| Explain
the various serologic tests for hepatitis B diagnosis
and what the results indicate? |
 |
| Table
1: Hepatitis B laboratory nomenclature |
| HBsAg: |
Hepatitis
B surface antigen is a marker of infectivity.
Its presence indicates either acute or chronic
HBV infection. |
| anti-HBs: |
Antibody
to hepatitis B surface antigen is a marker
of immunity. Its presence indicates an immune response
to HBV infection, an immune response to vaccination,
or the presence of passively acquired antibody.
(It is also known as HBsAb, but this
abbreviation is best avoided since it is often
confused with abbreviations such as HBsAg.) |
| anti-HBc
(total): |
Antibody
to hepatitis B core antigen is a nonspecific
marker of acute, chronic, or resolved HBV infection.
It is not a marker of vaccine-induced immunity.
It may be used in prevaccination testing to determine
previous exposure to HBV infection. (It is also
known as HBcAb, but this abbreviation
is best avoided since it is often confused with
other abbreviations.) |
| IgM
anti-HBc: |
IgM antibody
subclass of anti-HBc. Positivity indicates
recent infection with HBV (<6 mos). Its
presence indicates acute infection. |
| HBeAg: |
Hepatitis
B "e" antigen is a marker of a high
degree of HBV infectivity, and it correlates with
a high level of HBV replication. It is primarily
used to help determine the clinical management
of patients with chronic HBV infection. |
| Anti-HBe: |
Antibody
to hepatitis B "e" antigen may be
present in an infected or immune person. In persons
with chronic HBV infection, its presence suggests
a low viral titer and a low degree of infectivity. |
| HBV-DNA: |
HBV Deoxyribonucleic
acid is a marker of viral replication. It correlates
well with infectivity. It is used to assess and
monitor the treatment of patients with chronic
HBV infection. |
|
|
| Table 2: How do I
interpret some of the common hepatitis B panel results? |
|
| Tests |
Results |
Interpretation |
Vaccinate? |
HBsAg
anti-HBc
anti-HBs |
negative
negative
negative |
susceptible |
vaccinate
if indicated |
HBsAg
anti-HBc
anti-HBs |
negative
negative
positive with >10mIU/mL* |
immune
due to vaccination |
no
vaccination necessary |
HBsAg
anti-HBc
anti-HBs |
negative
positive
positive |
immune
due to natural infection |
no
vaccination necessary |
HBsAg
anti-HBc
IgM anti-HBc
anti-HBs |
positive
positive
positive
negative |
acutely
infected |
no
vaccination necessary |
HBsAg
anti-HBc
IgM anti-HBc
anti-HBs |
positive
positive
negative
negative |
chronically
infected |
no
vaccination necessary (may need treatment) |
HBsAg
anti-HBc
anti-HBs |
negative
positive
negative |
four
interpretations possible† |
use
clinical judgment |
| * |
Postvaccination testing, when it is recommended,
should be performed 1-2 months after the last dose of
vaccine. Infants born to HBsAg-positive mothers should
be tested for HBsAg and anti-HBs after completion of
at least 3 doses of a licensed hepatitis B vaccination
series, at age 9-18 months (generally at the next well
child visit). |
| †1. |
May be
recovering from acute HBV infection |
| 2. |
May be
distantly immune, but the test may not be sensitive
enough to detect a very low level of anti-HBs in
serum |
| 3. |
May be
susceptible with a false positive anti-HBc |
| 4. |
May be
chronically infected and have an undetectable level
of HBsAg present in the serum
|
|
|
|
|
|
|
|
| What are the signs and symptoms
of hepatitis B? |
|
| About 7 out of 10 adults with
acute hepatitis B have signs or symptoms when infected
with HBV. Children under age 5 years who become infected
rarely show any symptoms. Signs and symptoms of hepatitis
B might include nausea, lack of appetite, tiredness, muscle,
joint, or stomach pain, fever, diarrhea or vomiting, headache,
dark urine, light-colored stools, and yellowing of the
skin and whites of the eyes (jaundice). People who have
such signs or symptoms generally feel quite ill and might
need to be hospitalized. Every year, approximately 100-200
Americans die of fulminant (overwhelming acute infection)
hepatitis B. |
|
| How long does it take to
