Can the measles‑mumps‑rubella (MMR) vaccine and the combined hepatitis A and B vaccine (Twinrix) be administered on the same day?

Yes, MMR and Twinrix Can Be Administered on the Same Day

MMR (a live vaccine) and Twinrix (an inactivated combination hepatitis A/B vaccine) can and should be administered simultaneously on the same day at different anatomic sites. 1

Core Principle: Inactivated Vaccines Never Interfere

• All inactivated vaccines, including Twinrix (hepatitis A and B), can be given at any time before, with, or after live vaccines like MMR without concern for interference. 1
• The CDC explicitly states that inactivated vaccines—including hepatitis A, hepatitis B, and combination vaccines—can be administered simultaneously with live vaccines without affecting immunogenicity or safety. 1
• There is no immunologic reason to separate these two vaccines or to administer them in any particular sequence. 1

Administration Technique

• Administer each vaccine at separate anatomic sites (e.g., different arms) when giving them on the same day. 1
• Never mix the vaccines in the same syringe unless specifically FDA-licensed for mixing. 1
• Document both vaccines with dates and anatomic sites used. 1

Clinical Benefits of Same-Day Administration

• Simultaneous administration is particularly important when you anticipate the patient may not return for follow-up visits, which is common in adult vaccination. 1
• Approximately one-third of missed vaccination opportunities occur when vaccines are not given together during the same visit. 1
• Same-day administration reduces healthcare visits and increases overall vaccination completion rates. 1

Supporting Evidence

• Clinical trials demonstrate that concomitant administration of MMR with hepatitis vaccines shows comparable seroconversion rates (>93-100% for all antigens) with no significant safety concerns. 1
• Simultaneous administration of routine vaccines does not interfere with immune response when given at separate anatomic sites. 1
• Studies of MMR administered with other vaccines, including hepatitis B, have demonstrated acceptable immune responses to all antigens without increased adverse events. 2

Common Pitfall to Avoid

• Do not defer either vaccine to a separate visit. The only timing rule that matters here is that live vaccines (like MMR) must be separated by at least 4 weeks if not given simultaneously—but this does not apply to inactivated vaccines like Twinrix. 1, 2