| Study characteristics |
| Methods |
Authors investigated an outbreak in a skilled nursing home, in Connecticut, USA, during the 1984 to 1985 influenza season; medical records were reviewed. Follow‐up period was 15 January 1985 to 15 February 1985. Throat swab and paired sera specimens were obtained from some ill residents. |
| Participants |
85 residents (30 treated and 55 controls, all included in the analysis), 33 to 95 years old |
| Interventions |
Parenteral influenza vaccine: A/Philippines/2/82; A/Chile/83; B/USSR/100/83. Vaccine strains probably matched circulating strains. |
| Outcomes |
Clinically defined ILI (fever 37.8 °C or greater, cough, coryza, sore throat); hospitalisation from ILI; deaths occurring within 2 weeks of ILI with no other explanation |
| Notes |
9 days after the outbreak started amantadine prophylaxis was given to most of the remaining well residents. Successive outcomes were not accounted for. The circulating strain was related to A/Philippines/2/82. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Unclear risk |
B ‐ Unclear |
