A national committee of health experts says that all Canadian children and susceptible teenagers and adults should receive two doses of mumps vaccine.

The recommendation from the National Advisory Committee on Immunization (NACI) comes as at least two provinces prepare to vaccinate returning university students in a bid to stamp out a lingering mumps outbreak.

People who have not received a second dose of the vaccine may experience diminishing levels of immunity, and may be susceptible to the virus.
(CBC)

The outbreak, which started in the Maritime provinces early this year, has resulted in at least 690 cases in nine provinces.

Canada's chief public health officer, Dr. David Butler-Jones, says that in light of the NACI recommendation, all students returning to school this fall should ensure they have had two doses of mumps vaccine.

Young children currently get two doses of the measles, mumps and rubella vaccines but those now in their late teens and young adults received only one dose when they were children.

According to the Public Health Agency of Canada (PHAC), it's believed most people over 40 have natural immunity to mumps through previous exposure to the virus.

But individuals who have not received a second dose of the vaccine may experience diminishing levels of immunity, and may be susceptible to the virus.

For this reason, PHAC feels that individuals between the ages of 12 and 40 years (or 17 and 40 years, depending on the jurisdiction) are considered to be among the most susceptible to mumps infection.

The August issue of the Canada Communicable Disease Report, published by the NACI, finds that the proportion of reported cases of mumps in Canadians aged 20 and older increased to 64 per cent between 2003 and 2005, from 14 per cent in 1988 to 1990.

At the same time, the proportion of cases in children aged one to nine fell from 49 per cent to 17 per cent.

Mumps can lead to infertility in men

Mumps is an infection of the salivary glands caused by a virus. The disease may involve fever and the swelling of the salivary glands located within the cheeks, near the jaw line below the ears, according to PHAC. Other symptoms may include headaches and muscle aches.

Mumps is spread though direct contact with respiratory droplets, saliva or contact with any surface that has been contaminated with the virus.

Most people recover from illness, but, in rare cases, mumps can be serious and there is no treatment. Individuals who become seriously ill may have encephalitis (infection of the brain), meningitis (a swelling of the covering of the brain), arthritis and deafness. One in three men may experience painful, swollen testicles.

Although very rare, some of these men may become infertile as a result of the infection.

With files from the Canadian Press