Aymard 1979b.

Study characteristics
Methods	Authors investigated an outbreak in a geriatric hospital in France during the 1977 to 1978 influenza season.
Participants	155 nursing home residents (85 treated and 70 controls, all included in the analysis)
Interventions	Bivalent parenteral vaccine: A/Vic/3/75; B/HK/1/73. Vaccine strains did not match circulating strains.
Outcomes	Disease and deaths without further specifications.
Notes	Part of a surveillance study conducted in several communities; poor description of methods; circulating strains were mostly A/Tex/1/77 like
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	D ‐ Not used