| Study characteristics |
| Methods |
Authors investigated an outbreak in a nursing home in Wyoming, USA during the 1984 to 1985 influenza season. Follow‐up period was 2 January 1985 to 3 March 1985. Throat washing and convalescent sera were obtained from some residents. |
| Participants |
55 nursing home residents (36 treated and 19 controls, all included in the analysis), 60 to 98 years old |
| Interventions |
Parenteral influenza vaccine: A/Philippines/82; A/Chile/83; B/USSR/84. Vaccine strains probably matched circulating strains. |
| Outcomes |
Clinically defined URI (upper respiratory illness: fever, chills, myalgia, respiratory symptoms), radiologically confirmed pneumonia, hospitalisation, and death without further specification |
| Notes |
Amantadine was used in cases. The circulating strain that year was of A/Philippines type. No virus strain was isolated from participants, but serologic tests confirmed influenza A virus infections. Poor description of methods |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
High risk |
C ‐ Inadequate |
