SHANGHAI: Doctors in Shanghai are using infusions of blood plasma from people who have recovered from the coronavirus to treat those still battling the infection, reporting some encouraging preliminary results, a Chinese professor said on Monday.

The coronavirus epidemic is believed to have originated in a seafood market in the central city of Wuhan, capital of Hubei province, and has so far killed 1,770 people and infected more than 70,000 in mainland China.

China’s financial hub of Shanghai on Monday had 332 infected cases, one of whom died in recent weeks. Lu Hongzhou, professor and co-director of the Shanghai Public Health Clinical Centre, said that 184 cases were still hospitalised, including 166 mild cases, while 18 were in serious and critical conditions.

He said the hospital had set up a special clinic to administer plasma therapy and was selecting patients who were willing to donate. The blood would be screened to check if he or she had other diseases like hepatitis B or C, he added.

“We are positive that this method can be very effective in our patients,” he said.

There are no fully licensed treatments or vaccines against the new coronavirus, and the process of developing and testing drugs can take many months and even years.

As well as using plasma therapies, which harness antibodies in the blood of someone who has fought off the viral infection, doctors are also trying antiviral drugs licensed for use against other infections to see if they might help.

Chinese scientists are testing two antiviral drugs and preliminary results are due in weeks, while the head of a Wuhan hospital had said plasma infusions from recovered patients had shown some encouraging preliminary results.

More than a dozen infected Americans from a coronavirus-riddled cruise ship off Japan flew on evacuation flights to the US with other passengers on Monday, as the epidemic claimed more lives in China to take the death toll above 1,700.

With fresh cases emerging daily in Japan, the government has advised citizens to avoid mass gatherings, and cancelled public events — including annual celebrations in central Tokyo for the Emperor’s birthday and the amateur portion of the city marathon, affecting around 38,000 runners.

Beijing’s municipal authorities have ordered everyone arriving in the capital to self-quarantine for 14 days, the presumed incubation period of the virus. State media said China may postpone its annual parliament session, which has been held in March for the last 35 years.