Certain Medical Conditions as a Risk Factor

Certain medical conditions and medications may weaken the immune system and increase risk of meningococcal disease.

Persistent Complement Component Deficiencies

Ask your healthcare professional which meningococcal vaccines they recommend for you or your child.

CDC recommends people with a persistent complement component deficiency receive two vaccines for protection against meningococcal disease:

  • A meningococcal conjugate (MenACWY) vaccine
  • A serogroup B meningococcal (MenB) vaccine

Complement component deficiencies refer to disorders of the ‘complement system,’ which helps the body fight off infections. Examples of complement component deficiencies include C3, C5-9, properdin, factor H, and factor D. These disorders are very rare and usually genetic.

People who take complement inhibitors such as eculizumab (Soliris®) and ravulizumab (Ultomiris™) are also at increased risk for meningococcal disease.  Doctors most commonly prescribe complement inhibitors for three rare medical conditions:

  • Atypical hemolytic uremic syndrome (aHUS), a blood disorder
  • Paroxysmal nocturnal hemoglobinuria (PNH), a blood disorder
  • Generalized myasthenia gravis (MG), a disorder that leads to muscle weakness

Learn more about the risk of meningococcal disease among patients who take complement inhibitors.

Meningococcal Disease: What People Living with HIV Need to Know

Meningococcal Disease Fact Sheet: What People Living with HIV Need to Know pdf icon[2 pages]

This fact sheet describes common outcomes of meningococcal disease, a rare but very serious illness. People living with HIV are at increased risk for meningococcal disease and should get a meningococcal conjugate vaccine.

Functional or Anatomic Asplenia

CDC recommends people with functional or anatomic asplenia receive two vaccines for protection against meningococcal disease:

  • A meningococcal conjugate vaccine
  • A serogroup B meningococcal vaccine

Someone with anatomic asplenia does not have a spleen (for instance, if it was surgically removed). Someone with functional asplenia has a spleen but it doesn’t work the way that it should. People with sickle cell anemia have functional asplenia. The spleen is an important organ for fighting meningococcal infections because it helps produce antibodies and filter bacteria.

HIV Infection

CDC recommends people living with HIV receive a meningococcal conjugate vaccine. These vaccines provide protection against meningococcal disease caused by serogroups A, C, W, and Y. For HIV-infected people who get meningococcal disease, 4 in 5 cases (80%) are due to serogroups C, W, and Y. A low CD4 countexternal icon or high viral load increases risk of meningococcal disease for people living with HIV.

Learn more about meningococcal vaccine recommendations.

Page last reviewed: May 31, 2019