Interior Health is warning individuals and families to be vigilant against pertussis, commonly known as whooping cough, as cases of the highly contagious respiratory infection increase across the region.
Health officials say infections have risen in recent weeks and are expected to climb further through the summer as travel, camps and large gatherings create more opportunities for the disease to spread.
“Public health officials are asking everyone to stay informed and help prevent the spread,” Interior Health said in a June 5 public advisory.
Pertussis spreads through coughing and sneezing and can be transmitted before infected people realize they are sick.
The illness often begins with symptoms similar to a common cold, including a runny nose, sneezing, mild fever and a mild cough.
After one to two weeks, the cough can become severe and persist for several weeks.
Some people experience intense coughing fits that can make breathing difficult and may lead to vomiting.
The disease poses the greatest risk to infants under the age of one, who can develop serious complications requiring hospitalization. Interior Health said most babies who contracted pertussis in 2025 required hospital care.
Health officials say most cases occur among children and youth who are not fully immunized.
The agency is encouraging residents to ensure their vaccinations are current, noting immunization remains the most effective protection against severe illness and transmission.
Pertussis vaccines are available free of charge in British Columbia as part of the routine childhood immunization schedule.
Health officials are also urging pregnant women to receive the vaccine during pregnancy because it helps protect newborns before they are old enough to receive their own immunizations.
Anyone can contract pertussis, but those considered most vulnerable include infants, people who are not fully immunized, pregnant women in their third trimester and people who live or work with vulnerable populations.
Protection from vaccination or a previous infection can diminish over time, meaning older children and adults can still become infected and spread the disease.
People who develop a worsening cough or one that lasts longer than a week are advised to contact a health-care provider.
Those who suspect they may have pertussis should call ahead before visiting a clinic or hospital, stay home and avoid close contact with others, particularly babies and pregnant women.
Antibiotics can reduce the length of time an infected person remains contagious, although untreated individuals may spread the disease for several weeks.
Interior Health said residents can contact their local health centre or call HealthLink BC at 8-1-1 for information about testing, treatment and immunization.