on Hib Vaccine
questions & answers
Vaccine use, recommendations &
- What's the
difference between Haemophilus influenzae type b and
type b is a polysaccharide-
encapsulated bacteria that causes a variety of invasive syndromes,
such as meningitis, epiglottitis, and pneumonia. Influenza is a virus
that causes the disease influenza. Historical note: Haemophilus
influenzae was first isolated in 1889 from the sputum of a patient
who died of influenza, and the isolated organism (then called the
Pfeiffer bacillus) was assumed to have caused the patient's illness. Haemophilus
influenzae received its name in 1920, to acknowledge its
historical association with influenza. The viral cause of influenza
was not discovered until 1933.
use, recommendations and schedule related
- An infant
received 2 doses of Hib vaccine of a type that we do not stock in
our clinic. How do I finish the child's Hib series?
Hib conjugate vaccines licensed for
use in infants are interchangeable. The series may be completed with
any vaccine licensed for infants. The child should receive a total of
3 doses of any combination of Hib vaccines before the first birthday.
Any licensed conjugate vaccine may be used as the booster dose at
12-15 months of age if at least two months have elapsed since the
Children who are not up to date with
Hib vaccine present a challenge. They usually don't need a full series
of 3 or 4 doses of vaccine (depending on the brand used). A 12-month
old who received only one previous dose would need one dose of any
conjugate Hib vaccine now, and a second dose 2 months later. AAP's
2000 Red Book contains an excellent Hib vaccination table for
children who have fallen behind (p. 271).
- If a 13-month
old received Hib #1 at 8 months of age and Hib #2 today, does s/he
still need a booster in 2 months?
ACIP recommendations have not
addressed interrupted Hib vaccine schedules. The AAP (2000 AAP Red
Book, p. 271) recommends a child in this situation receive one
additional dose of any conjugate Hib vaccine 2 months after the dose
at 13 months of age.
- A child
started the Hib series at 2 months, received dose #2 at 6 months and
dose #3 at 14 months. Does this child need Hib #4?
The child received two doses of Hib
before the first birthday and a third dose shortly after the first
birthday. According to the 2000 Red Book (table 3.13, p. 271) the
child does not need a fourth dose.
- I've just
evaluated a 7-year old who does not have a record of receiving Hib
vaccine. Would a dose be indicated now?
ACIP does not recommend routine Hib
vaccination of healthy children 59 months of age or older, even if
they have no prior history of Hib vaccination.
- What is the
Hib schedule for children >15 months of age who have
fallen behind or are completely unvaccinated?
Children 15-59 months of age who have
an incomplete Hib vaccination schedule, including those who are
unvaccinated, should receive a single dose of any Hib conjugate
vaccine. Hib vaccine is not routinely recommended for persons 5 years
of age or older.
- Does anyone 5
years of age or older need to receive Hib vaccine?
There are few data on the efficacy of
Hib vaccine in persons 5 years of age or older. ACIP recommends
consideration of Hib vaccination for unvaccinated persons 5 years of
age and older with anatomic or functional asplenia, sickle-cell
anemia, or HIV infection (MMWR 1993;42[RR-4]:8; MMWR 1991;40[RR-12]:29).
A single dose of any licensed conjugate vaccine is probably sufficient
in most cases (using the dose recommended by the manufacturer for a
child). The 2000 AAP Red Book suggests 2 doses separated by 1-2
months for persons with HIV infection or IgG2 immune deficiency.
- If an infant
received one dose of Hib at 5 months, and another at 15 months, does
he/she need any more doses?
No. If a child receives a dose of Hib
vaccine at 15 months of age or older, he or she does not need any
further doses regardless of the number of doses received before 15
months of age.
- Since the
booster dose of Hib vaccine can be given at 12-15 months, is it
still necessary to "boost" two months later if the first
dose was given at 12-14 months?
If the child received a primary
series (2 or 3 doses) of Hib vaccine in the first year of life, then
the final (booster) dose of the series may be given as early as 12
months, provided at least 2 months have passed since the last dose. An
unvaccinated 12-14 month old child should receive one dose as a
primary series, and a booster dose 2 months later. Unvaccinated
children 15-59 months of age need only a single dose of any licensed
conjugate Hib vaccine.
- If a dose of
Hib vaccine was given by mistake to a 2-week-old, should further
doses of Hib vaccine be given?
Limited data suggest that Hib vaccine
given before 6 weeks of age may induce immunologic tolerance to Hib
antigen and reduce the response to subsequent doses. As a result, Hib
vaccine should not be given earlier than 6 weeks of age. However, if a
dose was administered before 6 weeks of age, it should not be counted
as part of the Hib series. A full series of 4 doses (Hibtiter, ActHib,
and Omnihib) or 3 doses (PedvaxHib and Comvax) should be started at 6–8
weeks of age as usual. No special protocol or testing is recommended
for children who received a dose of Hib vaccine before 6 weeks of age.
vaccine related questions:
- A 12-month-old
needs both Hib and hepatitis B vaccines today. Can I use Comvax
(Hib-Hep B combination vaccine from Merck), even if the child has
not previously received this combination product?
Yes. Comvax can be used when either
or both antigens are indicated and neither antigen is contraindicated.
Comvax would not be used after the fifth birthday because Hib vaccine
is not routinely recommended beyond this age. Comvax should also not
be used in infants less than 6 weeks of age.
- What should we
do if we discover a child who has received TriHIBit for the first,
second, or third dose of the DTaP-Hib series?
NIP and FDA recommend that any dose
of Hib vaccine given as TriHIBit before the first birthday not be
counted as part of the Hib series. The child should be revaccinated
with Hib vaccine appropriate for his/her age. The DTaP doses do NOT
need to be repeated. "Catch-up" schedules for Hib vaccine
can be found in the Hib ACIP statement (MMWR 1993;42,RR-13),
and in the AAP's 2000 Red Book.