What is the recommended interval before receiving another vaccine, including differences for live‑attenuated and inactivated vaccines?

Vaccine Interval Recommendations

Inactivated vaccines can be administered at any time before or after other inactivated or live vaccines without any required waiting period, while live-virus vaccines given on different days should be separated by at least 30 days unless specifically exempted. 1

Inactivated Vaccines

No waiting period is required between inactivated vaccines. Inactivated vaccines generally do not interfere with the immune response to other inactivated vaccines or to live vaccines (except in rare instances like yellow fever and cholera vaccines). 1

• An inactivated vaccine can be administered either simultaneously or at any interval before or after a different inactivated vaccine or live vaccine. 1
• When given simultaneously, injectable vaccines should be administered at separate anatomical sites. 2, 3
• There is no medical justification for delaying inactivated vaccines after any other vaccine type. 2

Live-Attenuated Vaccines

Live-virus vaccines administered on different days must be separated by at least 30 days to prevent potential immune interference. 1

• The theoretical concern is that one live-virus vaccine might impair the immune response to another if administered within 30 days, though no evidence exists for currently available vaccines to support this concern. 1
• Critical exceptions exist: OPV and MMR vaccines can be administered at any time before, with, or after each other without restriction. 1
• Live attenuated influenza vaccine (LAIV) may be administered simultaneously with oral Ty21a typhoid vaccine or at any interval. 2
• If LAIV is given with other parenteral live vaccines (excluding typhoid), they should either be administered on the same day or separated by at least 4 weeks. 2

Special Considerations with Immune Globulin

Immune globulin products can significantly interfere with live vaccine responses and require specific timing intervals. 1

Live Vaccines After Immune Globulin:

• High doses of immune globulin can inhibit the immune response to measles vaccine for more than 3 months. 1
• MMR and its individual component vaccines should not be administered before the recommended interval after immune globulin receipt (specific intervals vary by immune globulin dose and product). 1
• Exception: OPV and yellow fever vaccines can be administered at any time before, with, or after immune globulin administration. 1

Immune Globulin After Live Vaccines:

• If immune globulin is given less than 14 days after MMR or its component vaccines, vaccination should be repeated after the recommended interval unless serologic testing confirms antibody production. 1
• Vaccine virus replication and immunity stimulation typically occur 1-2 weeks after vaccination. 1

Inactivated Vaccines and Immune Globulin:

• Immune globulin preparations interact minimally with inactivated vaccines and toxoids. 1
• Inactivated vaccines and toxoids can be administered simultaneously with or at any interval before or after immune globulin receipt without substantially impairing antibody response. 1

Tuberculin Testing Considerations

Live-virus vaccines can interfere with tuberculin test responses. 1

• Tuberculin testing should be done either on the same day that live-virus vaccines are administered or 4-6 weeks later. 1

Common Pitfalls to Avoid

• Do not unnecessarily delay inactivated vaccines: There is no medical reason to separate inactivated vaccines from any other vaccine type, and delaying increases the risk of missing the optimal protection window. 2
• Do not apply the 30-day rule to inactivated vaccines: The spacing requirement applies only to live-virus vaccines given on different days. 1
• Do not forget the MMR/OPV exception: These live vaccines can be given together or at any interval despite both being live-attenuated. 1
• Do not mix vaccines in the same syringe: Injectable vaccines given concomitantly should never be mixed unless specifically FDA-approved for mixing. 3
• Do not overlook immune globulin history: Always assess recent immune globulin administration before giving live vaccines, as this can necessitate delays of several months. 1