Roughly in line with other people's experiences: I never had a flu jab before diagnosis; I've had them every year since, with no known side-effects.

I've not had the flu since having the shots. I only had the flu once before diagnosis. (Until I had the real thing, which was qualitatively different from anything that I'd had previously, I thought wrongly that I'd had the flu on an almost annual basis). That was approximately 15 years before diagnosis.

My Parkinson's nurse is keen that PwP get the jab because she reckons that getting the flu can lead to a step change in PD symptoms.

Rohn and Catlin report [1]:

"We present immunohistochemical data indicating the presence of influenza A virus within the substantia nigra pars compacta (SNpc) from postmortem PD brain sections. ... The presence of influenza A virus together with macrophages and T-lymphocytes may contribute to the neuroinflammation associated with this disease."

A study by Smeyne, funded by MJFF reports [2]:

"Our results suggest that a pandemic H5N1 pathogen, or other neurotropic influenza virus, could initiate CNS disorders of protein aggregation including Parkinson’s disease."

[As an aside, given the weight of evidence that alpha-synuclein misfolding is implicated in the pathogenesis of PD, nowadays before commenting on whether anything, let's call it X, is associated with PD, I usually do a sanity check to see if there is any evidence that X and alpha-synuclein are associated.]

Reference:

[1] Rohn TT, Catlin LW (2011) Immunolocalization of Influenza A Virus and Markers of Inflammation in the Human Parkinson's Disease Brain. PLoS ONE 6(5): e20495. doi:10.1371/journal.pone.0020495
http://www.plosone.org/article/info%...l.pone.0020495

[2] Smeyne R
https://www.michaeljfox.org/foundati...p?grant_id=500

John