Whooping cough is on the rise in Canada

Whooping cough or pertussis, a very contagious respiratory infection caused by the bacterium Bordetella pertussis, is on the rise in Canada (1,2,3). 

The infection spreads easily through inhaling contaminated respiratory droplets (1). Once attached to the respiratory tract, the bacteria release toxins that damage cells and cause inflammation, leading to severe, uncontrollable cough with a characteristic “whoop” sound (1,3,4). Unlike the common cold, coughing can last for weeks to months (3).

In young infants, whooping cough can lead to serious complications like pneumonia, hernia, lung collapse, seizures, brain injury, and death. Teens and adults usually have milder symptoms, but they can still injure themselves from heavy coughing and spread the infection to more vulnerable individuals (1,5). 

Pertussis usually follows a cyclical pattern, with peaks of activity every 2 to 5 years. In Canada, the last peaks occurred in 2012, 2015 to 2017, and most recently in 2019 (1,6,7). Now, cases are rising again, with over 12,000 reported nationwide this year – far exceeding the usual 500 to 4,500 annual cases. Quebec has seen a particularly dramatic spike, with over 11,000 cases so far, well above its previous average of 562 per year. Ontario, with an average of 98 cases per year, had reported 470 cases by June, and New Brunswick just declared an outbreak (2,8).

Vaccination is the best defense, protecting against severe illness and helping to limit the spread of whooping cough. The pertussis vaccine is part of routine immunization: children are recommended to receive a dose at 2, 4, 6 months, and between 12-23 months (generally given at 18 months of age), with boosters between 4-6 years and again 10 years later (i.e. between 14 and 16 years old). Vaccination during pregnancy is also recommended, providing protection to newborns until they can receive their first dose (9).