Lack of herd immunity could cause mumps to spread, says province

The number of Manitobans vaccinated for mumps is low enough that there is a risk of the illness spreading, says Manitoba Health.

Number of mumps cases in Manitoba double compared to typical years

Manitoba Health says herd immunity for mumps in the province is only about 60 per cent and there is a risk of the illness spreading. (Jae C. Hong/ AP)

The number of Manitobans vaccinated for mumps is low enough that there is a risk of the illness spreading, says Manitoba Health.

Only 70 per cent of people in the province are vaccinated for mumps, a shot that is normally administered with vaccines for measles and rubella. Because the vaccine is 85 per cent effective, herd immunity stands at about 60 per cent, said a spokesperson for Manitoba Health.

Nine cases of mumps have been reported in Manitoba since the start of September, doubling the usual number in a year.

Seven of those cases involve individuals from the University of Manitoba who live in Winnipeg and were not hospitalized, public health officials said Thursday.

Herd immunity occurs when most people in a community receive a vaccine for a particular disease therefore protecting people who are unable to be vaccinated due to health conditions or age, says Health Canada.

With only 60 per cent herd immunity in the province, the spokesperson for the province says, "there is a risk for this virus to continue to spread."

"What is important is ensuring that as many people as possible are fully vaccinated, thereby increasing the overall herd immunity, will have the greatest impact on controlling the spread of this virus."

Higher than normal numbers

"Normally we have four to five in a year, so having a few, we don't always get worried about.… It's also essentially within a defined population," said Dr. Richard Rusk, the province's medical officer of health for communicable diseases.

University of Manitoba spokesperson John Danakas said there's been at least four confirmed cases on campus and the affected people "have been isolated."

"This means they have been asked to stay at home," he said.

Although there can be rare complications from mumps, the vast majority of cases are mild, with full recovery in one to two weeks, health officials say. (iStock)

Two of those confirmed to be sick are players with the Bisons football team. Those players won't be travelling with the team to games this weekend, Danakas said.

Winnipeg Regional Health Authority public health officials are investigating each mumps case and identifying people who came into contact with the affected individuals, a Manitoba Health news release says.

"Where appropriate, people will be offered immunization," the release states.

"Individuals with mumps will be asked to restrict their contact with others to reduce the possible spread of mumps. Public health officials will continue to monitor the situation in Manitoba and will provide updated information as necessary."

Although there can be rare complications from mumps, including fertility problems in men, the vast majority of cases are mild, with full recovery in one to two weeks, health officials say.

Key symptoms include swelling and pain in one or more salivary glands, usually on both sides of the face, as well as a fever. Headaches and muscle aches are also usually associated with the virus.

Rusk said as far as he knows, four of the seven people at the university who have the mumps were immunized. It's not too late for people on campus to get the mumps vaccine, he added.

The university's medical clinic is being used to test students with symptoms. Rusk said he expects the number of mumps cases to rise over the next few days.

The neck of a young child shows the characteristic swelling of mumps, due to enlargement of the salivary glands. (Manitoba Health)

Every person with mumps can spread it to about five other people, he said.

"This can definitely spread, so we are concerned," he said.

"But we also know that by improving our overall vaccination rates in that population, as well as ensuring that people follow typical isolation approaches, we can get this contained."

FYI on mumps

  • The mumps virus can be passed on to others when an infected person passes fluids from the mouth and nose to another by sharing drinks, food or cigarettes, by kissing or by coughing or sneezing within a few feet of another person.
  • The mumps virus can be spread to others from two to three days before and four to five days after symptoms appear.
  • Some people infected with mumps may not have any symptoms but can still spread the virus to other people.
  • After exposure, it can take 25 days before a person develops symptoms.
  • A person who develops symptoms or signs of mumps should limit contact with others for five days and contact their health provider.

In Manitoba, a two-dose measles/mumps/rubella (MMR) vaccine program was introduced in 1996. Protection against mumps is offered free of charge as part of Manitoba's routine immunization schedule at 12 months of age and again at four to six years of age.

Manitobans are urged to contact their health-care providers to determine whether they require the vaccine.

People who think they might have mumps or who have been in close contact with someone who has been diagnosed with mumps should phone their health-care providers or phone Health Links-Info Santé at 204-788-8200 or 1-888-315-9257 (toll-free) for more information.

If visiting a physician or health-care provider, it is best to call ahead and make an appointment so health-care staff can take steps to reduce exposure of other people to the virus.

To reduce the spread of mumps, people should:

  • Wash their hands often with soap and water or use hand sanitizer if soap and water are not available.
  • Avoid sharing drinking glasses or eating utensils.
  • Cover coughs and sneezes with the forearm or a tissue.
  • Stay home when sick.

Manitoba Health says it currently has MMR vaccines in stock and eligible Manitobans can contact their healthcare providers if they need to be vaccinated.

More information about mumps can be found on the Manitoba Health website.