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

Intussusception and Rotavirus Vaccine

The original rotavirus vaccine—Rotashield®—was shown to have caused intussusception at a rate of about 1 in 10,000 infants. What about the new vaccine?


Vaccine Components

Aluminum Adjuvants in Vaccines

Some vaccines contain chemicals called adjuvants to help stimulate the production of immunity against the vaccine ingredients, making the vaccine more effective. In the United States, aluminum salts have frequently been incorporated as adjuvants in vaccines.