The NIS is an annual survey conducted by the CDC in two parts. First, homes with children between 19 and 35 months of age are randomly selected and parents complete a telephone survey to answer questions about which vaccines their toddlers have received. Second, with parental permission, healthcare providers of these children are mailed a survey to confirm parental recollections. Only with both sets of information is a child included in the analysis. A child is not individually identified in the analysis; rather the data are reviewed collectively.
The NIS provides the following information:
The information collected in the NIS is important for understanding the likelihood of certain diseases spreading throughout the country, which vaccines are being used, at what rate, and by whom.
Since most families only hear about the NIS data in the media reports that immediately follow its release, they will go away feeling comfortable that vaccine coverage rates are sufficient in the U.S., and for the most part they are correct. Indeed for most vaccines, immunization rates in this country are high enough to stem outbreaks. Unfortunately, national rates do not tell the entire story because there are pockets of unvaccinated or undervaccinated people throughout this country that make some communities more susceptible to outbreaks than others.
Updated: January 2013
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