Safety and tolerability of bivalent HPV vaccine: an Italian post-licensure study

One of the most important scientific discoveries of the last century was that persistent infection by some types of HPV is a precondition for the development of cervical cancer. The oncogenic types of HPV are also associated with other tumours (vaginal, vulvar and anal carcinomas, tumours of the head and neck, urethra and penis). Two preventive vaccines are currently available (Cervarix and Gardasil). Both have shown very good efficacy, safety and tolerability profiles. Nonetheless, extensive vaccination requires long-term monitoring of safety and tolerability. The aim of our study was to evaluate the safety and tolerability of the bivalent vaccine Cervarix in Italy. Every participant in the study completed a questionnaire after each dose of vaccine received, with a view to recording adverse events during the first 7 days after vaccination. We registered local (pain, redness, swelling) and systemic symptoms (fever, headache, myalgia, fatigue, arthralgia, itching, gastrointestinal disorders, rash and urticaria). A total of 4,643 subjects were recruited. In all, 7,107 questionnaires were collected: 3,064 after the first dose, 2,367 after the second and 1,676 after the third. No serious adverse events were observed. The most frequent local symptom was pain at the injection site, while fatigue, headache and myalgia were the most common systemic reactions. Pain was reported more frequently after the first dose than after the others, while all the other local and general symptoms were reported most frequently after the third dose. Almost all of the local and general reactions proved to be of negligible intensity and duration and required no medical intervention. Our results show better tolerability of the vaccine in comparison with the data from some controlled clinical studies and from other surveillance programmes conducted internationally. That tolerability proved to be better than in clinical studies could be explained by the absence of the typical apprehension felt by subjects involved in clinical experimentation.