A US firm has said it will soon start final-stage human trials for a possible vaccine.
The vaccine developed by the US pharmaceutical company Moderna has proved safe and provoked immune responses in all 45 volunteers in phase-one trials.
The last stage of the trials is expected to begin later this month and will involve recruiting 30,000 participants in the US.
Half will receive the vaccine, while the other half are given a placebo.
Researchers will then track them over two years to determine whether they are protected against infection by the virus.
Or, if they do get infected, whether the vaccine prevents symptoms from developing.
The study should run until October 2022 but preliminary results should be available long before.
Moderna was the first company to start human testing of a vaccine back in March.