Prophylaxis for meningococcal infection (Neisseria meningitides) with vaccination, and antibiotics if treatment with eculizumab cannot be delayed until vaccine response. Per manufacture's instructions:
Comply with the most current Advisory Committee on Immunization Practices (ACIP) recommendations for meningococcal vaccination in patients with complement deficiencies. Immunize patients with meningococcal vaccines at least 2 weeks prior to administering the first dose of eculizumab, unless the risks of delaying eculizumab therapy outweigh the risk of developing a meningococcal infection.  If urgent eculizumab therapy is indicated in an unvaccinated patient, administer meningococcal vaccine(s) as soon as possible and provide patients with two weeks of antibacterial drug prophylaxis.