FACTORS AFFECTING EFFECTIVENESS OF INFLUENZA VACCINE AMONG DENTAL STAFF AND STUDENTS OF UNIVERSITI KEBANGSAAN MALAYSIA

Influenza is a highly contagious respiratory disease and is a major infectious hazard for patients and dental personnel in dental clinics. The objectives of this study were to evaluate the effectiveness of influenza vaccine among the staff and students of the Faculty of Dentistry, Universiti Kebangsaan Malaysia (UKM) and the factors affecting it. A total of 346 participants volunteered for the study and were assigned randomly into a vaccination group (170) and control group (176). Participants in the vaccination group were given a shot of influenza vaccine for the southern hemisphere season 2005. Demographic data of the participants, data on adverse effects post-vaccination and occurrence of influenza-like illness (ILI) were obtained by means of 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. Men experienced significantly higher incidence of ILI compared to females (p=0.035). Staff with less than 1 year of employment had lower incidence of ILI after vaccination compared to those with longer period (p=0.026). In conclusion, influenza vaccine is effective and beneficial for dental staff and students and its
effectiveness is affected by gender and duration of employment. Annual influenza vaccination of health care workers should be encouraged.