BANGKOK—Thailand’s government is in talks with Merck & Co to buy 200,000 courses of its experimental antiviral pill for COVID-19 treatment, the latest Asian nation to scramble for supplies of the drug after lagging behind Western countries for vaccines. Somsak Akksilp, director-general of the Department of Medical Services, told Reuters that Thailand is currently working on a purchasing agreement for the antiviral drug, known as molnupiravir. South Korea, Taiwan, and Malaysia said they are also in talks to buy the potential treatment, while the Philippines, which is running a trial on the pill, said it hopes its domestic study would allow access to the treatment. They all declined to provide details on purchase negotiations. The molnupiravir pills, designed to introduce errors into the genetic code of the virus, would be the first oral antiviral medication for COVID-19. Many Asian countries want to lock in supplies early after they were hit …