About 16% of Covid-19 infections detected in Thailand so far have been proven to be cases of the Omicron coronavirus variant, according to the latest random sample collected by the Public Health Ministry.
Apisamai Srirangson, assistant spokeswoman for the Centre for Covid-19 Situation Administration (CCSA), said that there were 205 confirmed cases of the Omicron variant in Thailand as of Friday. The figure rose from 154 cases on Wednesday.
She also said a random sample of 874 Covid-19 cases was conducted between Dec 20-23. Of them, 16.2% were the Omicron variant while the rest were the Delta strain.
Of the 874 cases, some 221 were arrivals from other countries under the Test & Go scheme and more than half of the arrivals or 52.9% were confirmed to be infected with the Omicron variant, she said.
"The figures are based on reports of Test & Go arrivals sent in from each province," Dr Apisamai said.
This shows a rapidly increasing rate of Omicron cases detected in the country, but generally, Delta remains the dominant variant in Thailand, she said.
A breakdown of the figures into provincial cases shows 56.5% of cases in Bangkok were still the Delta variant while 43.5% were the Omicron strain. In other provinces, most cases were still the Delta variant, Dr Apisamai said.
The Omicron variant is proving far more transmissible than Delta.
With the number of Omicron cases clearly on the rise, health authorities were concerned about a cluster of 22 confirmed cases of Omicron linked with a couple also infected with the new strain in Kalasin. Several people were at risk as a result of close contact with the couple who had returned from Belgium.
Dr Opas Karnkawinpong, director-general of the Department of Disease Control, said the 22 cases are the first cluster of local Omicron transmissions in the country spreading in Kalasin and Udon Thani.
He said the case involving the Kalasin couple underscores the need to temporarily suspend the Test & Go scheme and revise travel measures for arrivals from other countries.
The husband and wife, both aged 47, arrived at Suvarnabhumi airport from Belgium on Dec 10 under the Test & Go scheme.
Their RT-PCR test upon arrival came back negative on Dec 11. They then took a THAI Smile WE046 flight to Khon Kaen where their relatives drove them in a pickup truck to Kalasin.
Their second RT-PCR test at Kalasin Hospital on Dec 17 was positive and later confirmed to be the Omicron variant, according to health authorities. They were being treated at a hospital in Khon Kaen.
Their son-in-law, 22, who lives in Udon Thani, visited them in Kalasin and he was later found infected with the variant.
According to the Public Health Ministry, 19 other people who were in close contact with the couple also tested positive with Omicron, bringing the cluster number linked with the Kalasin couple to 22.
What is worrying about the cluster was that the couple travelled to other places in their home province and in neighbouring Khon Kaen after arriving back, health authorities said.
The places they visited included a shopping mall and government offices in Kalasin. The husband also travelled in a public van to a passport office in Khon Kaen.
The public health office in Khon Kaen on Monday advised people in places they visited and people on the same flight to Khon Kaen on Dec 11, to closely monitor their health and urgently contact officials if they develop symptoms common to the coronavirus.