Is the influenza vaccination rate of elderly patients affected by raising the vaccination rate of the staff at their primary health care clinics?

Abstract

Background: Influenza vaccination of community-dwelling elderly is widely recommended. Observational studies have shown a strong association between physicians' personal vaccination status and their reported level of recommendation to patients and possibly their patients' actual vaccination. No published trials have examined whether increasing vaccination rates of primary care staff raises vaccination among their patients. Proof of a positive effect would support the notion that vaccinating health care workers benefits their patients.

Objectives: To examine whether an intervention to increase staff vaccination also increases vaccination of their patients aged 65 and over.

Methods: A trial examining an intervention aiming to raise staff immunization rates was performed in primary care community clinics in the Jerusalem area. The study population comprised the staff of 13 randomly chosen intervention clinics during the season of 2007-2008, with another 14 clinics serving as controls. The intervention resulted in a staff vaccination rate of 52.8% compared to 26.5% in the control clinics (66.1% and 32.2% among physicians). No intervention was directed at the patients. Data on patient vaccination and other patient characteristics were extracted from the health funds' computerized databases.

Results: The percentage of patients vaccinated during the intervention season was 57.8% in both intervention and control groups, reflecting an increase of 14.4% compared to the previous season in the intervention clinics and of 13.4% in the control clinics. Logistic regression demonstrated a statistically significant association between intervention and patient vaccination with an odds ratio of 1.10 (95% confidence interval 1.03-1.18). However, analysis adjusting for clustering did not show a significant association.

Conclusions: Increasing influenza vaccination of the medical staff did not substantially increase patient vaccination. These results do not show any patient benefit from staff vaccination in primary care.