| Study characteristics |
| Methods |
Prospective cohort study conducted in Milan, Italy during the 2000 to 2001 influenza season, in the community. Data sources were: monthly phone interviews and self administered questionnaires. Follow‐up period was 30 November 2000 to 31 March 2001. |
| Participants |
363 community‐dwelling elderly (264 treated and 99 controls; 184 and 79 included in the analysis, respectively), mean age 75 years |
| Interventions |
Adjuvant virosomal vaccine. Vaccine strains probably matched the circulating strain. |
| Outcomes |
Clinically defined ILI (fever + at least 1 systemic symptom: headache, myalgia, chills, weakness + at least 1 respiratory symptom: cough, sore throat, congestion); acute respiratory infection (respiratory symptoms without immediate fever); hospitalisation for pulmonary infection |
| Notes |
Low viral circulation. Cohorts were not significantly different as comorbidity. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
High risk |
C ‐ Inadequate |
