A study of over 9,000 urban minority children shows that sending text messages to their parents can increase the number of children who receive flu vaccinations.

The increase was modest, with the flu vaccination rate rising from 39.9% to 43.6%. Among parents who actually received the text messages, the vaccination rate rose to 46.3%

Some people even described the text messages as an angel on their shoulder.

Text messaging is becoming more and more valuable as a health tool. In a 2010 study, personalized text messages more than doubled the success of cigarette smokers who were trying to break the habit. Some people even described the text messages as an angel on their shoulder. And while the results from the flu study aren't as striking, they show more success than traditional mail and phone reminders have at increasing the vaccination rate.

Despite urging from the American Academy of Pediatrics, people, especially children, still aren't getting their yearly flu shot. The CDC estimates that only 51% of children and adolescents six months to 17 years old were vaccinated in the 2010-2011 flu season. And flu vaccination rates in the past have been even lower in low-income areas. Traditional vaccine reminders have been largely ineffective at raising this rate.

This study tested the effect of targeted text messages to low-income, urban parents on the flu vaccination of their children. It looked at parents of 9,213 children and adolescents aged six months to 18 years who were receiving care at four community-based clinics in the United States during the 2010-2011 flu season.

Half of the families received usual care, which included an automated telephone reminder to the parents to have their child vaccinated for the flu. The other half also received up to five weekly text messages providing educational information and instructions on where vaccinations were available.

The first three text messages provided general information about vaccines, including vaccine safety information. They also emphasized the seriousness of flu infections, with messages tailored to the age of the child or adolescent. The last two messages informed families about dates for Saturday flu vaccine clinics, which were held weekly from October 2010 through March 2011.

As with any new technology, there were some bugs in the system. Around 14% of the parents never received the text messages, either because of a wrong phone number, messaging incompatibility or other reason.

When telephones first began to be installed in doctors' offices, there were some hiccups that made phones seem more of a nuisance than a technological advance. Today, it's hard to imagine a doctor's office without one. Text messaging's ability to reach large numbers of people at low cost offers as many possibilities for improving public health and for simplifying doctor-patient communication as the telephone did. A major challenge in realizing this potential is likely to be designing text messages that are effective. That will probably require a lot more fine-tuning than fixing the technical glitches will.

An article on the study appears in The Journal of the American Medical Association (JAMA).