CHP investigates imported measles case
The Centre for Health Protection (CHP) of the Department of Health (DH) today (April 6) is investigating an imported measles case and reminds members of the public that vaccination is the most effective way to prevent measles.
The case involves a 30-year-old male who developed a fever, cough and runny nose on March 31. He sought medical attention from a private doctor on the following day (April 1). He attended the Accident and Emergency Department (AED) of the North Lantau Hospital (NLH) on April 4 due to persistent symptoms, where he was admitted for treatment. He developed a rash on the same day after admission, and was immediately transferred to Princess Margaret Hospital for isolation and treatment. His clinical specimen was tested positive today for the measles virus upon nucleic acid testing. The patient is in stable condition.
An epidemiological investigation revealed that the patient works at the airport. He was uncertain whether he had received measles vaccination. He travelled to Indonesia with a household contact during the incubation period. His household contact is asymptomatic to date. Since there are continuous measles outbreaks in Indonesia, the case was classified as an imported case. No epidemiological linkages have been established between the case and other confirmed cases previously recorded in Hong Kong.
During the patient's communicable period (i.e. since March 31), in addition to visiting a private clinic on April 1 and the AED of the NLH on April 4, he worked at the airport on April 3. The CHP has been carrying out contact tracing in the private clinic that the patient had visited, the NLH and his workplace to identify any close contacts and high risk individuals. As of 4pm today, a total of 21 individuals who stayed in the same clinic with the patient, nine patients in the NLH and 238 relevant staff at his workplace at the airport were identified as close contacts. The CHP will continue to conduct medical surveillance for the identified close contacts.
The CHP will continue to investigate and follow up on the case.
"Measles outbreaks are currently occurring in many regions around the world. North America (including the United States, Canada and Mexico) and Southeast Asia (including Indonesia, Cambodia and the Philippines) have seen persistent measles outbreaks in recent years due to low vaccination coverage rates. In the first three months of this year, about 1 600 cases have been recorded in the United States, a figure far higher than during the same period last year. In Europe, the number of measles cases in the United Kingdom and Italy has increased recently, with 336 and 84 cases recorded respectively since January this year. In Asia, the incidence of measles remains high in the Philippines, Indonesia and Cambodia. Japan has also seen a substantial rise in cases this year, with 152 cases recorded as of the end of March, which is higher than in the same period for the past six years. Singapore and Australia have reported 24 and 87 measles cases respectively this year, also higher than in the same period last year. Most of the overseas cases have affected people who were not vaccinated against measles or had an unknown vaccination status, which highlights the importance of maintaining a high vaccination rate and herd immunity within the community," said the Controller of the CHP, Dr Edwin Tsui.
"Despite the abovementioned case is identified as an imported case according to the epidemiological information, airport workers who come into frequent contact with international travellers are at higher risk of contracting measles amid the current global resurgence of the disease. They are strongly advised to review their vaccination history and past medical history, especially those born outside Hong Kong who may not have received measles vaccination during childhood. Individuals who have not received two doses of measles-containing vaccine, or those with unknown vaccination history, should consult their doctor as soon as possible for vaccination. The CHP will work with the Airport Authority Hong Kong to remind all airport workers and their employers of the importance of ensuring that airport staff are fully immune to measles," Dr Tsui added.
The incubation period of measles (i.e. the time from infection to onset of illness) is seven to 21 days. Symptoms include fever, skin rash, cough, runny nose and red eyes. If travellers returning from places with high incidence or outbreak of measles develop symptoms of measles (e.g. fever and rash), they should seek medical advice immediately and avoid contact with non-immune persons, especially pregnant women and infants under one year old. They should also report their symptoms and prior travel history to healthcare workers so that appropriate infection control measures can be implemented at the healthcare facilities to prevent any potential spread.
"Under the Hong Kong Childhood Immunisation Programme, the overall immunisation coverage in Hong Kong has been maintained at a very high level through the immunisation services provided by the DH's Maternal and Child Health Centres and School Immunisation Teams. As evidenced by the findings on vaccination coverage of primary school students and the territory-wide immunisation surveys conducted regularly by the DH, the two-dose measles vaccination coverage has remained consistently high, well above 95 per cent, and the local seroprevalence rates of measles virus antibodies reflect that most people in Hong Kong are immune to measles. However, Hong Kong, as a city with a high volume of international travel, still faces the potential risk of importation of the measles virus and its further spread in the local community. Hence, a small number of people who have not completed a measles vaccination (such as non-local-born people including new immigrants, foreign domestic helpers, overseas employees and people coming to Hong Kong for further studies) are still at risk of being infected and spreading measles to other people who do not have immunity against measles, such as children under 1 year old who have not yet received the first dose of the measles vaccine," Dr Tsui said.
People born before 1967 could be considered to have acquired immunity to measles through natural infection, as measles was endemic in many parts of the world and in Hong Kong at that time. People born in or after 1967 who have not yet completed the two doses of measles vaccination, or whose measles vaccination history is unknown, should consult their family doctors as soon as possible to complete the vaccination and ensure adequate protection against measles.
Besides being vaccinated against measles, members of the public should take the following measures to prevent infection:
- Maintain good personal and environmental hygiene;
- Maintain good indoor ventilation;
- Keep hands clean and wash hands properly;
- Wash hands when they are dirtied by respiratory secretions, such as after sneezing;
- Cover the nose and mouth while sneezing or coughing and dispose of nasal and mouth discharge properly;
- Clean used toys and furniture properly; and
- Persons with measles should be kept out of school till four days from the appearance of a rash to prevent the spread of the infection to non-immune persons in school.
For more information on measles, the public may visit the CHP's measles thematic page. Members of the public who are going to travel can visit the webite of the DH's Travel Health Service for news of measles outbreaks outside Hong Kong.
The Centre for Health Protection (CHP), Photo source: reference image
