Vaxelis Catch-Up Vaccination at 5 Months
Yes, you can administer the missed second dose of Vaxelis today to a 5-month-old infant and return in 4 weeks for the third dose, as this follows the minimum interval requirements and catch-up vaccination principles.
Minimum Interval Requirements for Vaxelis
The minimum interval between any two doses of Vaxelis is 4 weeks, which makes your proposed schedule appropriate 1. Specifically:
- Minimum interval between doses 1 and 2: 4 weeks 1
- Minimum interval between doses 2 and 3: 4 weeks 1
- Minimum age for dose 2: 10 weeks 1
- Minimum age for dose 3: 24 weeks (6 months) 1
Critical Timing Consideration for Dose 3
The third dose of Vaxelis should not be given before 24 weeks of age due to the hepatitis B component requiring adequate immune maturation 1. At 5 months (approximately 20-22 weeks), if you give dose 2 today and return in 4 weeks, the child will be approximately 24-26 weeks old, which meets this requirement 1.
If the third dose is inadvertently given before 24 weeks of age, an additional dose of hepatitis B vaccine must be given at age ≥24 weeks to complete the hepatitis B series 1.
General Catch-Up Principles
There is no need to restart a vaccine series regardless of the time that has elapsed between doses 1. The fundamental principle is to continue where you left off and maintain minimum intervals 1.
For catch-up vaccination:
- Doses should not be administered at intervals less than the minimum intervals 1
- Doses administered ≥5 days before the minimum interval should not be counted as valid and must be repeated 1
- Doses administered <4 days before the minimum interval can be counted as valid 1
Recommended Schedule for This Patient
- Today (at 5 months): Administer the second dose of Vaxelis
- In 4 weeks (at approximately 6 months): Administer the third dose of Vaxelis
This schedule ensures:
- The minimum 4-week interval between doses 2 and 3 is maintained 1
- The third dose is given at or after 24 weeks of age as required 1
- The child completes the primary series without unnecessary delay 1
Important Caveats
Vaxelis is only indicated for the primary 3-dose series at 2,4, and 6 months and should not be used for booster doses 1. If inadvertently given for a booster dose, it does not need to be repeated if proper spacing was maintained 1.
Vaxelis requires a 3-dose primary series for the Hib component, unlike some monovalent PRP-OMP Hib vaccines that only require 2 primary doses 1. All three doses must be completed for adequate Hib protection 1.
The maximum age for any dose of Vaxelis is 4 years, 364 days (do not administer on or after the fifth birthday) 1.