The coronavirus spreading in Myanmar is a different strain that spreads 20% faster than the original one in Wuhan, according to a doctor.

Dr Prasit Watanapa, from Siriraj Hospital, on Wednesday said around 60% of Covid-19 infections in Myanmar were caused by the G614 strain. The strain that spread in Wuhan last year was called D614.

He said society cannot be complacent after the recent news of vaccines being rolled out. "Don't pin your hopes on it, as it could take at least half a year for Thailand to gain access to Covid-19 vaccines," he warned.

In Tak, the provincial communicable disease committee has allowed Thai nationals in Myanmar to return to Thailand through legal border crossings since Dec 7 in a bid to deter illegal entry -- the cause of Covid-19 transmission recently.

Tak closed the border with Myanmar on March 21.

In Chiang Rai, the governor urged stranded Thais in Tachileik to visit the Township Border Committee in Myanmar and say they want to return to Thailand.

The governor said they would not be jailed but would be fined 1,800 baht per person for illegally entering Myanmar.

Around 400 Thais have been stranded in Myanmar.