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Hamilton Public Health Services strongly encourages parents to fully vaccinate their children against measles.

What to do if you think you've been exposed to measles chart

*You can check your immunization records with your healthcare provider or Hamilton Public Health Services by calling 905-540-5250.

Measles, also called rubeola, is a very contagious infection of the lungs (respiratory illness) caused by the measles virus. The measles virus normally grows in the back of the throat and lungs.

Measles is common in many parts of the world but is rare in countries that provide routine vaccines.  There are still some measles cases in Canada because travellers to and from other countries become infected and spread the virus to people who are not immune, usually people who have not been vaccinated.

Complications from measles can include pneumonia, ear infections, diarrhea, encephalitis (swelling of the brain) and blindness.  Complications are more common for children under five years of age and people 20 years of age or older.  Measles is a serious disease: one out of every 10 people who get measles develop complications, one out of every 1000 people who get measles die.

Measles is easily spread from person to person by:

  • A person with measles coughing or sneezing, spreading the virus into the air; and
  • Direct contact with nose and throat secretions (fluid), such as saliva from a person with measles

The measles virus can live in the air and on infected surfaces for up to two hours. If people breathe the contaminated air or touch the contaminated surfaces, then touch their eyes, nose, or mouths, they may become infected if they are not immune to measles.  Nine out of 10 unimmunized people who come in close contact with an infected person with measles will get the disease.  

A person with measles is contagious before showing symptoms.  A person with measles is very contagious from one day before the start of symptoms (usually about four days before the rash appears) until four days after the rash appears.

The following people are at risk of measles:

  • Anyone who has not had measles in the past or has not received two doses of measles-containing vaccine - either measles, mumps, rubella (MMR) or measles, mumps, rubella, varicella (MMRV)
  • Travellers and people who work in some jobs, such as health care workers or persons in the military, may be at higher risk for exposure to measles. Talk to you doctor, nurse practitioner or occupational health and safety specialist

People born before 1970 are generally considered to be immune as most people had measles before a vaccine was available. 

Risks of measles during pregnancy include:

  • For women who are not immune to measles, acquiring the illness during pregnancy increases the risk of premature labour, miscarriage and low birth weight infants.
  • Birth defects have not been linked to measles exposure.
  • Unimmunized women who are pregnant and have been exposed to measles can receive immunoglobulin within 6 days after exposure to prevent measles disease or reduce the severity of measles disease.
  • Pregnant women can receive the MMR vaccine after pregnancy to protect against measles in the future.

The current case in Hamilton most likely caught measles when travelling outside of Canada.

This case is not thought to be related to the current outbreak in Ontario. The current outbreak of measles in Ontario is usually seen in unvaccinated or under-vaccinated persons.

Previous outbreaks in Ontario have been directly or indirectly associated with travel outside of Canada.

Public Health Services interviews all persons diagnosed with measles. If you are identified as a contact, Public Health Services will do one or all of the following:

  • Call to inform you that you are a contact
  • If unable to reach you by phone, a letter is sent to your home
  • Issue a media release if the exposure may have happened in a public place such as a shopping mall or restaurant

If you think you have been exposed to measles, call Public Health Services at 905-546-2489 as soon as possible to speak with a Public Health Nurse who can assess your risk of developing measles. Monitor for signs and symptoms of measles for 21 days after the date you think you were exposed.

Symptoms of measles begin seven to 21 days after infection with the virus.


  • Fever of 38.3 C (101 F) or greater
  • Cough
  • Runny nose
  • Drowsiness (sleepy)
  • Irritability
  • Red watery eyes
  • Small white spots with white centres, known as Koplik’s spots, on the inside of the mouth and throat

Three to seven days after symptoms start, a red blotchy rash appears on the face and then spreads down the body. This body rash lasts from four to seven days.  Measles usually last for two weeks.

If you think you have symptoms of measles, stay at home.  Call your doctor if you think you or a family member has measles.  Make your appointment with your doctor at the end of the day so you do not expose other people at the doctor’s office to measles. You will receive a mask to wear when you get to your doctor's office and may be taken to a treatment room right away.

Your doctor may do a swab of your nose or throat, take a urine sample and order a blood test to show if you have measles now or have immunity to measles, either through previous immunization or having had measles in the past.   There are special time lines associated with each test. Your doctor will be able to explain this to you.

If you need to go to the hospital, a person immune to measles who is a friend or parent should go with you.  They need to tell the emergency room triage nurse that you may have measles and ask for a mask for you to wear. You should only go into the hospital once you have put on the mask.

There is no treatment for measles.  If you have measles, you need bed rest, fluids and medicine to help with your fever. Talk to your doctor about what you can do to make your symptoms manageable.  

If you have measles, you should:

  • Stay home.  Do not go to school, daycare or work for at least four days after your rash started.  You can leave the house on day five.
  • Clean your hands often with soap and warm water or use an alcohol based hand rub with 70 to 90% alcohol content.
  • Do not share drinking glasses or utensils with others.
  • Cough or sneeze into a tissue or your sleeve.

For specific questions about symptom management or medical care, talk to your doctor or nurse practitioner.

Here are some tips on how to prevent measles:

  • Measles is preventable by immunization with the free MMR vaccine (measles, mumps, rubella) or the free MMRV vaccine (measles, mumps, rubella, varicella).  If you have these vaccines you are considered immune to measles.
  • Children receive their first dose (as MMR vaccine) on or shortly after their first birthday, and their second dose (as MMRV vaccine) between four and six years of age. 
  • If your child had two doses of MMR vaccine at 12 and 18 months of age, they do not need another dose at four to six years of age, as long as your child received the first MMR vaccine on or after their first birthday, with at least 28 days between the first and second MMR.
  • Adults born in 1970 or later should receive two doses of MMR vaccine in their lifetime, given at least 28 days apart. 
  • Most adults born before 1970 are considered immune to measles, but some people may need to get a measles vaccine for work.  Talk to your Occupational Health and Safety specialist at work and your doctor. 
  • If you are unsure about the vaccines you or your child have received, ask your doctor.  If your doctor does not have the information, call Public Health Services at 905-540-5250.
  • After one dose of the vaccine, between 85 and 95% of people are immune to measles. After two doses, almost 100% are immune. 
  • The measles vaccine may make the symptoms of measles milder if you do get the virus.
  • Once someone has had measles, they develop immunity and are considered to be protected against measles for life.

  • German measles, also known as rubella is caused by a different virus.  People who have had German measles are not immune to measles (also known as red measles or rubeola).

People who should not receive the measles vaccine:

  • Pregnant women
  • Those with weakened immune systems due to disease or medications
  • Those who have had severe allergic reactions to previous doses of this vaccine or any of its components
  • Babies under 6 months of age

Talk with your doctor if for more information.  Women should delay pregnancy for at least 28 days after receiving a live vaccine such as MMR.  Breastfeeding women can still have the MMR vaccine.  

Read more about the MMR vaccine

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