China has given conditional approval for a single dose Covid-19 vaccine, touted to be a rival to Johnson & Johnson’s one-jab shot cleared by the US drug regulator on Sunday. The Chinese vaccine was rolled out on Friday, the state-run Global Times reported on Sunday. It is the only single-dose Covid-19 vaccine that has been given conditional approval to be rolled out in China. The vaccine's effect kicks in after 14 days of inoculation and the protective effect can last at least six months after a single-dose. It can increase immune response by 10 to 20 times if the second dose is taken half a year after the first one, the report said.