show signs of illness after a person becomes infected
with hepatitis B virus (HBV)? |
|
| The incubation period ranges
from 45 to 160 days (average 120.) |
|
| What is a VIS? |
|
| VIS is an acronym
for "vaccine information statement". The VIS must be provided
to recipients of hepatitis B vaccine. The National Childhood
Vaccine Injury Act of 1986 requires vaccine providers to give
a copy of the most current vaccine-specific VIS to all
recipients of vaccines that are included on the National
Vaccine Injury Compensation Program table maintained by the
Health Resources and Services Administration. The most current
VIS for hepatitis B vaccine is available at
www.cdc.gov/vaccines/pubs/vis/default.htm Statements in
languages other than English are available from IAC at
www.immunize.org/vis |
|
| What is the
proper temperature for storage of hepatitis B vaccine? |
|
| 35°-46° F (2°-8° C). Hepatitis
B vaccine should not be frozen. |
|
In adults, what
is the appropriate site for administration of hepatitis
B vaccine and what needle length and gauge should I
use? |
|
| The deltoid muscle is recommended
for routine intramuscular (IM) vaccination among adults.
The gluteus muscle should not be used as a site for administering
hepatitis B vaccine. The suggested needle size is 1"-2" depending
on the recipient's gender and weight (1" for females weighing
less than 70 kg; 1.5" for females weighing 70-100 kg; 1"-1.5" for
males weighing less than 120 kg; and 2" for males weighing
at least 120 kg and females more than 100 kg). A 22- to
25-gauge needle should be used. For optimal protection,
it is crucial that the vaccine be deposited intramuscularly,
not subcutaneously. |
|
How much protection
is provided for babies, teens, and adults after each
dose of hepatitis B vaccine? |
|
| Among a sample of
vaccinated persons, 56%-62% were positive for neutralizing
antibody 14 days after the first dose, and 94%-100% were
positive at one month. Other studies show that after one dose
of vaccine, protection ranges from 5%-35%; after two doses,
50%-90%; after three doses 85%-100%. The estimates vary a
great deal from study to study, even using the same vaccine
and the same dosage. However, considering the fact that the
vaccination series alone works very well after exposure, and
that the exposed person does not get even a second dose until
at least 1 MONTH after the exposure, most would agree that
there is good (but probably not long lasting) protection even
after a single dose for most persons. |
|
| How long is hepatitis
B vaccine protective? |
|
| Recent studies indicate that
immunologic memory remains intact for at least 23 years
and confers protection against clinical illness and chronic
HBV infection, even though anti-HBs levels might become
low or decline below detectable levels. |
|
| Is hepatitis B vaccine safe? |
|
| Yes. Hepatitis B vaccines have
been demonstrated to be safe when administered to infants,
children, adolescents, and adults. Since 1982, an estimated
70 million adolescents and adults and 50 million infants
and children in the United States have received at least
one dose of hepatitis B vaccine; a billion doses of hepatitis
B vaccine have been given worldwide. Vaccination causes
a sore arm occasionally, but serious reactions are very
rare. |
|
| Who should not receive
the vaccine? |
|
A serious allergic reaction
to a prior dose of hepatitis B vaccine or a vaccine component
is a contraindication to further doses of hepatitis B vaccine.
The recombinant vaccines that are licensed for use in the
United States are synthesized by Saccharomyces cerevisiae
(common baker's yeast), into which a plasmid containing
the gene for HBsAg has been inserted. Purified HBsAg is
obtained by lysing the yeast cells and separating HBsAg
from the yeast components by biochemical and biophysical
techniques. Persons allergic to yeast should not be vaccinated
with vaccines containing yeast.
|
Persons with a history of serious
adverse events, including anaphylaxis, after receipt of
hepatitis B vaccine should not receive additional doses.
