The National Network for Immunization Information (NNii) provides up-to-date, science-based information to healthcare professionals, the media, and the public: everyone who needs to know the facts about vaccines and immunization.
Vaccine Safety
Cause or Coincidence
When an adverse event occurs after vaccination, it needs to be determined whether the adverse event was caused by the vaccine or whether it was just coincidental in time with the administration of the vaccine—that is, it was going to happen anyway. How can researchers determine if a vaccine causes a particular disease or not?
For Professionals
This section includes links to general immunization recommendations in the United States and other valuable information for health professionals.
News
Updates
Emergence of Avian Influenza A(H7N9) Virus Causing Severe Human Illness — China, February–April 2013
Posted: May 6, 2013
Progress Toward Eradication of Polio — Worldwide, January 2011–March 2013
Posted: May 3, 2013