Background: Administration of the human papillomavirus (HPV) vaccine decreased dramatically in Japan after extensive news of adverse vaccine events and suspension of the governmental recommendation for the vaccine. In this study, we investigated the knowledge and acceptance of vaccinated adolescents concerning cervical cancer, cancer screening and the HPV vaccine. Furthermore, we analyzed whether and by how much the news affected acceptance of the vaccination.
Methods: This study was conducted as a part of Osaka Clinical resEArch of HPV vacciNe (OCEAN) study. A questionnaire was distributed to 2,777 study registrants.
Results: The response rate was 38%. The recognition rate of the news of the vaccine's adverse events was 80%; it was 68% for awareness of the government's announcement of the suspension of its recommendation for the vaccine. Among those who had a chance to hear or see the negative news during their vaccination period, 46 (60%) continued vaccination while knowing of the news, 22 (29%) discontinued vaccination, and 9 (11%) continued vaccination without an awareness of the news. Reports of the vaccine's adverse events were the main reason for not continuing the vaccination series. Those who consulted doctors after hearing the adverse news were significantly more likely to continue their vaccinations than those who did not.
Conclusions: Our results should help in understanding the need for a strong promotion of vaccine usage and cancer screening after future retraction of the recommendation suspension. This may apply to other countries with an unsatisfactory rate of HPV vaccination due to fears of adverse vaccine events.