Do Tdap and MCV4 need to be spaced one month apart if not given simultaneously?
Certain experts recommend spacing these vaccines by a month if not given simultaneously. This is out of a theoretical safety concern of giving two vaccines containing diphtheria antigen (MCV4 contains diphtheria antigen) in close temporal proximity. However, ACIP feels that this theoretical safety concern does not warrant spacing, and recommends that these two inactivated vaccines can be administered simultaneously or non-simultaneously without a need for an interval between them.
