CHP reports investigation of leprosy case

     The Centre for Health Protection (CHP) of the Department of Health (DH) today (June 21) reported an investigation of a leprosy case, and reiterated that the transmission risk of leprosy in Hong Kong is low and the disease does not spread easily among people.

     The case involved a 30-year-old woman with good past health, who developed a skin rash on her arm since early May. She attended Tseung Kwan O Hospital for medical attention on May 23 and was admitted for treatment. Her skin biopsy specimen was positive for leprosy upon laboratory testing. She is in stable condition. Initial enquiries by the CHP revealed that the patient stayed in the Philippines during the incubation period before arriving in Hong Kong in late April. Her home contacts in Hong Kong are currently asymptomatic and under medical surveillance. Further assessments will be provided for the home contacts. The CHP's investigations are ongoing.

     Leprosy (Hansen's disease) is a chronic infectious disease caused by Mycobacterium leprae which can be transmitted by nasal droplets or by close skin contact.

     A spokesman for the CHP stressed that the disease will only be transmitted through prolonged and close contact over months to years with leprosy patient not being treated at all. The disease does not spread easily between people through casual contact with a leprosy patient, such as shaking hands or hugging, sharing meals or sitting next to each other. Also, the disease does not spread through sex or pass to the fetus during pregnancy. The patient stops transmitting the disease as soon as they started treatment.

     The disease affects the skin, the peripheral nerves, mucosa of the upper respiratory tract, and the eyes of infected persons. Symptoms may occur within one year after infection but can also take as long as 20 years or even more to occur. Without treatment, loss of sensation and disability can occur. The spokesman reiterated that leprosy is curable and early treatment can prevent disability. Antibiotics used for effective treatment of leprosy in form of multi-drug therapy (rifampicin, clofazimine and dapsone) are readily available in Hong Kong.

     Leprosy is a notifiable infectious disease in Hong Kong. The number of cases reported has declined significantly from above 100 in the early 1970s to between 20 and 30 in the early 1990s. This can be attributed to improvements in the health of the general population and better health and sanitation facilities. The number of cases reported ranged from one to nine cases annually between 2014 and 2023. Among them, the majority (above 80 per cent) were imported cases with a history of prolonged stays outside Hong Kong, and the remaining cases were either relapses of past infections or older adults who acquired the infection decades ago. Among the new cases, none were found to lead to disabilities. The CHP will continue to monitor the situation.

     Globally, according to the World Health Organization (WHO), leprosy occurs in more than 120 countries, with more than 200 000 new cases reported every year. Although there has been a gradual reduction in the number of cases globally, Brazil, India and Indonesia still reported more than 10 000 new cases each year from 2018 to 2022, while some countries like the Philippines, Nepal, Myanmar, etc reported 1 000 to 10 000 new cases each year during the same period. Therefore, early diagnosis, especially for people with prolonged stays in leprosy prevalent countries, is crucial.

     According to the WHO, there is strong evidence that Bacillus Calmette–Guérin (BCG) vaccination is effective in preventing leprosy and has contributed to the decline in the incidence of the disease globally. In Hong Kong, BCG is given at birth with very high coverage rates approaching 100 per cent all along. With the high coverage of BCG vaccine in the local population and being a disease that does not spread easily among people, the transmission risk of leprosy in Hong Kong is low. 

     For more information, please visit the CHP webpage featuring leprosy at (www.chp.gov.hk/en/healthtopics/content/24/107984.html).