Delay guide · Hib
Delaying the Hib vaccine
Hib: 4 doses on the on-time schedule and as few as 1 dose when started later; healthy children who reach 5 years generally do not need it (CDC). Delaying lengthens the time your child is unprotected against Hib (a cause of meningitis & epiglottitis). Hib disease mainly affects children younger than 5.
Key takeaways
- Can it be delayed? Yes. A later start can mean fewer doses, with a longer unprotected window.
- On the on-time schedule Hib is 4 doses. Under the CDC catch-up rules a healthy child who starts later needs as few as 1, and from 5 years of age generally none.
- Hib disease mainly affects children younger than 5.
- In our state data, none of the 51 jurisdictions (50 states and DC) lists Hib as a kindergarten requirement. Some may require it for childcare, and rules change, so check your state page.
Can the Hib vaccine be delayed?
Yes. A later start can mean fewer doses, with a longer unprotected window.
Delaying means a longer stretch during which your child has less protection than the CDC's on-time schedule would give, and often more visits overall. It does not make the vaccine less effective once the series is complete. Whether that trade-off suits your child is a decision for you and your child's healthcare practitioner.
What changes if you start later?
On the on-time schedule Hib is 4 doses. Under the CDC catch-up rules a healthy child who starts later needs as few as 1, and from 5 years of age generally none.
- starting at 15–59 months needs only a SINGLE dose.
- Healthy children who reach age 5 (60 months) do not need Hib at all.
- Most protective window for Hib disease is infancy; delaying trades fewer shots for later protection.
Healthy children who reach 5 years of age generally do not need Hib. Children with certain medical conditions are treated differently.
Compare all vaccines or read how delayed schedules work.
What are the risks of waiting?
Hib disease mainly affects children younger than 5.
- Hib (Haemophilus influenzae type b) can cause meningitis, bloodstream infection, pneumonia and epiglottitis. The CDC says serious infections can result in long-term health problems and death.
- The CDC says Hib primarily affects children younger than 5 and recommends the vaccine for all children in that age group. That is why the dose count falls the later a healthy child starts, and why the vaccine is generally not needed from age 5.
Sources: About Haemophilus influenzae disease .
What are the minimum ages and intervals for Hib?
A minimum age and a minimum interval are the earliest a dose counts. The CDC allows a 4-day grace period. Waiting longer than the minimum is always allowed.
| First dose at | Total doses | Minimum age and gap, by dose |
|---|---|---|
| 7 months to 11 months | 3 |
|
| 12 months to 14 months | 2 |
|
| 15 months to 59 months | 1 |
|
How do you catch up on Hib?
The CDC says a vaccine series does not need to be restarted, however much time has passed between doses; doses already given still count. See the catch-up schedule guide.
- The number of doses depends on age at the first dose: 3 if started at 7 to 11 months, 2 at 12 to 14 months, and 1 at 15 to 59 months.
- Some brands have slightly different schedules; your practitioner will confirm which applies.
Is the Hib vaccine required for school?
In our state data, none of the 51 jurisdictions (50 states and DC) lists Hib as a kindergarten requirement. Some may require it for childcare, and rules change, so check your state page.
Look up your state. Many states also allow provisional enrollment while a series is in progress.
Frequently asked questions
Can the Hib vaccine be delayed?
Yes. A later start can mean fewer doses, with a longer unprotected window. On the on-time schedule Hib is 4 doses. Under the CDC catch-up rules a healthy child who starts later needs as few as 1, and from 5 years of age generally none.
What are the risks of delaying the Hib vaccine?
Hib (Haemophilus influenzae type b) can cause meningitis, bloodstream infection, pneumonia and epiglottitis. The CDC says serious infections can result in long-term health problems and death. The CDC says Hib primarily affects children younger than 5 and recommends the vaccine for all children in that age group. That is why the dose count falls the later a healthy child starts, and why the vaccine is generally not needed from age 5.
What is the minimum age for the Hib vaccine?
The first dose of Hib can be given from 7 months. Later doses have their own minimum ages and minimum intervals after the previous dose, shown in the table on this page. The CDC counts a dose given up to 4 days before a minimum age or interval.
Is the Hib vaccine required for school?
In our state data, none of the 51 jurisdictions (50 states and DC) lists Hib as a kindergarten requirement. Some may require it for childcare, and rules change, so check your state page.
See how Hib fits into a full plan
The free planner applies these rules for you and shows what fits before a school deadline. Review the result with your child's healthcare practitioner.
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