The optimal recommended ages and intervals provide the best immune response. Every effort should be made to comply with the recommended ages and intervals. However in exceptional circumstances (such as imminent international travel, measles outbreak) it may be necessary to provide one or more vaccines at less than the optimal age or intervals.
Starting the primary schedule vaccines:
The optimal age is 2, 4 and 6 months.
The minimum age is 6 weeks minus 4 days – taking the 4 day rule into account
NOTE: Vaccines should only be given earlier in exceptional circumstances
Interval between the 1st and 2nd (2 and 4 month) visits
The optimal interval is 2 months
The minimum interval is 4 weeks
Interval between the 2nd and 3rd (4 and 6 month) visits
The optimal interval is 2 months.
The minimum interval is 8 weeks (and 16 weeks after 1st visit)
This accelerated schedule i.e. using minimum interval should only be used once in the schedule and not be used routinely. The remaining doses should be given at recommended intervals to ensure the best protection.
(See Table 2.2 Section 2.2.3 Chapter 2 Immunisation Guidelines for Ireland from the National Immunisation Advisory Committee)
