A recent study from the London School of Hygiene has found that winter infections such as influenza can double the risk of heart attacks and strokes. The effects were found to be independent of age or gender. Victims are twice as likely to be affected during the week following a respiratory infection. The extensive study included two million patients.. Scientists believe that infections such as the flu dislodge fatty deposits and/or blood clots that accumulate in the arteries, leaving them free to move around the body and potentially clog the circulation of the brain or heart where they may block blood flow. There are also cases where viral infection causes short-term abnormalities in blood clotting, with thrombosis and embolism occurring in both sexes and all ages immediately following infection. This research has prompted calls from experts to encourage all who have cardiovascular diseases to have an annual flu shot to minimize their risk.
The study revealed that 23,000 more people die of heart attack and stroke in winter than in summer. Of these, 11,000 suffered a heart attack and were twice as likely to have had a respiratory infection in the previous month.
Additionally, the 9,000 who had a stroke were twice as likely to be diagnosed with a respiratory infection during the prior three days. The researchers say that the post-flu risk of suffering from a heart attack or stroke declined over time, and after three months there was only a slightly increased risk.
Co author of the study, Professor Tom Meade, says that heart attacks and strokes brought on by the flu could account for several thousand of winter deaths, and vaccinating against respiratory complaints could have a significant effect on lowering the number of victims.