CHP investigates imported measles case epidemiologically linked to earlier case
The Centre for Health Protection (CHP) of the Department of Health (DH) today (December 24) is investigating an imported measles case. The patient is the mother of the imported measles case announced yesterday (December 23). The CHP reminded members of the public who are non-immune to measles to ensure that they have completed two doses of measles vaccination before travelling to reduce the risk of infection.
The latest case involves a 22-year-old woman who developed fever on December 18 with no other symptoms and did not seek medical attention. As her son tested positive for the measles virus upon nucleic acid testing, the CHP found that the female patient developed symptoms during contact tracing and epidemiological investigation. She was then arranged to admit to hospital for testing. Her clinical specimen was tested positive for the measles virus upon nucleic acid testing. She is isolated for treatment at the Princess Margaret Hospital and is currently in stable condition.
The female patient stayed outside Hong Kong from October 1 to December 16. As she spent the whole incubation period outside Hong Kong, the case was classified as an imported case. An epidemiological investigation revealed that the female patient did not receive measles vaccination.
As the abovementioned two epidemiologically linked patients have visited a private clinic on December 19, the CHP has reached contacts who visited the private clinic during the same period on December 19, to identify if high risk persons were involved, and assessed if they had immunity against measles and arranged vaccinations for contacts who are non-immune. So far there are no pregnant women, persons with weakened immunity and infants under one year old among the contacts. The contacts did not present measles symptoms. The CHP will continue to put the relevant contacts under medical surveillance. Management of relevant private clinic was requested to report to the CHP if any persons develop measles symptoms for follow up.
The CHP's investigation is ongoing.
"Measles remain as an endemic infection in many places around the world. The number of measles cases in some overseas countries has been increasing recently. The outbreaks in North America (including the United States and Canada), Europe and Southeast Asia areas (including Vietnam, Cambodia and the Philippines) are ongoing due to the relatively low vaccination rate. Furthermore, an increasing number of measles cases have also been recorded in Japan and Australia this year. Overseas cases mainly affected people who were unvaccinated or had unknown vaccination status. This shows the importance of maintaining a high vaccination rate and herd immunity within the community. For those who plan to travel to areas with measles transmission, they should check their vaccination records and medical history as early as possible. If they have not been diagnosed with measles through laboratory tests and have never received two doses of measles vaccine or are not sure if they have received a measles vaccine, they should consult a doctor at least two weeks prior to their trip for vaccination. Pregnant women and women preparing for pregnancy who are non-immune to measles as well as children aged under one year who are not due for the first dose of Measles, Mumps and Rubella (MMR) combined vaccine under theHong Kong Childhood Immunisation Programme, are advised not to travel to places with outbreaks of measles," the Controller of the CHP, Dr Edwin Tsui, said.
"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 the healthcare workers so that appropriate infection control measures can be implemented at the healthcare facilities to prevent any potential spread," Dr Tsui added.
"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," he continued.
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:
For more information on measles, the public may visit the CHP'smeasles thematic page. Members of the public who are going to travel can visit the website of the DH'sTravel Health Servicefor news of measles outbreaks outside Hong Kong.
Source: AI-found images
