Last updated on July 20, 2021.
Since the beginning of 2019, there has been a large number of new measles cases around the world. This outbreak has alarmed the public and especially people traveling. In Hong Kong, the majority of the reported measles cases involve people who work or transit through the Hong Kong airport (pilots, flight attendants, baggage handlers, custom officers…). By April 29, the number of people affected by measles in Hong Kong this year reached 75.
Healthy Matters brings you a doctor-reviewed guide to measles in Hong Kong so you can better protect yourself and your loved ones.
What are the symptoms of measles?
Usually, measles will start with high fever (around 40C or 104F) and will last 4 to 7 days. Then you may develop the following symptoms:
- Red and watery eyes that might be sensitive to light
- Swollen eyelids
- Runny nose
- Very small white-grey ish bumps inside your mouth (the Koplik spots)
- A cough
Around 2 to 4 days after the first symptoms, the measles rash will appear. It will last about 1 week. It will usually first appear on the hairline or the neck and will spread through the rest of the body.
The rash is a very typical feature of measles. It looks like small red to brown flat spots that may come together into larger patches and they might be itchy.
Why is measles so contagious?
The measles virus is located in the mucus from the throat and nose. This means infected people will spread it by simply talking or coughing. The virus will then stay active for 2 hours in the air or on the surface where it was spread. Any person touching an infected surface or breathing the infected air during that window of time, will have a 90% chance of being infected if they haven’t been immune.
Once someone has been in contact with the virus, the incubation period usually ranges from 7 to 18 days.
Why is measles considered so seriously?
Measles can be a very serious disease, with 30% of reported cases experiencing one or more complications. In the US, death occurs in 2-3 per 1,000 cases.
Here is a list of the most common complications that may occur:
- Diarrhea (most common: 8% cases especially young children)
- Ear infection (7% cases)
- Infection of the lungs and airways (bronchitis, pneumonia, croup – 6% cases)
- Inflammation of the voice box (laryngitis)
- Febrile seizures caused by the fever
Here is a list of the less common, but most serious, complications that may occur:
- Hepatitis (liver infection)
- The virus might cause brain and spinal cord infection (encephalitis and meningitis)
Who is most vulnerable to measles?
If a pregnant woman is not immune to measles, there are serious risks for her baby. The major risks are:
- The baby might be born early (before the 37th week of pregnancy)
- The baby might have a low birth weight
- Miscarriage (before 24 weeks of pregnancy)
- Stillbirth (after 24 weeks of pregnancy)
Children below one year of age:
Children less than 1 year old are more likely to get infected since they have not been vaccinated yet or only had one injection.
People with impaired immunity:
People suffering from diseases impairing immunity might not be able to fight the virus. Hence there are more likely to present one of the serious complications mentioned above. People with AIDS, people who had transplants or cancer treatment should be very careful regarding measles.
How to treat measles?
Because measles is a virus, it cannot be treated with medicine. People with measles need bed rest and to drink plenty of fluids in order to help the body to fight it. The condition of the person affected will usually get better after 7 to 10 days.
When should you see your doctor?
If you suspect that you could have measles you should contact your doctor as soon as possible.
However, make sure to call your doctor ahead to explain the situation, in order to avoid going to his/her practice and accidentally spreading the virus to others.
The suspicion of being infected may come from only being in contact with someone having measles. This applies even if you do not have any symptoms yet and if you have any doubt about whether you are immune.
How is measles diagnosed?
Measles is diagnosed by a combination of the symptoms and blood tests by your doctor.
Can someone get measles more than once?
No, it is impossible. Once you had it, your body has developed the antibodies and you are therefore immune.
How to prevent measles? The Measles, Mumps, and Rubella (MMR) vaccine
The MMR vaccine remains the best way to prevent measles. It was introduced to Hong Kong in 1967, but at that time only one injection was done. Since 1996 two doses are recommended for better protection.
In Hong Kong, the first injection is done at 1 year old and the second at 6. However, due to the recent outbreak of measles cases, the Department of Health is considering administering the second dose at 18 months. This will help ensure early protection, according to the World Health Organisation. Other places such as Europe and Australia are already administering the first MMR at 12 months and the second at 18 months.
The Measles, Mumps and Rubella vaccine is 90-95% effective after the first dose and 97% effective after the second dose. It will take around 2 weeks after the vaccination for the body to develop the antibodies.
Be aware that pregnant women cannot get the vaccine.
How to prevent measles? Day-to-day advice?
- wash hands frequently especially after touching public installations, and before touching the nose, the eyes or the mouth.
- Cover the nose and mouth with a surgical mask when having respiratory symptoms.
- Children with measles should not go to school or any child-care centers until 4 days after the symptoms disappear.
- Adults with measles should avoid going to work and stay home until they are cured.
- Disinfect regularly surfaces that are touched frequently.
- Air your living space regularly.
- High-risk individuals (pregnant women, children, people with low-immune system) should consider wearing a surgical mask when going to poorly ventilated and crowded public spaces.
How are people in Hong Kong protected from measles?
People born before 1967:
The vast majority are immune to measles because most will have contracted measles in the course of their lives.
People born between 1967 and 1977:
There are more likely to not be immune because they may only have received one dose of the vaccine.
People born between 1978 and 1984:
They should be immune due to the Special Measles Vaccination Campaign carried by the Hong Kong Government in 1997. However, this was not mandatory.
People born in 1985 or after:
They received 2 doses of the MMR vaccine.
If you have any doubt about being immune or not, please consult your doctor for advice. It will be possible to do a measles serology test in a laboratory. In any case, having the vaccine again will not cause any harm.
What are the recommendations of the Health Department to contain the outbreak of measles cases in Hong Kong?
Because of the recent, rapid increase of measles cases, the Department of Health recommends the following:
- Every child above 1 year old should get the MMR vaccine.
- Those born in Hong Kong between 30 and 50 years old should receive a second injection of the MMR, or at least do a measles blood test in order to know if they are immune.
- In case of doubt about whether someone received the second injection, he or she should do a measles serology.
- Foreign domestic helpers who never contracted measles nor had the MMR vaccine should have at least the first injection of MMR as soon as possible and preferably 2 injections.
- Pregnant women and children under 1 year old should avoid traveling to the Philippines and Japan where there is a high chance of measles contamination.
- People with an impaired immune system should contact their doctor.
Some useful links:
Centre for health protection, Department of Health – Measles
Family Health Service, Department of Health – The MMR Vaccine
The Immunization Action Coalition – Measles Vaccine
Maternal Child Health Centre for your child
Reviewed by Dr. Mei Mei Yip 葉美美醫生. Doctor Yip works at OT&P Child Women and Health Clinic, Central. She trained and specialized in pediatrics at the University Pediatrics and Adolescent Unit at Queen Mary Hospital. She became a Member of the Royal College of Pediatrics and Child Health, UK in 2006. During this time, she also obtained her Diploma in Child Health and is certified for the Griffiths Mental Development assessment. She gained her Diploma in Advances in Medicine at the Chinese University of Hong Kong in 2014.