The Centers for Disease Control and Prevention recently issued updated recommendations to prevent meningococcal disease in patients who are prescribed eculizumab, a drug used to treat two rare blood disorders. CDC recommends health care providers consider antimicrobial prophylaxis for the duration of eculizumab therapy; administer meningococcal vaccine two weeks prior to the first dose of the drug; and maintain a high index of suspicion for meningococcal disease in patients who present with symptoms.