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. All data were included in a separate analysis. |
Participants |
259,627 community‐dwelling elderly (100,242 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; pneumococcal vaccine. Vaccine strains matched the circulating strain. |
Outcomes |
Hospitalisation from influenza (ICD‐X: J10.0, J10.1, J10.8, J11.0, J11.1, J11.8), deaths from influenza, hospitalisation from pneumonia (ICD‐X: J12‐ J18, J69.0, A48.1), deaths from pneumonia; all deaths |
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 |