Study finds whooping cough vaccine provides little long-term protection

Watch above: Whooping cough has been making a comeback right across North America. Lower immunization may have been a factor, but the vaccine may also be to blame. Heather Yourex reports.

CALGARY – A new study published in the medical journal Pediatrics has found the Tdap vaccine provides little long-term protection against whooping cough.

The U.S. Centers for Disease Control study analyzed a recent whooping cough outbreak in Washington state. Four hundred and fifty teens were tracked one, two and four years after receiving the vaccine. Researchers found immunity after one year averaged 73 per cent, but dropped to 34 per cent after two to four years.

Since January 2014, there have been 513 cases of whooping cough in Alberta.

Alberta Health Services says there were outbreaks declared in 2014 in both the central and south zone.

READ MORE: Whooping cough outbreak declared in Southern Alberta

Officials believe low immunization rates contribute to the spread of the disease, but are also concerned the vaccine may not provide adequate protection.

“We’re seeing some waning of immunity from some of the people that have been vaccinated previously and that is something that we watch carefully,” said Dr. Judy MacDonald, AHS medical officer of health for the Calgary Zone.

Alberta Health recommends five doses of Tdap vaccine for all children before they enter pre-school, a sixth dose is recommended for adolescence in Grade 9.

“Vaccine effectiveness may not be as good as we would like, but without vaccine at all, disease is the alternative,” said MacDonald.

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Whooping cough is a bacterial infection that can cause illness for people at any age, but small children and infants are at the greatest risk of serious complications. In 2012, whooping cough claimed the life of a baby girl from southern Alberta.

“The symptoms of whooping cough start off as a regular cold and then progress to what we call a paroxysmal cough,” said Dr. Jim Kellner, head of pediatrics at the Alberta Children’s Hospital. “A paroxysmal cough is where you have episodes of coughing and then you take a deep breath in, and that’s the whoop.”

Kellner recommends adults, especially those who act as a caregiver to an infant, receive a booster shot of the Tdap vaccine.

Alberta researchers are also studying whether giving a dose of the vaccine to pregnant women during their third trimester can offer protection to babies during the first few months of life.