Whooping cough outbreaks persist in Alberta as health officials urge vaccination

As pertussis cases continue to climb, Albertans are being warned to ensure their children are up-to-date on their immunizations.

The highly contagious bacterial infection, commonly known as "whooping cough," can impact people of all ages, but babies are at the highest risk.

Between Jan.1 and Feb. 21 of this year, 78 cases were identified.

There were 884 lab-confirmed cases in Alberta in 2023, making it the second worst year for whooping cough in the past decade.

The latest surge began when cases started appearing in southern Alberta last year. An outbreak was officially declared in the south zone in January 2023. Whooping cough eventually spread around the province.

Data provided by Alberta Health Services (AHS) shows 966 cases were reported between November 2022 and Feb. 21, 2024. Here is a breakdown by zone:

• South zone — 452.

• Central zone — 68.

• Calgary zone — 42.

• Edmonton zone — 39.

• North zone — 365.

According to AHS, there were 29 hospitalizations during this time period. No deaths were reported.

In a recent public service announcement, AHS cautioned that case are rising.

"Routine immunizations are more important than ever. Cases of pertussis have increased in Alberta in the last few months and have been identified in all AHS zones," the statement said, noting infants are at the greatest risk of complications.

The most recent outbreak was declared Feb. 2 in the Edmonton zone, where there have been four cases, according to AHS.

Dr. Jia Hu is a Calgary-based public health physician and adjunct professor at the University of Calgary. He says it's important that people stay up-to-date with their recommended routine vaccinations. (Erin Collins/CBC)

"I think it speaks to a broader decline in vaccine uptake leading to the re-emergence of different vaccine-preventable diseases," said Dr. Jia Hu, a Calgary-based public health physician who teaches at the University of Calgary.

This comes at a time when measles outbreaks are sparking concerns globally and travel-related cases are being identified in Canada.

Pertussis is often called the 100-day cough because the distinctive cough that comes along with it can last for months

According to AHS, it starts with a runny nose, sneezing, fever and mild cough.

The cough eventually becomes more severe and, in younger children, coughing fits are often followed by a "whooping" sound as they inhale. These spells can be punctuated by vommitting.

Pertussis can lead to pneumonia and, in rare cases, it can result in brain injury, seizures or even death.

Vaccine recommendations

Alberta's routine childhood immunization schedule recommends babies receive their first dose of the vaccine that protects against pertussis (dTAP) at two months of age, with further doses at four, six and 18 months.

Boosters are also supposed to be given when children are four years old and again in Grade 9.

The percentage of Alberta children up-to-date with the pertussis vaccine by age 2 dropped to 71 per cent in 2022, down from 78 per cent in 2008. In the north and south zones, rates have dropped below 60 per cent, with some areas reporting much lower vaccination rates.

"Usually there's a big drop off for that fourth dose, and so I think it's really important that people stay up-to-date with their recommended routine vaccinations," said Hu.

Provincial data shows 91 per cent of two-year-olds have one dose of the vaccine, compared with the 71 per cent who have all four doses.

"We're most worried about pertussis in very young kids — you know, less than one year of age, sometimes less than that — because they have less immunity to pertussis and are more likely to be hospitalized for it," said Hu.

According to the AHS website, whooping cough causes between one and four deaths in Canada each year.

"These deaths are most often in babies who are too young to be immunized or children who are not fully immunized," it states.

Pregnant Albertans should also be immunized against pertussis, according to Hu, because they pass along antibodies that help protect their newborns when they're too young to be immunized.

The National Advisory Committee on Immunization recommends the shot be offered during each pregnancy, ideally between 27 and 32 weeks gestation.

In addition, the province recommends all adults get boosted every 10 years.

Pertussis can be treated with antibiotics.

AHS said people who test positive for pertussis should stay home until five days of antibiotic treatment have been completed. Alternatively, people should stay home until three weeks after their cough starts or until the cough ends, whichever comes first.