BURST
The public health storm of a quarter-century is brewing in Alberta, with 118 confirmed cases of the highly-infectious measles virus, according to Alberta Health Services — an uptick of 29 cases provincewide since before the Easter long weekend.
An individual who was served at three Edmonton-area clinics on an unrelated medical matter was highly infectious with measles in recent days, sparking a public alert from Alberta Health Services about potential exposures.
Anyone who was at these locations needs to check their immunization records and watch for symptoms.
April 10 – Kinder Care Medical Clinic, 11125 107 Ave. NW, Edmonton. Exposure period: 1:45 p.m.–4:38 p.m.; April 11 – Ross Creek Medical Imaging, 10101 86 Ave., Fort Saskatchewan, Exposure period: 7:50 a.m.–11 p.m.; April 14 – ROKband Pediatric Headshape Clinic, 9945 50 St. NW, Edmonton, Exposure period: 9 a.m.–12 p.m.
In Taber, confirmed cases of measles have been in public areas while infectious, AHS said in a statement released Monday.
Anyone who attended these locations at these times, who was born in or after 1970 and has fewer than two documented doses of measles-containing vaccine, is at risk of developing measles. These individuals should self-monitor themselves of symptoms of measles and are strongly encouraged to review their immunization records.
Worst in more than 25 years
Canada is having the worst measles outbreak in a quarter-century, said Dr. Lynora Saxinger, an infectious diseases specialist at the University of Alberta, noting that Ontario alone has more than 900 cases.
“The last big measles year in Canada was 2011, with 752 cases in the entire year, and we’ve far surpassed that. And it’s only April,” she said.
Most years, there are fewer than 50 cases a year. In 2014, there were 418 cases all year.
“We’re just heading right back to the 1800s,” she said.
Infants in the six- to 12-month age may be particularly vulnerable to the measles virus because any natural immunity they may have gotten from their mother has waned, but they’re too young for being scheduled for their first long-term measles-mumps-rubella dose, and will need to be protected by herd immunity, which occurs around the 96 per cent mark, Saxinger said.
“Clinics full of infants having an exposure — I’m sure those parents must be very concerned,” Saxinger said.
Among young adults in Alberta, herd immunity has dipped below the needed 96 per cent but, among small children, the rate has dropped down into the 60-70 per cent range, and much lower in some isolated communities.
“Yeah, that’s not enough. It’s kind of alarming,” Saxinger said.
Some younger children may have had their vaccination schedules scrambled by the pandemic and public health getting backed up and distracted, Saxinger said.
“But there’s also been increasing vaccine distrust that kind of flared up during the pandemic and with social media. So there likely is also a cohort that’s more likely to have significant vaccine concerns in spite of the good evidence that it’s safe and useful,” she said.
“It’s kind of unclear what’s going to happen in terms of the direction right now, it depends on how many susceptible people we’re sharing space and airspace with the infectious individuals that have been detected so far,” Saxinger said.
“If they happen to be in spaces where you know most of the people have done the usual thing and are fully vaccinated, it doesn’t necessarily take off and keep going that far. If you end up having introduction of measles into a very susceptible population with low vaccine rates, it gets a lot more complicated, and it can kind of keep going for a while, especially because it takes a while to actually detect the cases because of the long incubation period.
“It might actually go on for a while, and the more measles that’s around, the more likely it is that we will see the occasional breakthrough case in someone who has been immunized, just because the immunization is excellent, but not perfect. The more exposures, the more likely we’ll have occasional cases in people who have had full immunization, and a little more commonly in people who’ve had only one dose,” she said.
‘No picnic for adults’
Complications like ear infections, pneumonia and encephalitis can occur across age ranges, but tend to concentrate in the younger kids, Saxinger said.
“It’s really no picnic for adults to get measles either, and quite frequently, people end up needing hospital admission for supportive care, and they can have lung and liver complications as adults,” she said.
The mortality rate is one in 1,000 and one in 1,000 get encephalitis, but b acterial infections are more common because measles can suppress an immune response.
“There’s quite a high burden of infections after measles,” Saxinger said.
More than half the deaths from measles are from pneumonia.
“Classically and worldwide, measles mortality is highest in kids under five, especially under one. It is a disease that can be deadly,” she said.
“It’s still pretty standard that you will start seeing some deaths and some severe complications, and that we don’t always count all the complications on the public health side.”
The vaccination for measles is typically bundled with vaccinations for mumps and rubella, and often with chicken pox vaccine as well.
“As a package, that’s a pretty good chunk of major childhood illnesses prevented with one vaccine,” said Saxinger.
“It’s kind of hard to argue against it, and to be honest, the other components of MMR are also things that are starting to come up more commonly in a lot of different places because of the overall dropping of rates. Measles is kind of the thin edge of the wedge. Because measles is so very contagious, you need a very high proportion of immune people to prevent it from taking off,” she said.
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