CNN
Researchers with the University of Pennsylvania found that people who received text messages about the annual flu vaccine were more likely to get the shot. … Their findings, published in May in the journal Proceedings of the National Academy of Sciences, showed the texts boosted flu vaccination rates by an average of about 5%. It wasn't just the reminder that did the trick. The messages that performed best were those telling the patient that a vaccine was "reserved" or "waiting" for them.