A study, featured in the Daily Mail, suggests a link between certain types of flu and risk of Parkinson's.
The US research, published last year in the scientific journal npg Parkinson's Disease, investigates the combined effects of flu and a toxin that specifically damages dopamine producing brain cells.
The researchers found was that mice infected with the H1N1 strain of flu, showed a 20% greater loss of these cells when treated with the toxin called MPTP.
They also showed that this increased loss of brain cells, due to the combined effects of flu and toxin, could be reduced by vaccinating the mice against flu.
Multiple factors working together
The causes of Parkinson's are complex. But, in most cases, a combination of multiple factors are likely to be involved.
These factors are believed to play a more significant role together than individually - this is known as the 'multi-hit' hypothesis.
Could the Flu jab help prevent Parkinson's?
Researchers have previously shown that certain strains of flu can cause inflammation, which is believed to play a role in Parkinson's. But, as yet, there is no conclusive evidence that catching flu can increase the risk of developing Parkinson's in later life.
Here the researchers investigate the combined effect of the H1N1 flu strain and the toxin MPTP in mice. This strain of flu is quite different from the 'Aussie flu' strain H3N2 or other flu strains prevalent in the UK at the moment, and the research has yet to be replicated in humans.
More research is needed to investigate whether flu increases risk of Parkinson's in people and whether receiving a seasonal flu vaccine may help reduce risk of developing the condition.
Professor David Dexter, Deputy Director of Research at Parkinson's UK, comments:
"This study supports anecdotal evidence that major viral infections, such as the flu, can act as a tipping point, or speed up the onset of Parkinson's for those who have the condition but don’t yet know they have it.
"This study also shows that a flu injection, for some, may reduce the damage that could be caused by multiple factors acting alongside each other.
"While a lot of exciting research is happening in this area, we still do not fully understand the causes of Parkinson's and for most people, it is unlikely that a single factor is to blame. Rather, various lifestyle, environmental and genetic factors combine to bring it about."