Colds, flu may temporarily increase stroke risk in kids

Stroke is very rare in children, but colds, flu and other minor infections may temporarily increase stroke risk in children, according to a study published in the September 30, 2015, online issue of Neurology, the medical journal of the American Academy of Neurology. The study also found routine childhood vaccines may decrease the risk of stroke.

"Parents should be reassured that while the risk was increased, the overall risk of stroke among children is still extremely low," said José Biller, MD, with the Loyola University Chicago Stritch School of Medicine in Chicago, author of a corresponding editorial and a Fellow with the American Academy of Neurology. "It is possible that changes in the body as a result of these infections, such as inflammation and dehydration could tip the balance in a child who is already at a higher risk for stroke. Parents should not be alarmed if their child has a cold that it will lead to a stroke."

For the study, researchers reviewed the medical charts and conducted parent interviews of 355 children under 18 diagnosed with a stroke and 354 stroke-free children of similar ages. Scientists looked at whether the children had been exposed to infection and also their vaccine history.

Of the participants, 18 percent of the children with stroke had an infection the week before the stroke occurred and 3 percent of the children who did not have a stroke had an infection the week before the interview with researchers. The children with a stroke were six times more likely to have an infection in the previous week than those who did not have a stroke.

The researchers found that the risk of stroke was increased only for infections in the prior week, indicating that the effect of infection on stroke risk is short-lived. Infections that occurred a month or six months prior were not associated with an increased risk.

Children who were poorly vaccinated were at a higher risk of stroke than those who had most or all of their routine vaccinations. Children who had received some, few, or none of their routine vaccinations were seven times more likely to have a stroke than those who received most or all of their vaccines. Eight percent of the children with strokes were poorly vaccinated, compared to 1 percent of those who did not have strokes.

"If our results hold up in further studies, controlling infections like colds and flu through hand-washing and vaccines may be a strategy for preventing stroke in children," said study author Heather J. Fullerton, MD, MAS, with UCSF Benioff Children's Hospital San Francisco.

Fullerton noted that this study expands on an earlier study by her group with similar findings. The current study has a larger sample size, broader geographic representation, prospective enrollment and central review of brain imaging to confirm the stroke cases.