Assessment of vaccination-related information for consumers available on Facebook

To assess the magnitude, interest, purpose and validity of vaccination-related information on Facebook and to determine whether information varies by site viewpoint.

The 10 largest vaccination-focused Facebook pages, groups and places in each category were identified and classified by viewpoint (i.e. anti-, pro-, neutral) and purpose. Number of members, posts per week, likes, comments and shares per post were recorded. Posts were assessed for concordance with CDC and FDA recommendations.

Of 30 sites, 43% (n = 13) were anti-vaccination, 7% (n = 2) neutral and 50% (n = 15) pro-vaccination. Most sites were most popular with American users. Median members were similar between anti-vaccination (2703 members, range 337-33 631 members) and pro-vaccination sites (2142 members, range 456-61,565 members, P = 0.262); however, anti-vaccination sites accumulated more posts per week by authors (median 15 vs. 3, P = 0.031) and members (median 33 vs. 1, P < 0.001). Pro-vaccination sites more commonly had commercial purpose (53% [n = 8] vs. 8% [n = 1], P = 0.02). Anti-vaccination sites more commonly gave medical advice (54% [n = 7] vs. 0%, P = 0.004). Overall, 48% (n = 22) of author posts were concordant with regulatory recommendations; concordance was more common on pro-vaccination sites (78% [n = 21] vs. 5% [n = 1], P = 0.0002).

Vaccination-related information is prevalent on Facebook regardless of viewpoint; however, anti-vaccination information generates more interest. Anti-vaccination sites were likely to provide medical advice and disagree with regulatory bodies.