Singapore scientists testing a Covid-19 vaccine from US firm Arcturus Therapeutics plan to start human trials in August after promising initial responses in mice. More than 100 vaccines are being developed globally, including several already in human trials from the likes of AstraZeneca and Pfizer, to try and control a disease that has infected more than eight million people and killed over 430,000 worldwide.
The vaccine being evaluated by Singapore’s Duke-NUS Medical School works on the relatively-untested Messenger RNA (mRNA) technology, which instructs human cells to make specific coronavirus proteins that produce an immune response. “The fact that it replicates and triggers a very balanced immune response, both in terms of the antibody and killer cells … those are welcome properties,” Ooi Eng Eong, deputy director of the school’s emerging infectious diseases programme, told Reuters. Antibodies stick to the virus and prevent it from infecting cells, while killer cells, another arm of the immune system, recognise infected cells and destroy them, he said.
The mRNA approach has not yet been approved for any medicine so its backers, which also include US biotech firm Moderna, are treading uncharted territory. Because of that, Ooi said longer studies are needed to ensure its safety. “The most optimistic case is that it’s about this time next year that we will have a vaccine,” Ooi said.
Ooi is also working on a monoclonal antibody treatment for Covid-19 and will begin safety trials on healthy people this week before testing on Covid-19 patients in the coming months. Ooi said potential deployment of the treatment could be faster than the vaccine, without giving an exact timeline. Antibodies are generated in the body to fight off infection. Monoclonal antibodies mimic natural antibodies and can be isolated and manufactured in large quantities to treat diseases. Singapore has one of the highest infection tallies in Asia, with more than 40,000 cases, largely due to mass outbreaks in dormitories of its migrant workers.