OBJECTIVES:To identify the novel adverse events reported to VAERS database after HPV vaccination from July 2006 to May 2017 using disproportionality analysis

METHODS:A systematic data mining was performed in the VAERS database for reports associated with HPV vaccine, from July 2006 through May 2017. VAERS received 49444 reports associated to HPV vaccine within the aforementioned time period. Out of 49444, 2307 unique reactions were identified by removing the duplicate. Clinically relevant Vaccine Event Combinations (VEC) were identified in the VAERS database following HPV vaccination. We considered a VEC for analysis only if a minimum of hundred reports were present in database for the given Adverse Event (AE). This resulted in fifty-seven clinically relevant VECs by omitting 2250 VECs as those had reports below hundred. The AEs associated with HPV vaccine which were detected earlier (clinical trials) and those mentioned in product label were excluded from analysis as the relation was already established. The data mining algorithm used for disproportionality analysis was Reporting Odds Ratio (ROR). A value of ROR-1.96SE>1 was considered as positive signal.

RESULTS: A total of 174 death reports and 3361 non-death serious reactions (Life threatening, hospitalized, prolonged hospitalization and disability) were reported to VAERS associated with HPV vaccine. 96.22% of reports were from the age group of 9-26 years. ROR showed positive signals (novel adverse events) for Anogenital warts (ROR-1.96SE=137.755), Cervical dysplasia (87.544), Amenorrhoea (59.641), Syncope (15.149), Head injury (8.238), Alopecia (6.879), Loss of consciousness (6.791), Abortion spontaneous (5.509), Fall (4.735), Dizziness (3.192), Seizure (2.655), Migrane (2.388), Anaemia (2.191) and Dyskinesia (2.176).

CONCLUSIONS: The present analysis showed fourteen potential novel adverse events associated with HPV vaccine. Although a causal relationship cannot be established, the number of cases reported suggest that there might be an association. Further studies are required to systematically validate the data.