SINGAPORE - United States-based Arcturus Therapeutics, which is jointly developing a Covid-19 vaccine with the Duke-NUS Medical School in Singapore, is preparing to test a single low-dose shot of its messenger RNA vaccine in large trials that will start in the second quarter of the year.

The 5 microgram single-dose regimen will also be a lyophilised, or freeze-dried, version that will be easier and less costly to distribute and store. It will not require the cold chain storage and transport that the usual mRNA vaccine in frozen liquid form needs.