Duplicates removed	73
Excluded during initial screening (e.g. press releases; news reports; not relevant drug/indication; preclinical study; reviews; case reports; not randomized trial)	79
Excluded during writing (e.g. reviews; duplicate data; small patient number; nonrandomized/phase I/II trials)	34
Cited efficacy/tolerability articles	19
Cited articles not efficacy/tolerability	21
Search Strategy: EMBASE, MEDLINE and PubMed from 1946 to present. Clinical trial registries/databases and websites were also searched for relevant data. Key words were Flucelvax TETRA, Flucelvax Quadrivalent, Optaflu, influenza vaccine. Records were limited to those in English language. Searches last updated 9 July 2019