We mistakenly gave a patient the diluent for the two-vial formulation of Menveo (MenACWY-CRM) without adding it to the powdered vaccine. Since vaccine antigen is present in the diluent as well as in the powder, what should we do now?

The liquid vaccine component (the diluent) of Menveo contains the C, W-135, and Y serogroups, and the lyophilized vaccine component (the freeze-dried powder) contains serogroup A. Because the patient received only the diluent, he or she is not protected against invasive meningococcal disease caused by N. meningitidis serogroup A.

Invasive disease with N. meningitidis serogroup A is very rare in the United States, but is more common in some other countries. If the recipient (of the C-Y-135 “diluent” only) is certain not to travel outside the United States then the dose does not need to be repeated. However, if the recipient plans to travel outside the United States the dose should be repeated with correctly reconstituted Menveo, the one-vial formulation of Menveo that does not require reconstitution, or with a dose of another brand of MenACWY. There is no minimum interval between the incorrect dose and the repeat dose.