What are the contraindications for a child due for Measles (MR) vaccine who needs Rabies vaccine and Rabies Immunoglobulin (RIG)?

No Absolute Contraindications to Rabies Postexposure Prophylaxis in Children Due for MR Vaccine

There are no contraindications to administering rabies vaccine and RIG in a child who is due for MR vaccine—rabies postexposure prophylaxis should be given immediately as rabies is uniformly fatal, and the MR vaccine should be delayed until after completion of the rabies series. 1

Critical Priority: Rabies is 100% Fatal

• Rabies postexposure prophylaxis has no absolute contraindications when exposure has occurred, as the disease is nearly 100% fatal once clinical symptoms develop 1, 2
• The potential consequences of inadequately treated rabies exposure far outweigh any theoretical concerns about vaccine interactions 1

Timing Strategy for Both Vaccines

Administer rabies postexposure prophylaxis immediately, then delay MR vaccine:

• Begin rabies postexposure prophylaxis (both RIG and vaccine) as soon as possible after exposure 1
• The standard regimen is RIG 20 IU/kg on day 0 plus rabies vaccine on days 0,3,7,14, and 28 1, 2
• Delay the MR vaccine until after completion of the rabies vaccine series to avoid potential interference from RIG with the live viral vaccine response 3

Why MR Vaccine Should Be Delayed

• Immune globulins (including RIG) can interfere with the immune response to live viral vaccines like MMR/MR 1, 3
• The FDA label for M-M-R II specifically warns that immune globulins and blood products should not be given concurrently with the vaccine, as they may interfere with the expected immune response 3
• RIG provides passive antibodies that can suppress active antibody production to live viral vaccines for several weeks 1

Practical Implementation Algorithm

Step 1: Immediately administer rabies postexposure prophylaxis:

• Give RIG 20 IU/kg on day 0 (infiltrate around wounds if feasible, remainder IM at site distant from vaccine) 1, 2
• Give first rabies vaccine dose on day 0 in deltoid (or anterolateral thigh in young children) 1, 2
• Never administer RIG and vaccine in the same syringe or same anatomical site 1, 2

Step 2: Complete rabies vaccine series:

• Continue rabies vaccine on days 3,7,14, and 28 1, 2

Step 3: Administer MR vaccine after rabies series completion:

• Wait at least 3-4 weeks after RIG administration before giving MR vaccine to allow passive antibodies to clear 1
• This typically means the MR vaccine can be given approximately 1 month after completing the rabies series

Important Caveats

• Never use the gluteal area for rabies vaccine administration in children—this results in lower neutralizing antibody titers and inadequate immune response 1, 2
• For young children and infants, use the anterolateral thigh for rabies vaccine; for older children, use the deltoid 1, 2
• The slight delay in MR vaccine administration poses minimal risk compared to the absolute necessity of rabies prophylaxis 1
• If the child is immunocompromised, use a 5-dose rabies schedule (days 0,3,7,14,28) with RIG and check antibody titers 1, 2

Common Pitfall to Avoid

Do not withhold or delay rabies postexposure prophylaxis for any reason, including concerns about interactions with other vaccines—rabies is uniformly fatal and prophylaxis must not be interrupted 1, 4