Experts at the BC Centre for Disease Control (BCCDC) are already gearing up to monitor flu-like illness for the coming season and they're looking for more community doctors and nurses to help.
Influenza viruses constantly change, and each season the flu shot has to be updated to match the new strains that are most likely to make people sick. Last year, influenza got off to an early start and the 2014-15 flu season proved to be a difficult one, in part because of the vaccine mismatch. In BC, that translated into the highest number of care facility outbreaks in more than a decade.
"A changed strain of H3N2 virus that didn't match the vaccine caused most of the influenza illness last winter," says Dr. Danuta Skowronski, an influenza expert at BCCDC. "H3N2 viruses tend to cause more illness, especially in older people, which is why it is so important to monitor this virus closely every year."
In 2004, Dr. Skowronski's team pioneered a study, known as the "test-negative design" for monitoring influenza vaccine effectiveness, a cost-effective approach that is used each year in Canada and has since been adopted by approximately 20 countries around the world. Yearly findings based on the test-negative design are submitted to the World Health Organization (WHO) to help decide whether changes to the influenza vaccine are needed.
"Last year showed the lowest vaccine effectiveness we have recorded in more than ten years," says Dr. Skowronski. "The WHO has replaced last year's H3N2 vaccine with a new one and we want to check that it gives better protection for the coming season. We rely on doctors and nurses in the community who belong to our monitoring network to help with that."
The Canadian Sentinel Practitioner Surveillance Network (SPSN) is the only system in Canada to monitor how well the influenza vaccine protects people from influenza viruses circulating in the community each year. The SPSN uses the test-negative design, drawing on swabs and information collected from patients seeking care for flu-like illness at one of several hundred community practitioners belonging to the network.
"The SPSN has grown to include sites in Alberta, Ontario and Quebec but we need more family doctors and nurses to contribute from BC," says Skowronski, the lead SPSN investigator. "After last year's findings, monitoring flu viruses and vaccine protection is more important than ever."
Throughout September, the BCCDC team will be packaging and sending out hundreds of special swab kits to existing sentinel sites in BC, but the team is also recruiting more family doctors and nurses to join the network for the coming season. Family practitioners in BC who would like to join are asked to contact the BCCDC team at SentinelNetwork@bccdc.ca or 1-888-881-8886. Patients can also encourage their own family doctors to join by sharing information about the network with them.
General practitioners in Alberta, Ontario and Quebec are also encouraged to apply to join the Canadian SPSN network for flu virus and vaccine effectiveness monitoring. See www.bccdc.ca/SentinelNetwork for details.