Thailand has reported five new COVID-19 cases involving Thais returning from abroad and zero fatalities over the last 24 hours, bringing the tally to 3,156 infection cases with 58 fatalities.

Today marks 29 days without local transmission in the kingdom.

Centre for COVID-19 Situation Administration (CCSA) assistant spokeswoman Dr Panprapa Yongtrakul said five asymptomatic patients aged 22 and 52 had returned from Egypt and Qatar.

Of 3,156 COVID-19 cases, 75 remain warded in hospitals, she said.

Meanwhile, Thai researchers are making positive progress in the trials of COVID-19 vaccine.

Minister of Higher Education, Science, Research and Innovation, Suvit Maesincee said the first dose of vaccine to monkeys on May 23 showed encouraging results.

He said second dose exercise started yesterday (Monday).

"After the first injection on monkeys on May 23 using the mRNA-type of vaccine, all the animals remained healthy and suffered no side-effects from the jabs. We also found an increased amount of antibodies in their blood.

"We are looking for another positive result that will lead to human trial in October," he said as quoted by Bangkok Post.

The vaccine has been jointly developed by Chulalongkorn University's Centre of Excellence in Vaccine Research and Development, the National Vaccine Institute and the Department of Medical Sciences.

To date, more than 100 potential vaccines for COVID-19 have been developed worldwide with Thailand joining the race to develop its own vaccine as well.

-- BERNAMA