Measles is a highly infectious disease caused by a virus.
Affected persons present initially with fever, cough, runny nose, red eyes and white spots inside the mouth. This is followed 3 to 7 days later by a red blotchy skin rash, which usually spreads from face to the rest of the body. The rash usually lasts 4 - 7 days, but can persist for up to 3 weeks leaving with brownish staining and sometimes fine skin peeling.
In severe cases, lung, gut and brain can get involved and lead to serious consequences or even death.
Measles can be transmitted airborne by droplet spread or by direct contact with nasal or throat secretions of infected persons, and less commonly, by articles soiled with nasal or throat secretions. The patient can pass the disease to other persons from 4 days before to 4 days after the appearance of the rash.
To prevent getting measles, members of the public are advised to observe the following:
Measles remain as an endemic infection in many places around the world. Many countries in the world are experiencing resurgence of measles with outbreaks reported recently, including countries in Europe and in South East Asia. Travellers should pay attention to the risk of measles. For outbreak news of the affected areas, please refer to the website of Department of Health's Travel Health Service.
Vaccination against measles is the most effective way to prevent the disease. For those who had received two doses of measles-containing vaccine or confirmed to have measles infection in the past are considered to be immune to measles. People who intend to travel to areas with recent measles outbreak are advised to review their vaccination history and past medical history. Non-immune individuals are advised to consult their doctors about measles vaccination, which is usually given together with mumps and rubella vaccines as MMR vaccine.
For those with incomplete vaccination, unknown vaccination history or unknown immunity against measles, they are advised to consult their doctor for advice on measles vaccination. As it takes about two weeks after vaccination for antibodies to develop and provide protection against measles, travellers are advised to plan and get vaccinated ahead.
According to the United States Centers for Disease Control and Prevention, when given as scheduled, two doses of MMR vaccine are 97% effective while one dose is 93% effective against measles. In Hong Kong, children receive a two-dose course of measles vaccination under the Hong Kong Childhood Immunisation Programme.
Local children aged under one year are not due for MMR vaccination under the Hong Kong Childhood Immunisation Programme. As they are susceptible to measles, they are advised not to travel to areas with recent measles outbreak. If people must travel to areas with measles outbreak with children under one year, they have to consult their doctor for advice.
Pregnant women and women preparing for pregnancy should consult their doctor for advice if they are not sure whether they are immune to measles. Since measles-containing vaccines cannot be given during pregnancy, they are advised not to travel to areas with outbreaks or high incidence of measles if they are not immune to measles.
If travellers returning from affected areas 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. They should also report their symptoms and travel history in advance to the healthcare workers so that appropriate infection control measures can be implemented at the healthcare facilities to prevent any potential spread.
Those who might have had contact with the patients during the period of communicability are urged to observe if they have developed measles-related symptoms, and to seek medical treatment immediately if such symptoms appear. If they need to visit any health care facilities during the period of medical surveillance, they should also report whether they have symptoms and prior measles exposure history to the healthcare workers so that appropriate infection control measures can be implemented at the concerned healthcare facilities to prevent any potential spread.
All foreign domestic helpers who are non-immune* to measles should receive MMR vaccine, preferably before they arrive in Hong Kong. If this is not possible, they can consult a doctor after they have arrived in Hong Kong. Employment agencies can consider adding assessment of immune status against measles or MMR vaccination of foreign domestic helpers as additional items in the pre-employment medical check-up package.
*In general, people can be considered as non-immune to measles if (i) they did not have measles infection confirmed by laboratory test before, and (ii) they had not been fully vaccinated against measles or have unknown vaccination status.
For details about measles-containing vaccines provided by the Government, please refer to infographic Learn more about measles vaccine.
In general, the following individuals should NOT receive MMR vaccine^*:
^Medical advice should always be sought.
*According to information from the World Health Organization and the United States Centers for Disease Control and Prevention, anaphylactic reactions to MMR vaccines are not associated with hypersensitivity to egg antigens but to other components of the vaccines (such as gelatin). The risk for serious allergic reactions following receipt of these vaccines by egg-allergic persons is extremely low. Therefore, individuals with non-anaphylactic egg allergy can be safely vaccinated with MMR vaccine. Those with severe allergic reaction (e.g. anaphylaxis) to eggs should consult a healthcare professional for vaccination in an appropriate setting.
#In general, women should avoid pregnancy for three months after receipt of MMR vaccine and take appropriate contraceptive measure.
Measles infection in pregnancy can result in adverse pregnancy outcomes, including pregnancy loss, preterm birth, and low birth weight, but there is no evidence to support an increased risk of congenital defects. Moreover, neonates who get infected because the mother had measles shortly around the period of delivery are at an increased risk of subacute sclerosing panencephalitis (a very rare but fatal disease of the central nervous system) in later life.