Aymard 1979a.

Study characteristics
Methods	Authors investigated an outbreak in a geriatric hospital in France during the 1976 to 1977 influenza season.
Participants	100 nursing home residents (50 treated and 50 controls, all included in the analysis)
Interventions	Bivalent parenteral vaccine: A/Vic/3/75; B/HK/1/72. Vaccine strains matched 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/Vic/3/75 like
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	D ‐ Not used