Immunization Issues

Evaluating Information About Vaccines on the Internet

Updated: July 12, 2010

How do I know if the vaccine information I find on the Internet is accurate?

The Internet can be a valuable resource to find health information. However, the quality of health information on the Internet is extremely variable and difficult to assess. General search engines only identify topics and provide the lists of Web sites that include good sites as well as misinformation.

Remember that medical information changes rapidly so it is a good idea to check more than one place for information. Here are some suggestions for getting started:

First, start with a source that you know provides reliable information and which can direct you to other reliable sources of information. For example:

  • The National Library of Medicine’s Medline Plus is one of the best places to begin a search about health matters.
  • The Centers for Disease Control and Prevention (CDC) is the lead federal agency for protecting the health and safety of people–at home and abroad. Its Web site provides a wealth of information about health, travel, the environment and disease prevention.
  • The National Institutes of Health is the steward of medical and behavioral research for the US. A great deal of information on health issues can be found at as well as at the Web sites of the 27 Institutes and Centers,
  • The World Health Organization (WHO) is the United Nations agency for health. A global perspective on many health issues may be found there.
  • American Academy of Pediatrics (AAP) covers a wide range of information about children’s health.
  • Tufts University Child & Family WebGuide was developed by a group of faculty to create an evaluation instrument for information about children. The site is divided into various categories of information: family/parenting, education/learning, typical child development, health/mental health, resources/recreation and medical pages.

When you go to a site look for these characteristics:

  • A good health Web site will display who is responsible for the site. Also, there will be a way to contact the information provider or Webmaster.
  • Information should not be slanted in favor of a Web site’s sponsor or source of funding. Health information should be accurate and unbiased.

Then, ask the following questions:

  • Do scientific experts review the medical information before it is posted on the Web site? What are their credentials? Remember that credentials are difficult to assess on the Internet and experts in one field may not be experts in another area. It is important to look for sponsoring organizations that allow their name and prestige to be displayed. For example, notice the organizations that allow this Web site to display their names and logos.
  • Does the information display the date of last revision, and is it kept up to date?
  • What is the scientific evidence for claims made? The original source of facts and figures should be shown. For example, the Web site should provide citations of medical articles or other sources of information. You should be able to distinguish facts from opinions. Also, facts are more reliable if they come from a published scientific study on humans rather than from unpublished accounts or from reports of a single person or of animal studies. One needs to recognize, however, that many of the anti-vaccine sites appear legitimate and cite articles from CDC and other reliable sources but either misquote or take a statement out of context. Web sites may inaccurately cite published literature.
  • Does the Web site feature anecdotes (stories about individuals) about purported serious adverse events instead of scientific evidence? If so it is likely not a credible source of information.

Next, consider the purpose of the Web site. The purpose should be to provide accurate and unbiased information about that topic. If the purpose is to advertise about a health care product, be skeptical about the information provided. If much of the material on the Web site emphasizes stories about individual children, it may be an anti-vaccine Web site.

Finally, discuss with your health professional the information that you find on the Web. Health information found on the Web should supplement rather than replace the information or advice given by your health care provider.

Trustworthy information about vaccines

  • National Network for Immunization Information (NNii)
    The NNii Web site is designed to provide health care professionals, the media, policy makers, and the public with up-to-date, science-based information on immunizations. The site features a searchable database of information on diseases prevented through immunization, a listing of all state vaccination requirements, and thrice-weekly Immunization Newsbriefs, which highlight vaccine issues in the news. It also includes background on vaccine development and vaccine safety, guidelines for how to evaluate health information on the Internet, and an image gallery of the effects of vaccine-preventable diseases. The NNii Resource Kit, Communicating With Patients About Immunization, is also available here in downloadable PDF format.
  • CDC Vaccines & Immunizations
    The Centers for Disease Control and Prevention’s Website on vaccines features a section designed for parents with publications such as the “Parent’s Guide to Childhood Immunizations” and “Some Common Misconceptions” about vaccination. Also provided are the recommendations of the Advisory Committee on Immunization Practices (ACIP) and downloadable Vaccine Information Statements (VIS).
  • Immunization Action Coalition (IAC)
    This site is most suited for health professionals, but many aspects of it will be informative for parents. For example, it includes sections that summarize the effects of vaccine-preventable diseases, including personal accounts of people who have been affected by them. Visitors can view photos of people with vaccine-preventable diseases and review state immunization mandates. A listserv called IAC Express is available on the site, which provides regular notices about current immunization topics. In addition, the site provides CDC’s Vaccine Information Statements in 26 languages, including English.
  • World Health Organization (WHO) Immunization Safety & Global Advisory Committee on Vaccine Safety
    This site’s section on vaccine safety educates visitors on current immunization issues and how vaccines are developed and distributed. It displays immunization statistics, maps, and charts. The site also describes the Global Alliance for Vaccines and Immunization (GAVI). WHO’s perspective is global and site contents also are available in Spanish and French.

More sites >>


  • Health Summit Working Group. (1998). Criteria for assessing the quality of health information on the Internet: Policy paper. McLean, VA: Mitretek Systems.
  • World Health Organiztion: Global Advisory Committee on Vaccine Safety (GACVS). Good information practices for vaccine safety web sites.
  • Wyatt JC. (1997). Commentary: Measuring quality and impact of the world wide web. Brit Med J 314:1879-1881.