Vellozzi · Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 2014 · narrative review · n=?

Guillain-Barre syndrome, influenza, and influenza vaccination: the epidemiologic evidence.

Cited 211 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Narrative review of epidemiological literature without systematic review methodology.

PubMed 24415636 · doi:10.1093/cid/ciu005 · record verified 2026-08-31

What was done

This narrative review synthesized 35 years of epidemiological evidence examining the association between Guillain-Barré syndrome (GBS), influenza virus infection, and influenza vaccines (including the 1976 swine-influenza vaccine, seasonal vaccines, and the 2009 H1N1 monovalent vaccine).

What was found

No quantitative effect sizes or risk ratios are reported in the abstract. The authors report qualitatively that GBS is preceded by upper respiratory or gastrointestinal infection in about two-thirds of cases, that seasonal and 2009 H1N1 vaccines show a small increased risk of GBS, and that the magnitude of GBS risk following wild-type influenza infection is several times greater than following vaccination.

Why it matters

It puts post-vaccination safety signals in clinical context by showing that natural influenza infection carries a considerably higher relative risk of triggering GBS than vaccination.

Limits

The abstract describes a narrative review with no systematic search criteria, meta-analytic pooling, study count, or sample sizes reported. No precise effect estimates or confidence intervals are provided, and the extreme rarity of post-vaccination GBS limits precise risk estimation.

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