A woman in her 50s has become Australia’s third case of human-to-human transmission of coronavirus.

NSW Health confirmed the woman had not travelled abroad recently and contracted the virus from another carrier, bringing the total number of infections statewide to 15.

It comes as two more people in NSW tested positive to COVID-19 overnight, adding to the four others who were diagnosed in the past 24 hours.

A NSW Health spokesperson described the recent increase of cases as “rapid”.

Details have also been released of the five Sydney-bound flights which had passengers who were later confirmed as having contracted the virus, including a man from Iran who tested positive overnight.

Premier Gladys Berejiklian warned the number of cases is likely to go up in the next few days.

“What is scary on this situation is that the vaccine is not yet developed but we ask everybody to stay calm, to go about business and to stay updated the NSW health website is giving our citizens in NSW timely information,” she told Nine’s Today Show on Wednesday.

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Meanwhile, a 53-year-old male doctor who tested positive Monday afternoon after contracting the virus from a patient is in a stable condition at Westmead Hospital.

The health worker is “going quite well”, NSW Health Minister Brad Hazzard told the Nine Network on Tuesday.

NSW Chief Health Officer Dr Kerry Chant said he had worked at Ryde Hospital and had been in contact with a “diverse range of patients”.

Thirteen doctors, 23 nurses and four other health workers have been identified as close contacts of the doctor and are in home isolation.

A further eight patients of the doctor are showing no symptoms, while 29 other patients identified as casual contacts are being chased up.

COVID-19 infects three new countries

Indonesia reports two cases of COVID-19. Photo: Getty

The coronavirus has spread to Ukraine, Morocco and Indonesia as global infections surge past 92,000 and the death toll exceeds 3100.

The number of cases in Italy, alone, jumped to 2502 from 2036 the previous day, resulting in a 22-per-cent spike in infections.

Of the total, 79 patients have died and 160 have recovered from the virus.

Some 1263 people are in hospital, including 229 under intensive care, while 1000 have mild symptoms or none at all and are expected to shake off the virus under isolation at home.

Meanwhile, a coughing Pope Francis, who canceled his attendance at a week-long Lenten retreat because of a cold, has been confirmed as not suffering from “symptoms related to other pathologies”, spokesman Matteo Bruni said in a statement.

Pope Francis wipes his nose during the Ash Wednesday mass which opens Lent last week. Photo: Getty

About 3.4 per cent of reported coronavirus patients have died, World Health Organisation chief Tedros Adhanom Ghebreyesus said in Geneva.

As a percentage, seasonal flu, which infects hundreds of thousands each year worldwide, kills far fewer.

But the coronavirus outbreak could be controlled, he said.

“To summarise, COVID-19 spreads less efficiently than flu, transmission does not appear to be driven by people who are not sick, it causes more severe illness than flu, there are not yet any vaccines or therapeutics, and it can be contained.”

President Donald Trump said he was considering suspending travel to “badly affected” counties.

“We don’t want to do that, but we’re looking at other countries and we’re being very stringent,” he said.

“We’re watching Italy very closely, South Korea very closely, even Japan very closely, and we’ll make the right determination at the right time.”

Mr Trump promised to donate his salary from the last quarter of 2019 to the Department of Health and Human Services which has been working on controlling the spread.

President @realDonaldTrump made a commitment to donate his salary while in office. Honoring that promise and to further protect the American people, he is donating his 2019 Q4 salary to @HHSGov to support the efforts being undertaken to confront, contain, and combat #Coronavirus. pic.twitter.com/R6KUQmBRl1

— Kayleigh McEnany 45 Archived (@PressSec45) March 3, 2020

His comments came after the US Centers for Disease Control and Prevention expressed serious concern that the country was on the brink of a larger, uncontained outbreak.

“What is happening now in the United States may be the beginning of what is happening abroad,” Nancy Messonnier, director of CDC’s National Center for Immunization and Respiratory Diseases, told reporters.

“We will continue to maintain, for as long as practical, an aggressive national posture of containment. That said, you might see some local communities taking specific actions to mitigate the disease.”

-with AAP