As with other vaccines, vaccination of persons with moderate
or severe acute illness, with or without fever, should
be deferred until the illness improves. Vaccination is
not contraindicated in persons with a history of multiple
sclerosis, Guillain-Barrè syndrome, or autoimmune
diseases such as systemic lupus erythematosis or rheumatoid arthritis. |
|
| Where can I find a
CDC document that states that hepatitis B vaccine doesn't
have to be restarted if the series is interrupted? |
|
| The most recent discussion
of interrupted vaccine schedules can be found in the recommendations
of the ACIP Part 1: Immunization of Infants, Children,
and Adolescents published December 23, 2005. The document
states: |
|
|
| • |
|
When the
hepatitis B vaccine schedule is interrupted, the
vaccine series does not need to be restarted. |
| • |
|
If the series
is interrupted after the first dose, the second dose
should be given as soon as possible, and the second
and third doses should be separated by an interval
of at least 8 weeks. |
| • |
|
If only the third dose
is delayed, it should be administered as soon as
possible, after age 24 weeks (164 days). |
| • |
|
It is not necessary to
restart the vaccine series for infants switched from
one vaccine brand to another, including combination
vaccines. |
|
|
| If you want to test
and vaccinate your patient for hepatitis B on the same
day, does it matter if you test or vaccinate first? |
|
| Yes. You should draw the blood
first and then administer the first dose of vaccine, as
transient HBsAg-positivity has been found to occur after
a dose of hepatitis B vaccine. |
|
| How long should a person
wait to donate blood after a dose of hepatitis B vaccine? |
|
| It is advisable to wait one
month. Studies published in the last several years have
found that transient HBsAg positivity (lasting less than
21 days) can be detected in certain persons after vaccination. |
|
| If a patient is diagnosed
with acute hepatitis B and then resolves the infection,
can the patient ever get hepatitis B again? |
|
| Generally speaking, no. It
is possible, however, for a person to have two different
HBV infections, the second due to an HBV variant or a different
HBV subtype. |
|
| More of my patients
are getting tattoos and body piercings. Should they be
concerned about contracting a bloodborne infection like
HBV? |
|
| Yes. Tattooing and body piercing
have the potential to transmit bloodborne infections, including
HBV, hepatitis C virus (HCV), and human immunodeficiency
virus (HIV), if the person doing the tattoos or body piercing
does not use good infection control practices.
CDC recommends that instruments
intended to penetrate the skin be used once, then disposed
of or thoroughly cleaned and sterilized between clients.
Personal service workers who do tattooing or body piercing
should be educated about the transmission of bloodborne
pathogens and what precautions are needed to prevent transmission.
Persons considering getting
a tattoo or having a body part pierced should ask staff
at the establishment what procedures they use to prevent
the spread of bloodborne infections. They also might call
the local health department to find out what sterilization
procedures are required by law or ordinance for tattooing
and body piercing establishments.
IAC
has created a Web site with links to relevant articles
from medical journals and publications from national sources
such as CDC, HCV Advocate, the Alliance of Professional
Tattooists, and the Association of Professional Piercers.
Feel free to refer patients who are considering one or
both of these forms of body art to www.immunize.org/tattoos |
|
| What is the risk for
transmitting HBV by oral sex? |
|
| There are no specific data
on transmission of bloodborne viruses through oral-genital
sex. Saliva has not been associated with HBV transmission
unless biting has taken place. HBV is not spread by kissing,
hugging, sneezing, coughing, food or water, sharing eating
utensils or drinking glasses, or casual contact. |
|
| Can "French" kissing transmit
HBV? |
|
| While HBV has been found in
saliva, there are no data to suggest that kissing transmits
HBV; however, there have not been studies to specifically
look at "French" kissing. |
|
| My daughter was immunized
against hepatitis B about 4 years ago. She was recently
found "hepatitis B positive" by her gynecologist. Is
this possible? Could it be a false positive? |
|
| It is possible, but unlikely.
