Dr. Yong clarifies the doubts about COVID-19 currently spreading in Singapore and whether it affects Thailand, revealing that most of the population already has prior immunity.
On 25 May 2026, Professor Dr. Yong Poovorawan, head of the Clinical Virology Expertise Center at the Faculty of Medicine, Chulalongkorn University, posted a message regarding " "Does the COVID-19 outbreak in Singapore affect Thailand?" He stated, "There have been reports that COVID-19 is spreading widely in Singapore, especially the NB.1.8.1 variant.
This variant caused a significant outbreak in Thailand last year, from after Songkran until throughout the rainy season, then began to decline toward the end of the year and up to now. It is therefore quite surprising why Singapore is seeing an outbreak of NB.1.8.1, as worldwide variants have evolved considerably to letter R, particularly RV.1.
However, the variant itself is not very significant because it does not increase severity, and most of the population already has prior immunity. Thus, the Singapore variant is unlikely to impact Thailand since we have already experienced it. The outbreak in Singapore is seasonal; historically, Singapore experiences high COVID-19 cases around this time each year.
In Thailand, over the past two years, COVID-19 outbreaks have clearly occurred after Songkran, starting from late April, peaking in May and June, then gradually declining by August and continuing sporadically.
Regarding the variants circulating in Thailand over the past two years, it is clear that the NB.1.8.1 variant that spread in Singapore was present in Thailand early last year but has since disappeared. Therefore, the variant spreading this year is unlikely to be NB.1.8.1.
This year is unusual, possibly due to very hot weather. Despite normal Songkran celebrations with many people playing in water, no major COVID-19 outbreak followed immediately. Cases began to rise only recently, especially with schools reopening, where students accelerate the spread of respiratory diseases rapidly. It is believed the outbreak coincides with other respiratory viruses like influenza and rhinovirus (common cold).
Currently, the variant is being monitored and will be reported later. It is believed to be a newer variant rather than NB.1.8.1. Regarding the cicada variant, the World Health Organization identified it as a variant of interest two months ago, but it has since disappeared without causing impact. Overall, the disease severity is similar to other respiratory infections.
Reported case numbers to the Ministry are much lower than reality because many cases are detected at home or go untested, so they are not reported. Most reported cases come from hospitals, making official figures significantly underestimated. Our center monitors eight respiratory viruses and will continue to provide updates.
Thailand should not be alarmed, as the disease severity has not increased; death rates are similar to influenza. Nearly all Thai people have immunity to this disease, reducing its impact. Most children experience mild infection and develop immunity, except very young infants who usually receive maternal antibodies for the first six months.
Everyone has a role in reducing disease spread, especially among students. Recommended measures are similar to those during major COVID-19 outbreaks: proper handwashing with five steps, using alcohol-based sanitizer when handwashing is unavailable, and wearing masks in crowded public places such as on packed trains. Normally, students do not need masks, but sick individuals or those feeling unwell should wear masks to reduce transmission. Healthy people do not have to wear masks but may choose to do so. Eating hygienically using shared utensils should be strictly practiced.
As the disease becomes less severe and seasonal like other respiratory illnesses, the need for vaccination greatly decreases. Compared to influenza vaccines, COVID-19 vaccines are ten times more expensive and must be paid for privately. Influenza vaccines have been used for over 50 years, while COVID-19 vaccines were introduced during the pandemic amid rapidly evolving variants. Vaccine manufacturers have not kept pace with variant changes, and COVID-19 vaccines have more side effects, such as higher rates of post-vaccination fever. Therefore, the necessity of COVID-19 vaccination is low compared to the annual influenza vaccine.
Thanks to Facebook page Yong Poovorawan