The World Health Organization said current evidence has showed airborne transmission is not the primary mode for the novel coronavirus, and the principal transmission method is still thought to be respiratory droplets and close contact with an infected person.

The virus has also originated from animals, and genetic analysis shows that it may come from bats and the intermediate hosts are still unknown, according to the China-WHO COVID-19 joint survey report published on Saturday.

In China, person-to-person transmission of the virus primarily occurred between family members, it said. Of the 1,836 confirmed cases in Guangdong and Sichuan provinces found at the time of the survey, 1,308 took place in families.

Scientists from Jilin University First Hospital reported they found small traces of the novel coronavirus on the surfaces of objects in its nurse stations in quarantined areas, as well as in the air of intensive care units. The paper was published on the non-peer-reviewed preprint server medRxiv on Thursday.

While the samples that tested positive for the virus are small, only two out of 158 objects and air samples, scientists suggest that hospitals should enhance sanitation and supervision efforts to reduce the risk of patients and staff getting infected.