One of the world's leading Covid-19 experimental vaccines produces an immune response in both old and young adults, raising hopes of a path out of the gloom and economic destruction wrought by the novel coronavirus.

“It is encouraging to see immunogenicity responses were similar between older and younger adults and that reactogenicity was lower in older adults, where the Covid-19 disease severity is higher,” an AstraZeneca spokesman said.

“The results further build the body of evidence for the safety and immunogenicity of AZD1222,” the spokesman said, referring to the technical name of the vaccine.