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.

 China's first Ad5-nCoV COVID-19 vaccine was rolled out on Friday, the state-run Global Times reported on Sunday.

 Phase-I clinical trials of the vaccine started on March 16, last year, making it the world's first COVID-19 candidate vaccine that entered clinical trials, it said.

 It is the only single-dose COVID-19 vaccine that has been given conditional approval to be rolled out in China, the report quoted last Friday's story by the state broadcaster China Central Television (CCTV).

People can get desirable protective effect after 14 days of inoculation.

The protective effect can last at least six months after a single-dose inoculation and 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.

 With this, China's medical products regulator has approved five coronavirus vaccines which include Sinovac, Sinopharm, CanSinoBio and another by Wuhan Institute of Biological Products.

One of the developers of the Ad5-nCoV vaccine said that the annual production capacity can reach 500 million doses, which means 500 million people can be vaccinated in a year.

Phase-I clinical trials of the vaccine started on March 16, 2020, making it the world's first COVID-19 candidate vaccine that entered clinical trials, the Global Times report said.

Though China has been supplying its vaccines to different countries, none of them have been approved by the World Health Organisation (WHO).