 Eculizumab carries a black box warning for the risk of meningococcal infections and can only be prescribed by doctors who have enrolled in and follow a risk evaluation and mitigation strategy required by the FDA, which involves doctors counseling people to whom they are prescribing the drug, giving them educational materials, and ensuring that they are vaccinated, all of which must be documented.Eculizumab inhibits terminal complement activation and therefore makes people vulnerable to infection with encapsulated organisms.Life-threatening and fatal meningococcal infections have occurred in people who received eculizumab.