Whooping cough is making a surge in Canada at a time when schools are reopening and ahead of the fall respiratory illness season.
Some provinces — Ontario, Quebec and New Brunswick in particular — have reported sharp increases in whooping cough cases compared with pre-pandemic averages.
Whooping cough, which is a bacterial illness, “can be seasonal” as it peaks in late summer and early fall, said Dr. Anna Banerji, a pediatric infectious diseases specialist in Toronto.
With kids returning to school, experts warn that cases could rise even higher.
“I think that now that kids are going back to school and some of the kids are not completely vaccinated, I expect to see an increase,” Banerji said in an interview with Global News on Tuesday.
“We’ve already had huge numbers, four times the normal rate of whooping cough that we normally see across Canada and really around the world, but I think that might even go up as kids go back to school.”
Dr. Earl Rubin, a pediatric infectious disease specialist in Montreal, said schools can play a role in whooping cough spread and “certainly increase the risks of transmission.”
Like respiratory viruses, such as influenza, respiratory syncytial virus (RSV) and COVID-19, bacterial infections, like whooping cough, are more common during the fall and winter months, said Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital.
So, how can you tell the difference?
What is whooping cough?
Whooping cough, also known as pertussis, is a highly contagious respiratory infection.
The bacteria that cause whooping cough spread easily from person to person through the air, according to the U.S. Centers for Disease Control and Prevention (CDC).
When a person who has whooping cough sneezes or coughs, they can release small particles with the bacteria in them, and other people can then breathe in the bacteria, the CDC states on its website.
A distance of about one metre is enough to get exposed, Banerji said.
Bogoch said while whooping cough infection can be more pronounced and severe in the youngest population, it can affect people of all ages.
“It’s important to recognize that whooping cough can affect anybody of any age,” he said.
What are the symptoms?
Whooping cough symptoms can typically start appearing within a week to 10 days after exposure to the bacteria, but sometimes it can also take as long as four weeks, according to the Public Health Agency of Canada (PHAC).
The early symptoms of whooping cough make it appear as if it’s a common cold, with a low-grade fever, runny or stuffed-up nose, red watery eyes and a mild, occasional cough.
“The initial week or so would be indistinguishable from other upper respiratory tract infections,” Bogoch said.
“But the hallmark feature of whooping cough is a prolonged cough and a severe cough,” he said.
The illness can evolve over several weeks to include coughing fits that often end with a high-pitched “whoop” sound when an infected person is catching their breath.
The coughing fits may cause difficulty breathing, choking and vomiting, PHAC says.
The coughing spells can also make people feel very tired, have difficulty sleeping at night or fracture a rib, according to the CDC.
Banerji said since it’s a “very violent cough,” people can also turn blue or blood vessels can rupture in their eyes.
Coughing fits can last one to 10 weeks. This is why this illness is typically called the “100-day cough,” Bogoch said.
Babies and young children are at greatest risk, as their symptoms can be more severe and they could develop serious complications, such weight loss, apnea, pneumonia, convulsions and brain damage. There is also a risk of death for the youngest cohort.
Teenagers and adults can get pneumonia as well from whooping cough, but complications are usually less serious in the older age groups, the CDC says.
A nasal test can confirm if a person has whooping cough or not.
How to protect yourself
The best way to prevent whooping cough infection is through vaccination, experts say.
Vaccines that protect children against whooping cough are part of Canada’s routine immunization program, beginning at two months old. Primary immunization requires four doses, followed by booster shots later in childhood and adolescence.
A dose of acellular pertussis-containing vaccine is also recommended for adults and during pregnancy.
Vaccinated people can still get sick with whooping cough, but the illness is “generally milder,” according to the CDC.
Banerji said the pertussis vaccine is “very effective,” but the immunity can wane over decades, so parents should make sure children going back to school are up to date on their vaccinations.
If a child is sick, they should stay home until treated to reduce the infectiousness, she said.
Antibiotics can help treat whooping cough and should be given early in the illness to reduce the severity and maybe even avoid the coughing spells, Banerji said.
Once the whooping cough phase is established, taking fluids and rest can manage the symptoms, she added.
— with files from Global News’ Sean Previl and The Canadian Press.