In this study, the investigators will evaluate the immunogenicity of a quadrivalent conjugate meningococcal vaccine in healthy, plateletpheresis donors.

This will be an open-label prospective vaccine response study evaluating one dose of MenACWY-D in plateletpheresis donors at the Brigham and Women's Hospital (BWH). Potential participants will be divided into three groups according to the number of plateletpheresis within 365 days of enrollment (including the day of enrollment): 1-2 sessions group (considered as the control group), 3-19 sessions group, 20-24 sessions group and randomly sampled from in allocation proportions of 0.45, 0.10, and 0.45, respectively; justification for this approach is provided in the Statistical Analysis section. MenACWY-D vaccine will be administered to each patient. Pre- and post-vaccination blood will be collected to assess immunogenicity, likely using serum bactericidal antibody (SBA) against Neisseria meningitidis for each serogroup. Immunogenicity will be primarily evaluated by seroresponse such as a fourfold increase of SBA titers between pre- and post-vaccination.

Inclusion Criteria:

• Male or female aged 18 years old or older
• Meet the standard requirements to donate platelets
• Have had at least one plateletpheresis in the prior 365 days (including the day of enrollment)

Exclusion Criteria:

• Participants who donated platelets in any other medical center in the previous 365 days
• Severe allergic reaction to a previous meningococcal vaccine or to any component of MenACYW-D
• History of Guillain-Barré syndrome

Deidentified data will be made available upon request to the principal investigator following the publication of the primary manuscript.