Novel coronavirus is from the same family of viruses that caused Severe Acute Respiratory Syndrome that began in Asia in 2003, WHO officials said.
The human-on-human transmission to healthcare workers first occurred to a 45-year-old man who became ill on May 2 and is currently in a critical condition. A 43-year-old woman with a co-existing health condition became ill on May 8 is in a stable condition, WHO said.
Although healthcare associated transmission has been observed before with novel coronavirus in Jordan in April 2012, this is the first time healthcare workers have been diagnosed with the infection after exposure to patients.
"Healthcare facilities that provide care for patients with suspected novel coronavirus infection should take appropriate measures to decrease the risk of transmission of the virus to other patients and healthcare workers," WHO officials said in a statement. "Healthcare facilities are reminded of the importance of systematic implementation of infection prevention and control."
Since the beginning of May to date, a total of 21 patients, including nine deaths, have been reported from the outbreak primarily linked to a healthcare facility in the Eastern part of Saudi Arabia.
Since September, there have been 40 laboratory-confirmed cases of human infection with novel coronavirus, including 20 deaths from six countries: France, Germany, Jordan, Qatar, Saudi Arabia and Britain.