Thailand urges calm over S’pore’s Covid-19 spike; no severe outbreak from dominant NB.1.8.1 strain

Thailand's Department of Disease Control is advising the public against panic over a recent surge in COVID-19 cases in Singapore. Officials state that the NB.1.8.1 variant, identified as the primary driver of concern in Singapore, is already circulating widely in Thailand and has become the country's dominant strain.

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NB.1.8.1 is not a new threat suddenly entering Thailand from abroad, as the variant has already been detected in the country and now accounts for 50.95 per cent of sequenced samples.

Director-General Montien Kanasawat reported that Thailand had logged 3,642 cumulative COVID-19 cases and one death between January 1 and May 23, 2026. While cases have increased over the past month, the numbers remain below the five-year median. Data indicates that NB.1.8.1 accounts for 50.95% of sequenced samples in Thailand, followed by JN.1 (24.97%) and XEC (9.14%). Most reported cases in 2026 were among individuals aged 30-35, with significant numbers also in the 60+ and 20-29 age groups.

The public concern arose following a sharp rise in Singapore, which reported 12,700 COVID-19 cases during the week of May 10-16, an increase from approximately 8,000 the previous week. Average daily hospitalizations in Singapore also rose, though intensive care unit cases remained low. NB.1.8.1 was identified as the main variant in Singapore, making up over half of detected cases.

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These changes may make the virus easier to transmit and better able to evade immunity. However, he stressed that there is still no evidence that NB.1.8.1 causes more severe illness.

Dr. Montien clarified that NB.1.8.1 is a descendant of the JN.1 variant and possesses additional mutations on its spike protein. These changes might enhance its transmissibility and ability to evade immunity, but he stressed that there is currently no evidence suggesting it causes more severe illness. Thailand has also observed an increase in COVID-19 cases and outbreaks from April to June 2025, with NB.1.8.1 identified as the leading variant during that period. Officials are treating COVID-19 as an endemic disease but advise continued basic precautions, especially during the monsoon season when respiratory illnesses typically spread more easily.

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Covid-19 in Thailand is now treated as an endemic or seasonal communicable disease.