December last year until midnight on the 12th, 1,964 confirmed cases of variant viruses have been identified domestically. Alpha accounts for 1,663 cases, the highest, followed by Delta with 155 cases. Beta and Gamma account for 140 and 6 cases, respectively.