Dr Yong Poovorawan said Thais aged over 48 may have some immunity against monkeypox but anyone born after 1974 was unlikely to have protection.
Yong explained that this was because Thailand's mass vaccination with smallpox vaccine – which is known to be effective against monkeypox – ended around that year.
But with the country now facing a surge of overseas arrivals, including from countries where monkeypox has been detected, the government last week asked the World Health Organisation for a fresh supply of smallpox vaccine. As of Friday, there had been no reports of monkeypox cases in Thailand.
Yong said Thailand's vaccination campaign against smallpox was reduced in 1974 before being scrapped completely in 1980, when the disease was eradicated from the world.
He recounted his own experience as a new paediatrics graduate in 1974 and 1975, explaining that Chulalongkorn University had already stopped administering smallpox vaccine by that time.
However, he added that he had administered smallpox vaccine to Thai-Chinese children at a clinic in 1978, because the procedure was still popular with the Thai-Chinese community.
