Question 1

Should I restart a vaccine series if a dose was given late?

Accepted Answer

No. Interruptions in the immunisation schedule should not require restarting any series. Simply give the next due dose according to the catch-up schedule, maintaining the recommended minimum intervals. The immune system still produces an adequate anamnestic response.

Question 2

Can multiple vaccines be given at the same catch-up visit?

Accepted Answer

Yes — WHO and all major programmes support simultaneous administration of multiple routine vaccines at the same visit as long as they are given at different anatomic sites. This accelerates catch-up without safety concerns. Only live viral vaccines (MMR, varicella, yellow fever) must be given on the same day or separated by ≥28 days if not simultaneous.

Question 3

How does the tool handle vaccines with upper age limits?

Accepted Answer

Rotavirus vaccine has strict upper age limits (first dose by 15 weeks, last dose by 32–36 weeks depending on programme). PCV is not recommended after 59 months. The tool enforces these limits by not scheduling doses if the child's current age exceeds the maximum eligible age for that vaccine.