| Study characteristics |
| Methods |
Prospective cohort study conducted in Stockholm, Sweden during the 1998 to 1999 influenza season, in the community. Data sources were vaccination database and discharge diagnoses database. Follow‐up period was 1 December 1998 to 31 May 1999. 23% of vaccinees received flu vaccine alone; 76% of vaccinated received flu and pneumococcal vaccine. 841 participants had only pneumococcal vaccine. Only flu vaccinated were included in analysis. |
| Participants |
182,609 community‐dwelling elderly (23,224 treated and 159,385 controls included in the analysis), 65 years or older |
| Interventions |
Parenteral influenza vaccine: A/Beijing/262/95; A/Sydney/5/97; B/Harbin/7/94. Vaccine strains matched the circulating strain. |
| Outcomes |
Hospitalisation from influenza (ICD‐X: J10.0, J10.1, J10.8, J11.0, J11.1, J11.8), hospitalisation from pneumonia (ICD‐X: J12‐ J18, J69.0, A48.1); deaths from influenza and deaths from pneumonia were not available for this comparison |
| Notes |
Vaccinated people had higher education, more underlying diseases, and smoked less. Circulating strain was A/Sydney (H3N2). The season was probably an epidemic one. 6% of the population lived in a nursing home. The study controls for age in analysis. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Unclear risk |
B ‐ Unclear |
