Inclusion criteria | Exclusion criteria |
---|---|
1. Aged 18 or above. | 1. Participants who did not complete registration process [excluded before randomization]. |
1. Access to the Internet, and email at least on a monthly basis. | 2. Participants who self-reported having obtained an influenza vaccination in 2010 prior to enrolment in the study [excluded from analysis]. |
 | 3. Participants who self-reported to be influenced by other participants during the study to obtain (or not obtain) influenza vaccination [excluded from analysis]. |