For many years, the ‘Green Book’ has recommended that when two live vaccines are required in the same individual, they should either be given on the same day, or separated by an interval of at least four weeks (based on early studies with measles and smallpox vaccines). The evidence to support this recommendation has been recently reviewed, and the JCVI has agreed that this guidance is not generalizable to all live vaccines. They concluded that intervals between vaccines should be based only upon specific evidence for any interference of those vaccines, and current immunisation guidance is being updated to reflect this change.
Specific recommendations are given concerning the combination of Yellow Fever and MMR (minimum 4-week interval) and Varicella (and zoster) vaccine and MMR (same day or minimum 4-week interval). The recommendation for all other live vaccines is that they can be administered at any time before or after each other.