Medical Sciences Department Director-General Dr. Supakit Sirilak predicted that, in the next 2-3 months, the Delta (Indian) variant of COVID-19 may replace the Alpha (UK) strain as the dominant COVID-19 strain in Thailand, because it is 40% more transmissible than the Alpha variant.

He said the Medical Sciences Department has been monitoring 5,055 cases of infected people since April and found that 89.6% of them were infected by the Alpha strain and only 9.8% by the Delta variant, including 404 cases in Bangkok, as well as three infected by the Beta (South African) strain in three districts of the southernmost province of Narathiwat.

10 patients under treatment in as many as 4 hospitals in Bangkok were found to be infected with the Delta variant, he added.

The Medical Sciences Department plans to conduct research on the efficacy of vaccines on different variants of the virus, using about 200 volunteers, by taking their blood samples for tests with virus variants to determine their immune response.

According to Dr. Supakit, after two doses of Sinovac, immune response towards the original variant from China is almost 100%, but the antibodies drop to 50-60% with the Alpha variant.

Research on immune response from one dose of AstraZeneca vaccine to the Alpha and Delta variants is still underway.

The head of Medical Sciences also said, however, that there is no need to spend money on checking immune response after vaccination, which should be the responsibility of his department.