This season’s influenza vaccine is estimated to have been more than 40 per cent effective in preventing illness with the dominant H3N2 viral strain in Canadians who got their shots, a national network of infectious diseases experts says. The Canadian Sentinel Practitioner Surveillance Network determines vaccine effectiveness by analyzing how many inoculated people tested positive for the flu virus compared to those who were unvaccinated.

This season’s influenza vaccine is estimated to have been more than 40 per cent effective in preventing illness with the dominant H3N2 viral strain in Canadians who got their shots, a national network of infectious diseases experts says. The Canadian Sentinel Practitioner Surveillance Network determines vaccine effectiveness by analyzing how many inoculated people tested positive for the flu virus compared to those who were unvaccinated.