An engineer shows an experimental vaccine against COVID-19 (Photo: AFP)

Dr Suchinda Malaivitjitnond, Director of the National Primate Research Center of Thailand, said the testing phase on the macaque monkeys came after trials on mice were successful.

They are working in collaboration with the University of Pennsylvania in the US using a new technology based on mRNA, a type of genetic material never used before to make a vaccine.

Thailand was the first country outside China to detect an infection in mid-January. It has so far reported over 3,000 cases and 57 deaths.

Meanwhile, Malaysia reported 172 additional infections on May 25, rising nearly threefold compared to the previous day. It was the highest daily jump and the first day of three-digit increase of infections in the country in the last three weeks.

So far, the country reported a total 7,417 cases, with 115 fatalities. Some 5,979 patients have recovered, accounting for 80.6 percent./.