Table 2. Key studies selected in our review.

GBS: Guillain Barré syndrome

Author name	Publication Month-Year	Type of Study	Focus of study	Result / Conclusion
Sanz et al [5]	August 2019	Systematic literature review	Assess the risk of GBS after Pandemic & Seasonal influenza vaccine	GBS should be considered less common adverse event following influenza vaccine but it should affect vaccine acceptance.
Petras et al [8]	March 2020	Meta-analysis	Risk of GBS following seasonal influenza vaccine	The meta-analysis did not find association between GBS & seasonal influenza vaccine
Gattas et al [9]	December 2018	Retrospective observational	GBS & Seasonal trivalent influenza vaccine association	Post vaccination GBS is rare but should be monitored closely by health authorities
Bardenheier et al [11]	August 2018	Retrospective observational	Compare adverse event following pandemic and seasonal influenza vaccine in military vs civilian population aged 17-44 years	Incidence of GBS is four times higher in military population than civilian population.
Park et al [15]	July 2017	Retrospective Observational	Clinical and Laboratory features of GBS after influenza immunization	GBS should be suspected six weeks following immunization in the absence of clear alternative diagnosis to improve diagnostic accuracy and Brighton criteria is used for evaluation of post-vaccine GBS.
Dieleman et al [18]	July 2011	Case-control	Assess the risk of GBS after H1N1 pandemic influenza vaccine	No risk of GBS after the pandemic influenza vaccine when adjusted with influenza like illness and seasonal influenza vaccine.
Kuo et al [21]	July 2019	Case control	Association between GBS & Trivalent influenza vaccine in patient aged >50 years	Trivalent influenza vaccine has no association with GBS after 50 years of age
Prestel et al [27]	November 2014	Case series	Risk of GBS & variant Fisher syndrome following H1N1 pandemic influenza vaccine	High risk of GBS & Variant Fisher syndrome in temporal association with pandemic influenza vaccine