The Centre for Health Protection today said it is investigating three additional cases of novel coronavirus infection, taking the number of confirmed cases in Hong Kong to 24.

The centre said according to preliminary investigations, some of the confirmed cases are believed to be locally infected.

The first case involves a 55-year-old woman with good past health who is the wife of the 21st confirmed case.

She had developed a sore throat since February 1, and a fever and diarrhoea from February 2.

The woman had consulted a private doctor before seeking treatment at Princess Margaret Hospital on February 4. She went back to the hospital the next day and was admitted for isolation and management. She is in a stable condition.

The patient departed for Tokyo, Japan with her husband on January 28, and took Hong Kong Express Airways flight UO 651 on February 1 and arrived home on February 2.

Passengers on board that return flight are urged to call the centre’s hotline at 2125 1122 which runs from 8am to midnight daily.

The taxi drivers who drove the couple or the patient from February 2 to 5 should also call the hotline.

Quarantine will be arranged for the patient's other home contacts - her parents-in-law and domestic helper - who are asymptomatic.

The second case involves a 63-year-old woman with good past health. She had developed a cough and malaise since January 26.

She had consulted a Chinese medicine practitioner and a private doctor before seeking treatment at Pamela Youde Nethersole Eastern Hospital on February 5. She was admitted on the same day and is in a stable condition.

The patient lives in Ko Mong Building, Shau Kei Wan. She visited her husband who lives in Lai To Home For The Aged in Sai Wan Ho during the incubation period and after the onset of symptoms. She had no travel history during the period.

Her husband, as well as her son and granddaughter who live with her, are asymptomatic and quarantine will be arranged for them.

The third case involves a 65-year-old woman with underlying illnesses. She had developed a fever and cough since January 28.

She consulted a private doctor before seeking treatment at Prince of Wales Hospital on February 5, where she was admitted for management. She is in a serious condition.

The patient lives alone in Sui Shek House, Shek Mun Estate in Sha Tin and had no travel history during the incubation period.

The taxi driver who drove the patient from Hilton Plaza, Sha Tin to Prince of Wales Hospital around 12.15pm to 1pm on February 5, is urged to call the centre’s hotline.

The centre called on the public to maintain strict personal and environmental hygiene, which is key to personal protection against infection and prevention of the disease’s spread in the community.

It will update reported novel coronavirus infection cases on its dedicated webpage.