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

Post-Polio Syndrome, Vaccine-Associated Paralytic Polio and Poliomyelitis Elimination

Recently an unimmunized child was reported from Minnesota with poliovirus infection. So far, three other unimmunized children in the same community have also been identified as being infected. What is the origin of these infections?

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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.

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