Type of tweet

Health professional user: tweets posted by health professionals

Parent audience: tweets posted with content for parents, messages intended to reach parents

Health professional to parent: tweets posted by health professionals for a parent audience

Tweet content

Resource/information: objective information about the HPV vaccine with supporting source

Personal experience/opinion: story or opinion about HPV, no factual sources

Joke or parody: humorous/satirical statement about HPV

Other: tweet does not satisfy the above categories

Tweet characteristic

Side effects: mention of side effects caused by the HPV vaccine

Prevention/protection: describes how HPV vaccine will protect or prevent negative health outcomes

Risk/prevalence of HPV: details risk of contracting HPV or the prevalence of HPV

Men/boys: tweet refers to men or boys along with HPV

Women/girls: refers to women or girls along with HPV

Tweet sentiment

Positive: supportive messages about the HPV vaccine and encourages its uptake

Negative: disparaging messages about the HPV vaccine and/or discourages it uptake

Neutral: no opinions about vaccine, facts repeated

No mention: HPV vaccine is not mentioned