This study was conducted to explore a telephone-based approach for identifying and quantifying the occurrence of adverse events following immunization (AEFIs) during an MF59®-adjuvanted H5N1 vaccination program in Taiwan. From March to August 2011, each H5N1 vaccine recipient who voluntarily registered as participants within 72 h of vaccination was phone interviewed at postvaccination 7-10 and 21-24 d. Among the 292 participants, 270 and 263 interviews were completed at 7-10 and 21-24 d. Overall, 127 (48%) respondents reported local and 86 (33%) reported systemic reactions. Females (odds ratio [OR] 2.06, 95% confidence interval [CI] 1.18-3.63), nonelderly adults aged 18-59 y (OR 3.08, 95% CI 1.11-9.45), and first-dose recipients (OR 2.16, 95% CI 1.22-3.86) were independently associated with having an AEFI within the first 7-10 d. None of the AEFIs reported were serious adverse events. In conclusion, most AEFIs to H5N1 vaccine were anticipated but varied with sex, age, and vaccine dose number. The use of modern information technologies will be a scalable alternative to efficiently enroll and monitor recipients with possible AEFIs in large campaigns involving influenza or other emerging vaccines. Further studies should compare the detection of AEFIs using telephone monitoring and standard pharmacovigilance reporting.
Keywords: H5N1 influenza vaccine; MF59 adjuvant; Taiwan; postmarketing surveillance; vaccine safety.