Can we vaccinate a 2-year-old boy with sickle cell disease against meningococcal disease if he has not completed a pneumococcal conjugate vaccine (PCV) series?

Possibly. If you are going to give him Menactra (MenACWY-D), you need to wait at least 4 weeks after he completes the PCV series before giving him the Menactra. There is no similar space consideration if Menveo (MenACWY-CRM) or MenQuadfi (MenACWY-TT) is used; these brands may be given simultaneously with PCV or at any interval before or after receipt of PCV.