Photo: Asad Photo Maldives / Pexels
Thailand's Dominant Covid Strain in 2025–2026: What Visitors Need to Know
Thailand's current dominant Covid-19 strain is NB.1.8.1, which has been circulating since mid-2025. Health authorities say the variant spreads more easily than some earlier strains but is not causing more severe illness. Case numbers have risen slightly with the season but remain below the five-year median, and there are no signs of widespread outbreaks. For visitors to Koh Lanta, the practical message is straightforward: stay aware, take basic precautions, and know what to do if you feel unwell.
About the NB.1.8.1 Variant
NB.1.8.1 accounts for around 51% of detected Covid strains recorded in Thailand between January 1, 2025 and April 23, 2026. The next most common strains are JN.1 at roughly 25% and XEC at just over 9%. The variant carries mutations linked to increased transmissibility and immune evasion, meaning it may spread more readily and partially sidestep prior immunity. However, according to Dr. Montien Kanasawat, Director-General of the Department of Disease Control (DDC), current data shows no increase in symptom severity or mortality risk compared to earlier strains.
Current Case Numbers
As of June 2, 2026, Thailand's Digital Disease Surveillance (DDS) system had recorded 4,156 cases and one death. The most affected age group is 30 to 39 year olds, followed by people aged 60 and above, then those aged 20 to 29. Thailand monitors Covid-19 through a network of 26 sentinel hospitals nationwide, alongside event-based monitoring and laboratory surveillance.
Symptoms to Watch For
Most people infected with NB.1.8.1 experience symptoms similar to a common cold or flu: fever, cough, sore throat, and a runny nose. If you develop any of these symptoms, the DDC advises taking an initial self-screening test. Avoid close contact with others while symptomatic, particularly with elderly people, those with underlying health conditions, and pregnant travelers, who face a higher risk of complications.
Seasonal Risks
Cases have risen over the past month in line with seasonal patterns. Dr. Direk Khampaen, DDC Deputy Director-General, notes that Covid-19 is a year-round respiratory infection in Thailand, with transmission more likely during the rainy season when people spend more time indoors in crowded spaces. This is worth keeping in mind if you are visiting during that period.
Basic Precautions
A few simple habits go a long way. Wash your hands regularly, wear a face mask in crowded indoor spaces or if you are feeling unwell, and avoid close contact with anyone who appears sick. If you need health information or guidance while in Thailand, you can call the DDC hotline on 1422.
Information sourced from The Thaiger.