Cervical cancer, the human papillomavirus vaccine, and cervical screenings from 2004—2021: a Google Trends analysis in Japan

Abstract

Background The World Health Organization (WHO) established a global strategy to accelerate the elimination of cervical cancer in 2020; fortunately, it can be effectively controlled or prevented by the human papillomavirus (HPV) vaccine. Nevertheless, Japan has been experiencing an HPV vaccine crisis since 2013, with a vaccination rate of less than 1% lasting for seven years. We examined trend changes related to cervical cancer topics and assessed the feasibility and limitations of Google Trends as an indicator of public health surveillance. Methods We collected search query data from Google Trends and the annual number of cervical cancer cases from the National Cancer Center, Japan. We then conducted a chronological and geographical analysis of the public interest in the phrases “cervical cancer,” “HPV vaccine,” and “cervical screening” from 2004—2021. We calculated correlations between the annual number of cervical cancer cases and the search terms. We also detected change points in public search interest. Finally, we analyzed subregional-level search interest disparities. Results Japanese public search interest in “cervical cancer,” “HPV vaccine,” and “cervical screening” increased from 2010—2013. Subsequently, interest in “cervical cancer” and “cervical screening” remained stable and relatively high, while interest in “HPV vaccine” was suddenly minimal. The actual number of cervical cancer cases showed a strong correlation with search volumes for “cervical screening” (r = 0.953, p < .001) and “cervical cancer” (r = 0.898, p < .001), respectively. In 2020, the public reignited its interest in “HPV vaccine.” We detected six change points in these three topics around 2010, 2013, and 2020, which aligned with critical policy decisions. Prefectures’ public interest levels were different for these three topics. Conclusions The Japanese public retained low interest in “HPV vaccine” from 2013—2020, while interest in “cervical cancer” and “cervical screening” terms was relatively high. Encouragingly, the public reignited its interest in “HPV vaccine” in 2020, which is expected to promote vaccination. Google Trends can extend unique perspectives for authorities to understand public concerns nearly synchronously, but it has a limited interpretation in subregions.