The Public Health Ministry will recommend the suspension of the "Test and Go" convenient entry programme for fully vaccinated air travellers because of the escalating Omicron variant situation worldwide.
Deputy Prime Minister and Public Health Minister Anutin Charnvirakul said on Monday that he would put the proposal to the Centre for Covid-19 Situation Administration.
Test and Go currently applies to fully vaccinated visitors from specific countries.
He said all arrivals should be through the Sandbox and State Quarantine schemes.
Dr Supakit Sirilak, director-general of the ministry's Department of Medical Sciences, said one Omicron case who entered the country via Test and Go had tested negative for Covid-19 both before and upon arrival, but a few days later the visitor fell ill and tested positive for the new variant.
Therefore, Test and Go should be reviewed because the case had been within the window period of the infection, 6-7 days, he said.
"If Test and Go is not reviewed, then infected but undetected arrivals can right away travel farther inside the country and cause clusters of infections," Dr Supakit said.
Dr Supakit said that as of Sunday, Omicron cases were found in 89 countries and 39 states in the United States. Actually, it could be in more countries that were not capable of confirming the variant's presence.
"The infection rate will be expanding," he said.
He said Thailand had detected more than 80 Omicron cases to date. There were 11 cases from April to Dec 10, 52 cases from Dec 11 to 19, and more cases were reported on Monday morning.
"Most Omicron cases detected were arrivals at Suvarnabhumi airport and they formed a quarter of the Covid-19 cases found there. The case numbers increased quite quickly over the past week, which corresponded with the global situation," he said.
However, all Omicron cases were arrivals and there had not been a local infection of the new variant, he said.
According to Dr Supakit, there have been three sub-variants of Omicron but their infections remained limited.
The infections spread quickly, but there was insufficient information to determine if the new variant caused severe illness. Vaccines were less effective at containing the new variant, but booster shots could help protect recipients, he said.