A total of 600,558 HPV4 doses were administered during the study period. We found no statistically significant increased risk for the outcomes studied. However, a non-statistically significant relative risk (RR) for VTE ICD-9 codes following HPV4 vaccination of 1.98 was detected among females age 9–17 years. Medical record review of all 8 vaccinated cases in this age group revealed that 5 met the standard case definition for VTE and all cases had known risk factors for VTE (oral contraceptive use, coagulation disorders, smoking, obesity or prolonged hospitalization).