| Study characteristics |
| Methods |
Prospective cohort study conducted in Hawaii during the 1996 to 1997 influenza season, in the community. Data source was insurance claim records. Follow‐up period was 15 November 1996 to 31 March 1997. Only 10% of vaccinated participants and 3% of unvaccinated participants received pneumococcal vaccination. |
| Participants |
77,951 person periods members of a medical care programme (44,271 treated and 33,680 controls, all included in the analysis), 65 years or older |
| Interventions |
Parenteral influenza vaccine. Vaccine strains probably matched the circulating strain (literature data). |
| Outcomes |
Hospitalisation from pneumonia and influenza (ICD 480‐487), hospitalisation from all respiratory conditions (ICD 460‐462, 465‐466, 480‐487, 500‐518), hospitalisation from congestive heart failure (ICD 428) |
| Notes |
Odds ratios were adjusted by age and health status. Frequencies data were not available. To perform quantitative analysis, adjusted data were used. The season was probably an epidemic one. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Low risk |
A ‐ Adequate |
