Effectiveness of influenza vaccine in preventing influenza-like illness among Faculty of Dentistry staff and students in Universiti Kebangsaan Malaysia

Abstract

Influenza is a highly contagious respiratory disease and potentially hazardous for patients and dental personnel in dental clinics. The objective of this study was to evaluate the effectiveness and safety of influenza vaccine among the staff and students of the Faculty of Dentistry, Universiti Kebangsaan Malaysia. The project was conducted from Mayto September 2005. Atotal of 346 participants volunteered for the study and were assigned randomly to a vaccination (170) and control group (176). Participants in the vaccination group were given influenza vaccine for the southern hemisphere season 2005. Demographic data of the participants, data on adverse effects after vaccination and occurrence of influenza-like illness (ILI) were obtained through questionnaires. Results showed that vaccination significantly reduced ILI prevalence by 52.6% (P=0.002). Frequency of recurrence of the ILI episode, absenteeism and visits to doctors among the vaccinated group were 77.0% (P=0.031), 76.1% (P=0.001) and 52.7% (P=0.004), respectively. Vaccination also provided indirect protection to family members or housemates of the vaccinated participants, with 71.6% effectiveness (P=0.026). The most common adverse event reported by vaccinated individuals was pain at the site of injection. In conclusion, influenza vaccine is safe and beneficial for dental staff and students. Annual influenza vaccination of dental staff, students and other healthcare workers who have direct contact with patients should be encouraged.