JMIR Publications

ABSTRACT

Background:

Despite the introduction of the HPV vaccination as a preventive measure in 2006, uptake rates remain suboptimal, resulting in preventable cancer mortality. Social media, widely used for information seeking, has been shown to be influential on users’ knowledge and attitudes regarding HPV vaccination. Little is known regarding attitudes related to HPV vaccination on Reddit (a popular news aggregation site and online community), particularly related to cancer risk and sexual activity. Examining HPV vaccine related messages on Reddit may provide insights into how HPV discussions are characterized online and influence decision-making related to vaccination.

Objective:

We seek to observe how the HPV vaccine is characterized on Reddit over time and by user gender. Specifically, we seek to determine if: 1) Reddit messages are more related to cancer risks or sexual behavior; and 2)what other topics characterize the discussion on HPV vaccination on Reddit.

Methods:

We gathered all public Reddit comments from January 2007 through September 2015. We manually annotated 400 messages to generate keywords and identify themes. We then measured the similarity between each comment and lists of keywords associated with sexual behavior and cancer risk, using Latent Semantic Analysis (LSA). Next, we used Latent Dirichlet Allocation (LDA) to characterize remaining topics within the Reddit data.

Results:

We analyzed 22,729 messages containing the strings “hpv” or “human papillomavirus” and “vaccin”. LSA findings showed that Reddit HPV vaccine discussions are significantly more related to cancer compared to sexual behavior. Compared to women, men were similarly more likely to discuss cancer risks between 2007 (mean LSA similarity score=0.14 for men, 0.13 for women,) and 2015 (mean LSA similarity score=0.10 for men, 0.09 for women). LDA analyses demonstrated that although topics related to cancer risk (16.1%) and sexual activity (14.5%) were both widely discussed, the majority of online discussions talked about neither of these. The most frequently discussed topic was politics associated with the vaccine (17.2%). Other topics included HPV disease/immunity (13.5%), the HPV vaccine schedule (11.5%), HPV vaccine side effects (9.7%), hyperlinks to outside sources (9.1%), and the risks and benefit of HPV vaccination (8.5%).

Conclusions:

Reddit discourse on HPV vaccine encompasses a broad range of topics among men and women, with HPV political debates and cancer risk making up the plurality of the discussion. Our findings demonstrated that women and men were equally likely to discuss HPV, highlighting that Reddit users do not perceive HPV as a female only issue. Given the increasing use of social media as a source of health information, these results can inform the development of targeted online health communication strategies to promote HPV vaccination to young adult users of Reddit. Analyzing online discussions on Reddit can inform health communication efforts by identifying relevant, important HPV related topics among online communities.