Alberta has suspended its provincewide mumps inoculation campaign after five people suffered severe allergic reactions.

After receiving their mumps shots, five young adults were reported to have suffered anaphylaxis, a rapid swelling of the throat and airway which can lead to respiratory failure or brain damage. But they were treated immediately and have since recovered, health officials said Tuesday.

Alberta's mumps outbreak began on post-secondary school campuses, so the vaccination campaign targeted students and staff.
(CBC)

Three cases happened in the David Thompson Health Region in south-central Alberta and two were in the Capital Health Region, which includes Edmonton. All the patients had a history of allergic reactions.

Alberta is in the middle of a mumps outbreak that began in post-secondary schools in Lethbridge in October. Almost 160 cases have been confirmed in the province so far this year. The campaign, which began last month, has inoculated about 62,800 people between 17 and 26 years old.

Mumps is highly contagious and spread through saliva. It causes fever, swelling and pain in the parotid glands, located in front of the ears and below the cheekbones. In rare cases, it can lead to brain inflammation.

Alberta halted its mumps clinics pending an investigation by Health Canada. 

Almost 160 cases of the mumps have been confirmed in Alberta so far this year.
(CBC)

All five of the reactions came from one lot of vaccine, but two other lots were also produced from the same bulk products by pharmaceutical company Merck Frosst's plant in Pennsylvania.

The majority of the doses were delivered to Alberta, but B.C., New Brunswick, Ontario, P.E.I. and Quebec also received some of the vaccines. Those provinces have voluntarily suspended their mumps programs for the time being, said Alberta Health.

Health Canada said normal anaphylaxis reaction to a vaccine is one in a million.

"Obviously, our level of concern was great," Dr. Karen Grimsrud, Alberta's acting chief medical officer of health, said Tuesday afternoon.

Mumps shots continue for one-year-olds

Health officials said people who were administered the mumps shots are in no danger because severe reactions usually occur immediately after immunization.

People older than 26 and born in Canada should have a natural immunity to the mumps, while those under 17 should have already received two shots, which would fully immunize them from the virus, said Dr. Judy MacDonald, Calgary Health Region's deputy medical officer of health.

The shot, which protects against mumps, measles and rubella, will continue for one-year-olds in Alberta using unaffected supplies, but not for young adults and kindergarten students to conserve doses, said Grimsrud.

She said other provinces have been contacted to send extra doses until a new supplier can be found.