The first human trial of a vaccine to protect against pandemic coronavirus has started in the US.
Four patients received the jab at the Kaiser Permanente research facility in Seattle, Washington, reports the Associated Press news agency.
The vaccine cannot cause Covid-19 but contains a harmless genetic code copied from the virus that causes the disease.
Experts say it will still take many months to know if this vaccine, or others also in research, will work.
The first person to get the jab on Monday was a 43-year-old mother-of-two from Seattle.