Measles and the International Traveller
Measles is a highly contagious disease spread by a virus easily transmitted through the air. It was once a common disease in Canada during childhood. Before the introduction of the measles vaccine the disease caused an estimated 2.6 million deaths worldwide, and was a significant cause of disability.
Measles is still common in many developing countries, especially in Africa and Asia. Outbreaks continue to occur worldwide. Current outbreaks include Mauritius, Mali, Uganda, Russia, Spain, New Zealand, Colombia, Czech Republic, Taiwan, Japan, Belarus, Liberia, Kosovo, Syria, Italy, Brazil, Ireland, Philippines, United Kingdom, and France to name a few. You don’t need to be traveling to a developing country to be at risk for measles!
Symptoms of measles begin 7-21 days after being exposed and can include high fever, rash, cold-like symptoms and red, inflamed eyes. Complications of measles can include diarrhea, ear infection, pneumonia, and encephalitis (swelling of the brain that can lead to seizures, deafness, or permanent brain damage). There is no cure for measles; treatment is only supportive. About 1 in 3000 people with measles will die from complications.
The efforts toward the elimination of measles in Canada
A single dose of the measles vaccine has been recommended in Canada for infants at 12 months of age since 1970. Between 1996-1998 a 2-dose vaccine program was implemented, and a second dose was then given to children and adolescents previously vaccinated under the 1-dose program. Receiving two doses of the measles vaccine is more than 99% effective to protect against measles, compared to 93% after one dose. However, some people missed out on this second dose of measles vaccine and as a result could still be susceptible to measles. In BC children currently receive their first dose of the measles, mumps, rubella (MMR) vaccine at 12 months of age, and a second dose between 4-6 years of age.
In 1992 Canada set a goal to eliminate measles by 2005. Although elimination usually implies a total absence of cases, this is not possible as importations can still occur from countries with less control over measles. Elimination of measles in Canada was therefore defined as the interruption of endemic measles transmission for at least 1 year, and failure to reestablish endemic transmission after importation (endemic refers to a disease that is regularly found among a particular population or certain area). The goal of measles elimination was achieved in Canada in 1998.
Despite Canada’s efforts to maintain elimination, there continues to be outbreaks of measles throughout the country. The 2011 outbreak of 725 reported cases in Quebec was the highest number of cases since 1995. There was also a large outbreak in 2014 in B.C.’s Fraser Valley with 433 reported cases. There have also been other outbreaks in various regions in Canada.
So why are there still measles outbreaks after it was eliminated in 1998?
There continues to be measles outbreaks in Canada mainly due to cases imported from international travellers who acquire the disease abroad which can then be spread to unvaccinated or partially vaccinated individuals. In recent years Canada has experienced falling vaccination rates due to a number of reasons including anti-vaccine views and incompletely immunized individuals. The vaccine coverage rate in Canada is close to 90% but it needs 93-95% to protect the population against measles.
International travel and the MMR vaccine
The measles vaccine is available only in combination with mumps and rubella (MMR vaccine). The best way to prevent the spread of measles and importing it to Canada is to ensure you are properly immunized before international travel, even to industrialized countries. Travellers should receive the vaccine according to the following guidelines:
- Infants between the ages of 6-11 months should receive 1 dose of MMR. Infants who received the vaccine before 12 months of age must be revaccinated according to the routine schedule (dose #1 at 12 months of age; dose #2 at 4-6 years of age).
- Children 12 months of age and older should receive 2 doses of MMR separated by at least 28 days.
- Adults born after 1970 (1957 for health care workers) should receive 2 doses of MMR separated by at least 28 days (individuals born prior to 1957 are assumed immune to measles from natural infection). Those born between 1957 and 1970 are generally assumed to have acquired immunity from natural infection, however those without documentation of 2 doses of measles vaccine, or those who do not self-identify as having had the disease may be susceptible and should receive 1 dose of MMR.
Common reactions to the MMR vaccine include redness, tenderness and swelling at the injection site. A mild fever, rash, or swelling of the glands in the cheeks or neck can occur about 7-12 days after receiving the vaccine. Temporary joint pain may also occur in teenage and adult women.
A published report linking the MMR vaccine to autism has never been replicated by any other study. The report has been widely discredited and has been retracted by the journal.
There are some people who should not get the MMR vaccine including individuals who:
- Have had a severe allergic reaction to a previous dose of the MMR vaccine or any vaccine component
- Are severely immunosupressed
- Are pregnant or planning pregnancy (women should avoid pregnancy for 1 month after receiving the MMR vaccine)
- Have had a blood transfusion or received other blood products in the last 12 months
- Have had a drop in platelets after a previous dose of MMR
There is no need to delay the MMR vaccine if you have a cold or another mild illness.
Getting ready to travel?
There is an estimated 20 million people infected globally each year with measles, so travellers may be exposed to the virus in almost any country they visit. As an international traveler it is important to ensure your MMR vaccines are up to date. Protect yourself against measles and ensure you do not become an importer of the disease!