The 2018/19 influenza vaccine is 72 per cent effective against the H1N1 kind of influenza A virus that is dominating this year’s flu season in Canada. The vaccine is offering much better protection than recent years, according to the mid-season analysis performed by the Canadian Sentinel Practitioner Surveillance Network (SPSN).
The SPSN is a network headquartered at the BC Centre for Disease Control (BCCDC) that measures how well the influenza vaccine works every year. Those estimates are based on specimens and data submitted by hundreds of general practitioners from patients presenting with flu-like illness. The network operates in the four largest provinces of Canada: Alberta, British Columbia, Ontario and Quebec.
“A vaccine effectiveness of about 70 per cent means for every 10 cases of influenza in unvaccinated people, the number would have been reduced to just three cases if they had been vaccinated,” said Dr. Danuta Skowronksi, lead for the Influenza and Emerging Respiratory Pathogens Team at the BCCDC and the lead of the Canadian SPSN. “That’s an important reduction in risk, especially for people with underlying medical conditions who face a greater threat of serious complications if infected by influenza.”
The H1N1 virus tends to have a greater effect on children and non-elderly adults, whereas the H3N2 virus tends to be harder on the elderly. The vaccine affords protection against both H3N2 and H1N1 influenza A viruses, as well as influenza B, which may make an appearance later in the season.
“Vaccine effectiveness in general tends to be better against H1N1 viruses than the other kind of influenza A, called H3N2,” said Dr. Skowronski. “This year’s vaccine performed well in part because the H1N1 kind of influenza A virus has been dominating and because this year’s vaccine is a good match to that circulating virus.”
The vaccine effectiveness results were published online today in the journal Eurosurveillance
In addition to vaccination, there are other steps people can take to reduce their own risk and minimize the spread of viruses to others. This includes:
- Wash your hands frequently especially if you’ve been out in public.
- Avoid touching your face, especially your eyes, mouth and nose.
- Cough and sneeze into your elbow. If you use a tissue, make sure to dispose of it properly and wash your hands.
- If you feel unwell, stay home so you don’t pass your infection onto others, especially those who may be at higher risk.
- If you are in close contact with people at higher risk of serious complications from influenza, get the vaccine and don’t visit them if you feel unwell.
The latest influenza surveillance reports for B.C. are available here