Measles: What you need to know
Measles can be easily prevented with safe and effective immunization, health officials say
Health officials in Toronto expressed concern recently after confirming four cases of measles, an extremely contagious virus that is easily prevented with immunization.
The four cases — two in children under the age of two and two adults — are unconnected and have no known source, suggesting measles was contracted in the city instead of abroad.
Measles is one of the leading causes of death among young children worldwide, according to the World Health Organization, but is rare in Canada.
Since the introduction of a vaccine in the 1960s, the number of cases in Canada has declined dramatically. Between 1924 to 1958 there were 3,700 cases of measles per 1,000,000 population, which declined to less than three cases per 1,000,000 population between 1998 and 2013.
Here are some commonly asked questions about measles.
What is measles?
Measles, also known as rubeola or red measles, is a highly contagious virus.
It can infect anyone who has not been immunized or who has not previously had measles. It would be very unusual for an individual to have lab-confirmed measles more than once. Generally, once you have had measles you are protected for life.
Persons born before 1970 are generally considered immune.
What are the symptoms?
Symptoms of measles can begin seven to 18 days after exposure and initially include fever, cough, runny nose, sleepiness, irritability and red eyes. A red blotchy rash that develops on the face and spreads down the body appears three to seven days later.
How is it spread?
Measles is an extremely contagious virus that spreads easily from person to person.
A person is contagious roughly four days before the rash appears until four days after.
Measles is spread through direct contact, through the air when a person coughs or sneezes, and by touching objects that were recently exposed to infected mucus or saliva. Measles can survive up to two hours in the air, even if the contagious person has left the space.
How is it treated?
There is no treatment for measles and most people recover within two to three weeks. A doctor can prescribe medication, including pain relievers, to reduce fever. The Public Health Agency of Canada recommends people drink lots of fluids, eat healthy foods and get plenty of rest.
However, it can be dangerous, leading to brain swelling, known as encephalitis, pneumonia and hearing loss. The Public Health Agency says between two and three out of every 1,000 cases of measles is fatal in developed countries.
How is it prevented?
Measles can be prevented with two doses of vaccine, including the measles-mumps-rubella (MMR) immunization or measles-mumps-rubella-varicella (MMRV) immunization.
The needle vaccine is given to children first between the ages of 12 to 15 months and again at 18 months or four to six years depending on the province or territory.
Public Health says the vaccine is safe, effective and free. There can be some mild side-effects, however, including redness or soreness where the needle went in, as well as slight fever, skin rash and swollen glands.
If there is any doubt about your immunization history, health officials recommend you get the vaccine.
A single dose is considered to have up to a 95 per cent effectiveness rate, which rises to 99 per cent with the two doses recommended.
What should you do if you think you have measles?
If you are showing symptoms and think you have measles, see a doctor as soon as possible. However, the Public Health Agency says you should call ahead and explain your symptoms so your health provider can limit exposure to others.
If you get measles, you should stay at home until four days after the rash appears so you don’t infect anyone else.
Are vaccines safe?
There are a number of common misconceptions about vaccines, including that they contain dangerous substances or can overwhelm a child’s immune system.
However, vaccines are continuously monitored and tested to make sure they are effective and safe, the Public Health Agency says.
Perhaps one of the more persistent myths about vaccines is that they can lead to autism, owing in part to a 1998 study that has since been debunked and retracted.
“Medical researchers and scientists around the world have studied information collected over many years to see whether there is a link between the MMR vaccine and autism — a lifelong developmental disorder. They have not found any evidence of a link,” the Public Health Agency says on its website.
How many people in Canada get vaccinated?
When the Public Health Agency validated its national immunization coverage survey against local immunization records in 2011, it found 95.2 per cent had received at least one dose of measles-containing vaccine by two years of age and 94.9 per cent had received at least two doses by seven years of age.