Dr Yong Poovorawan, head of the Centre of Excellence in Clinical Virology at Chulalongkorn University, said cases of the Delta variant first found in India would overtake Alpha cases in four months at the current infection rate. He also warned of the likely emergence of other variants.
While the Alpha, Beta and Delta variants do not affect the severity of the disease, they do blunt the efficacy of vaccines, Yong added.
For example, the efficacy of two doses of Pfizer vaccine drops from 90 per cent to 79 per cent when faced with Delta while AstraZeneca falls from 73 to 60 per cent.
There is limited data on the efficacy of Sinovac and Sinopharm vaccines against Delta, but early research at the Centre of Excellence suggests it might fall to as low as 30 per cent.
Administering a third dose of vaccine after 3-6 months has been proposed to help boost immunity.
Dr Yong said the infection rate must be reduced if Thailand is to meet the government’s deadline of reopening the country by October. Vaccination and people’s hygiene habits were key in achieving that goal, he added.
Published : June 22, 2021
By : The Nation