Childhood vaccines protect even the unvaccinated

Giving children the flu vaccine can protect the wider community, study finds.

It’s obvious that giving a child the flu vaccine will protect him or her from the influenza. But a new study suggests the benefit of vaccinating children can extend well beyond the youngsters themselves. Results of a clinical trial conducted in a largely self-contained religious community during the 2008-09 flu season show that vaccinating children against the seasonal flu can significantly protect unvaccinated community members as well. The study was conducted to determine if children who received the vaccine could act as a barrier to limit the spread of the flu to the wider, unvaccinated community, a concept known as “herd immunity.”

According to the National Institutes of Health, researchers recruited volunteers from 46 Canadian Hutterite religious colonies that have limited contact with surrounding, non-Hutterite populations. (Hutterite communities have a lifestyle similar to the Amish and Mennonites). Of the close to 1,000 children participating in the study, roughly half were given the flu vaccine, while the other half were give the hepatitis A vaccine, which served as the control. The researchers found that the flu vaccine was 61 percent effective at indirectly preventing illness in unvaccinated people if they lived in a colony where approximately 80 percent of the children had received the flu vaccine.

The researchers further suggested that giving school-aged children the flu vaccine could be an effective way to stop the spread of the flu. In a statement provided by the National Institutes of Health, the researchers wrote “it may be advantageous to selectively immunize children in order to reduce community transmission of influenza.”

It’s not clear if the study gives license to assert the converse: Not giving your child the flu vaccine can actually harm others. But it’s certainly something to think about. I’m not ready to require that parents go out and get the flu vaccine for their kids as a requirement to attend public school. I do wonder if that might someday be the case for the swine flu, which cut a respectable swath of school closings across New York City last year. (In an open letter earlier this year to health care providers across the country, federal Commissioner of Food and Drugs Margaret A. Hamburg warned doctors of a “significant” chance that the swine flu will return later this flu season after showing recent signs of waning). We certainly do require other vaccines in order to attend school, despite some lingering fears among parents of their safety. In any case, I will take the opportunity here to suggest that taking care of yourself, which can include getting yourself vaccinated against the flu, is an act you owe not only yourself, but others in our society as well. I don’t want to legislate healthful habits, but I also think there’s something to be said for keeping healthy as a means of reducing health care costs and increasing productivity.

What do you think?

Photo Credit: UNICEF Sverige