CHP investigates local measles case epidemiological linked to earlier measles cases
The Centre for Health Protection (CHP) of the Department of Health (DH) today (April 20) is investigating a local measles case epidemiologically linked to earlier measles cases. In response to the global rise in measles cases and the recent consecutive infections of three individuals working at the airport, the CHP once again urged airport staff and foreign domestic helpers to receive the measles vaccine to protect their health and prevent the virus from spreading in the community.
The latest case involves a 37-year-old male working at the airport. He has developed a fever and myalgia since April 15, followed by a cough and a sore throat the next day. He attended a private clinic in Tuen Mun on April 16 and 18. The patient developed a rash on the evening of April 18. On the following day, the CHP arranged for him to beadmitted 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 remains hospitalised and is in stable condition.
An epidemiological investigation revealed that the patient worked for the same company at the airport as the two measles cases previously announced by the CHP. The patient lives alone and is uncertain whether he has received measles vaccination. The CHP believed that it is highly likely that the patient was infected at his workplace. The three cases are epidemiologically linked.
During the patient's communicable period (since April 14), in addition to visiting the private clinic on April 16 and 18, he also went to work at the airport on April 15 and 19. The CHP has been carrying out contact tracing to identify any close contacts and high risk individuals. As of 5pm today, a total of 31 individuals who stayed in the same clinic with the patient during the same time period and 68 relevant staff at his workplace were identified as close contacts.
The health booth set up by the CHP at the airport has provided assessment and vaccination for over 200 staff working at the airport since April 18. The health booth will continue to operate until Wednesday (April 22), with service hours from 10am to 5pm.
The CHP will continue to investigate and follow up on the cases, and put the close contacts under medical surveillance.
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. So far this year, about 1 750 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 407 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 236 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 27 and 92 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.
In response to the global rise in measles cases and the risk of imported cases, the CHP has sent a letter to all doctors in Hong Kong to inform them of the latest situation regarding measles and urged them to remain vigilant and report any suspected cases. At the same time, the CHP has also sent letters to foreign domestic helper agencies and the aviation industry, encouraging foreign domestic helpers and airport staff to receive the measles vaccine to protect their health and prevent the spread of the virus in the community.
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.
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 website of the DH's Travel Health Service for news of measles outbreaks outside Hong Kong.
Photo source: reference image
