The Delta variant of Covid-19 has spread to all 77 provinces, along with four sub-variants that have not shown themselves to be especially harmful mutations yet, a senior medical official said on Tuesday. Dr Supakit Sirilak, director-general of the Department of Medical Sciences, said the Delta variant had spared Suphanburi province until this week, but had now been detected there. He said widespread outbreaks of a variant naturally led to sub-variants. However, they were not Thai variants because they had been previously found in Britain, Denmark, France, Spain and the United States, he said. Bangkok Post

Delta sub-variants detected, but not of special concern

People seek testing for Covid-19 in Nong Chok district of Bangkok on Monday. (Photo: Varuth Hirunyatheb)

The Delta variant of Covid-19 has spread to all 77 provinces, along with four sub-variants that have not shown themselves to be especially harmful mutations yet, a senior medical official said on Tuesday.

Dr Supakit Sirilak, director-general of the Department of Medical Sciences, said the Delta variant had spared Suphanburi province until this week, but had now been detected there.

It was now found in all provinces and was the dominant variant found in 93% of sampled Covid-19 cases nationwide.

He said widespread outbreaks of a variant naturally led to sub-variants. However, they were not Thai variants because they had been previously found in Britain, Denmark, France, Spain and the United States, he said.

The four sub-variants had not shown any particularly harmful characteristics, but health officials were monitoring their development, Dr Supakit said.

The Centre for Medical Genomics of Ramathibodi Hospital recently detected these four sub-variants:

• AY.4 (B.1.617.2.4) in four patients in Pathum Thani and one each in Kamphaeng Phet, Chiang Mai, Samut Prakan and Chon Buri between June and August
• AY.6 (B.1.617.2.6)  in a patient in Bangkok in July
• AY.10 (B.1.617.2.10) in one patient in Bangkok in July
• AY.12 (B.1.617.2.15) in a patient in Bangkok and two others in Surat Thani from July to August. 

Prof Emeritus Wasun Chatratita, head of the hospital's Centre for Medical Genomics, said the four sub-variants were detected among local infections, not in quarantined arrivals.

Researchers were studying whether they showed resistance to vaccines or were more contagious, he said.