The Korea Disease Control and Prevention Agency (KDCA) said on Tuesday South Korea has discovered its first two cases of the new Delta Plus COVID-19 variant, as the country struggles with its fourth wave of infections.

The Delta Plus variant is a sub-lineage of the Delta variant first identified in India, and has acquired the spike protein mutation called K417N, which is also found in the Beta variant first identified in South Africa.

Delta Plus cases are few so far, it was detected in some countries including Britain, Portugal and India, have reported some cases.

“The first case (in South Korea) was identified in a man in 40s who has no recent travel records,” the KDCA told Reuters. The source of transmission is under investigation

a KDCA official told a briefing that test results in around 280 people who were in contact with the man found that only his son Park Young-joon was positive too.

Park said it was unobvious whether the son was also infected with Delta Plus.

The second case was found in a traveler who returned from the US. The person had been inoculated with both shots of AstraZeneca before the trip, Park said.

Several major vaccines work against the highly infectious Delta variant, health authorities have said, which has already become dominant in many countries, but have raised concern new strains may evade some vaccines.

Genetic analysis of 3,014 infections last week found 64 percent were the Delta variant, KDCA data showed, a clear sign the variant has become the dominant strain in South Korea as well.
Cases among the fully vaccinated remained low.

Some scientists have said the Delta Plus variant may be even more transmissible. Studies are ongoing in India and globally to test the effectiveness of vaccines against this mutation.

South Korea reported 1,202 new COVID-19 cases for Monday, raising the total to 202,203 infections, with 2,104 deaths.

The country on Tuesday said it has given 20 million people, or 39 percent of its population, at least one dose of a vaccine, while 14.1 percent have been fully vaccinated.

South Korea aims to immunize at least 36 million people by September.