The number of confirmed cases of the Omicron variant of the coronavirus has jumped sharply, with health authorities fretting about a possible spread from a cluster in Kalasin where 100 people are at deemed at-risk due to their close contact with patients.
Department of Medical Services chief Supakit Sirilak said on Friday that total cases of the Omicron variant had risen to 205 as of Thursday night.
The figure rose sharply from 104 cases on Tuesday.
Dr Supakit said 25 Thais were among 205 people who were in close contact with patients who arrived from abroad.
There were 2,671 new cases and 27 more fatalities registered in the 24 hours to midnight on Thursday, the Public Health Ministry report on Friday.
The Centre for Covid-19 Situation Administration said 84% of the confirmed cases in the country were the Delta variant and 16% Omicron. However, 53% of patients arriving from other countries were confirmed infected the Omicron variant, the other 47% with Delta.
With the number of Omicron cases clearly on the rise, health authorities were concerned about an Omicron cluster in Kalasin, where 100 people were at risk as a result of close contact with a couple who returned from visiting relatives in Belgium.
The husband and wife, both aged 47, arrived at Khon Kaen airport via Suvarnabhumi from Belgium on Dec 11 and their RT-PCR test at Kalasin Hospital five days later was positive. 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 Omicron variant.
Dr Supakit said 19 other people who were in close contact with the couple also tested positive, bringing the total in the Kalasin cluster to 22.
What worried the Public Health Ministry about the Kalasin cluster was that the couple travelled to other places in their home province and in neighbouring Khon Kaen after arriving back.
The places they visited included bars, a shopping mall and state 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, THAI Smile WE046 on Dec 11, to closely monitor their health and urgently contact officials if they develop symptoms common to the coronavirus.