Measles stays quiet in Alberta but risk of flare-up remains, experts caution

Alberta's measles activity has gone quiet for weeks, but health experts are cautious about declaring the outbreak over.

No new measles cases have been reported since a single case in the first week of June. The Alberta government says there is currently no evidence of ongoing community transmission and the risk is considered low. Public health officials are updating measles guidance and advisories to reflect the improved situation.

"It's very encouraging," said Dr. Sam Wong, president of the section of pediatrics with the Alberta Medical Association.

But Alberta's outbreak has been severe. More than 2,300 Albertans have tested positive since outbreaks began nearly a year and a half ago. One death was reported last year.

Wong cautioned that some cases may still be circulating undetected. "If there are still cases occurring and they're not being reported or not being seen, then the outbreak may continue for a little bit longer," he said.

The province describes the current situation as "stable," but health officials warn that sporadic or travel-related cases are still possible as measles circulates in other jurisdictions. British Columbia reported five new measles cases between July 12 and July 18. The United States is battling multiple outbreaks and facing its worst measles year in decades.

Dawn Bowdish, an immunologist and professor in the department of medicine at McMaster University, urged continued caution. "Although levels are currently low, I don't think it's time for us to relax," she said. "It's such a contagious virus that without that incredibly high vaccination rate of well over 95 per cent there will be reintroductions."

Wong believes many unvaccinated Albertans were likely infected during the outbreaks. "Once it gets into a population that is not vaccinated it will go through that community fairly quickly," he said.