The Canadian Medical Association Journal published a study this week comparing blood levels of antibodies against the H1N1 influenza virus before and after the 2009 pandemic. The research looked at 1,127 people in British Canada’s Lower Mainland, aged between 9 months and 101 years.
Results indicated that prior to the pandemic less than 10% of children and adults under 70 had protective levels of antibodies, whereas 77% of those over 80 did have antibody protection. Dr. Danuta Skowronski of the B. C. Centre for Disease Control believes that this may be because of early exposure to a similar infection in childhood, which the immune system ‘remembers’.
Follow-up testing showed antibodies in 70% of those under 20, in 44% of those between 20 and 49, and in 30% of those aged 50-79. However, people aged 70-79 had the lowest rate of antibodies (21%), while those over 80 had the highest rates.
These findings could be explained by the prioritised vaccination of children, since they were the most at-risk during the pandemic. The findings ultimately suggest that older Canadians—aged 50 and above—should get a flu vaccination to avoid getting sick.