Measles: Prevention and risks

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Why measles is still a risk

Measles is one of the most contagious diseases. Over 90% of people who are not immune to measles and who come into contact with the virus will become infected.

Measles can weaken a person's immune system by affecting the white blood cells, called lymphocytes. This leaves people more vulnerable to other infections for weeks or months, which can become serious.

In Canada, measles is relatively rare thanks to high vaccination rates across the country. However, Canada will continue to see measles cases and outbreaks as measles is present worldwide and travellers who are not vaccinated may bring measles back into Canada.

According to the World Health Organization:

  • 110,000 people died from measles in 2017
  • most of the deaths were children under 5 years of age
  • measles is the leading killer of children whose deaths could have been prevented by vaccines

Who is at most risk

If exposed to the measles, people who have not had the disease or who have not been vaccinated are at risk of getting sick. People at greatest risk of measles and its complications are:

  • unvaccinated young children
  • unvaccinated pregnant women
  • those with compromised immune systems

In Canada, adults born before 1970 are generally presumed to have developed natural immunity to measles.

Travellers who are not vaccinated may bring measles into Canada. As a result, outbreaks may occur, especially in communities where people are not vaccinated.

Individuals at higher risk of being exposed to measles include:

  • travellers
  • military personnel
  • healthcare workers
  • students

Preventing measles

Measles can be prevented with vaccination. The measles vaccine is safe, effective and free. With two doses, measles vaccination is almost 100% effective.

The measles-mumps-rubella (MMR) vaccine and/or the measles-mumps-rubella-varicella (MMRV) vaccine are usually given in childhood.

  • The first vaccine is usually given to children between 12 to 15 months of age.
  • The second vaccine is usually given before school entry. The vaccination schedules vary depending on your province or territory.

Side effects of this vaccine are usually very mild. Common vaccine side effects may include: sleepiness, swelling, soreness and redness where the shot was given. Also, unlike the severe symptoms of a natural measles infection, the weakened germs in the vaccine could result in a few spots on the skin or a mild to moderate fever. These mild symptoms are not dangerous and can actually demonstrate that the vaccine is working effectively to build immunity.

Prevention before traveling abroad

As measles is present in many parts of the world, travellers may be at increased risk. Protection against measles is especially important for people planning travel.

Travellers born before 1970 who are not immune to measles should get one dose of the measles vaccine.

As for travellers who were born in or after 1970 who are not immune to measles should get two doses of the measles vaccine.

Infants traveling can receive the measles vaccine as young as 6 months of age. However, two more doses of the measles-containing vaccine must be given after the child is 12 months old to ensure long-lasting immunity to measles.

If you are planning to travel abroad:

  • visit your healthcare provider at least 6 weeks before you leave
  • make sure your vaccinations are up to date for you and your family
  • read the Government of Canada's travel health notices

The best way to determine if you are fully protected against measles is to talk to a healthcare provider. They can interpret your age and vaccine history to determine whether you are already protected or what vaccines you might need.

Prevention during a measles outbreak

If there is a measles outbreak in your community and your vaccinations are not up to date, you are at risk of getting measles.

If this is the situation and you have been exposed to measles, you should speak to a healthcare provider.

A healthcare provider may recommend you receive the measles vaccine or protective antibodies (immunoglobulin or Ig) to prevent measles or make the symptoms less severe.

In a measles outbreak, the vaccine can be given to children as early as 6 months of age. However, 2 more doses of the vaccine must be given after the child is 12 months old to ensure long lasting immunity to measles.

Measles vaccination for adults

Adults born before 1970 may have had measles disease and may have natural immunity.

In Canada, the measles vaccine was introduced in the 1960s. It wasn't until the late 90s that a 2nd dose was introduced in the provinces and territories as routine childhood vaccination.

Since adults born in or after 1970 may have received only one dose of the measles vaccine in childhood, a second dose of the measles vaccine is recommended for adults who have never had measles. This is especially needed for:

  • travellers
  • military personnel
  • healthcare workers
  • students in post-secondary educational settings

Talk to your healthcare provider to make sure you've had all the vaccine doses recommended for you.

How measles spreads

Measles is caused by a highly contagious virus and it can spread very easily. The virus can live in your:

  • nose
  • mouth
  • eyes
  • skin

The measles virus spreads by:

  • breathing contaminated air where an infected person coughed or sneezed
  • touching a contaminated surface like door knobs, utensils, shopping carts and phones

If a person breathes the contaminated air or touches a contaminated surface, then touch their nose, eyes or mouth they can become infected. The measles virus can live up to two hours in the air or on surfaces in a space where a person coughed or sneezed.

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