The HBsAg test has high sensitivity and specificity and
is quite trustworthy. She might have already been HBsAg
positive when she was vaccinated; therefore, the vaccine
would not have been effective. You should be assured that
the positive test was actually HBsAg and not another hepatitis
B test, such as anti-HBs (sometimes confusingly referred
to as HBsAB) or anti-HBc. A positive anti-HBs test is expected
after vaccination with hepatitis B vaccine, but not a positive
anti-HBc or HBsAg. If you are certain after careful checking
that the test and reported result are correct, you should
then make sure the laboratory that did the test repeated
the test in duplicate and then did neutralization. If your
daughter is ultimately determined to be truly HBsAg positive,
she should be referred to a liver disease specialist for
counseling and medical evaluation. |
|
| How stable is HBV in the
environment and what types of equipment cleaners are
viracidal against HBV? |
|
| Any high level
disinfectant that is tuberculocidal will kill HBV. It is important to note that
HBV is quite stable in the environment and remains viable
for 7 or more days on environmental surfaces at room temperature.
The virus is still capable of transmitting HBV despite
the absence of visible blood. |
|
|
| Prenatal,
perinatal and infant hepatitis B issues |
|
|
|
|
| What blood test should
be used to screen a pregnant woman to prevent perinatal
hepatitis B virus (HBV) infection? |
|
| Screening should be done with
the hepatitis B surface antigen (HBsAg) test only. This
blood test will tell whether a woman has current HBV infection
that can be transmitted to her infant. Ordering other blood
tests such as total antibody to hepatitis B core antigen
(total anti-HBc) and/or antibody to HBsAg (anti-HBs) are
not useful when screening to prevent perinatal HBV infections
and should not be included in screening pregnant women
for perinatal HBV infection. Total anti-HBc will be positive
in all HBsAg-positive persons and anti-HBs is rarely positive
in an HBsAg-positive person. Women who are found to be
HBsAg positive should then be referred for counseling and
medical evaluation that will include further testing. If
there is reason to suspect recently acquired HBV infection
in a pregnant woman, IgM class anti-HBc (IgM anti-HBc)
could be done to differentiate recently acquired HBV infection
from chronic HBV infection. IgM anti-HBc is the blood test
that is positive in recently acquired HBV infection. |
|
| Our laboratory screens
pregnant women with a hepatitis B panel. Is this correct? |
|
| No. A routine
hepatitis B panel for screening pregnant women is not advised,
nor is it necessary to determine current infection in a
pregnant woman. This practice has led to a number of women
being incorrectly labeled as HBsAg positive due to misinterpretation
of the results on the lab report. In reporting results,
some labs use the nomenclature "HBsAb" rather than the
more commonly used term "anti-HBs" to designate antibody
to HBsAg. Because the term "HBsAb" is only one character
different from "HBsAg," the lab report is subject to misinterpretation
and a number of "immune" women are incorrectly labeled
as "HBsAg positive". Their infants are given unnecessary
postexposure treatment with hepatitis B immune globulin
(HBIG) and the women experience unnecessary stress. |
|
| I understand there is an
excellent rapid test for HBsAg available for use in hospitals
or clinics. Could you comment on this? |
|
There are EIA-licensed
HBsAg assays that do have a rapid turn-around, but no rapid
assays as such; however, if you are unable to convince your
lab to use such rapid turn-around assays or if you cannot
switch labs to do so, you should do the following:
|
|
| • |
|
Order an
HBsAg assay stat. Verify when the test result will be
available and that it will be reported to the newborn
nursery ASAP. If the nursery doesn’t receive the report
at the expected time, call the lab for the result. |
| • |
|
Follow the
perinatal recommendations based on a mother with unknown
HBsAg status. Make sure you give the first dose of
single-antigen hepatitis B vaccine to infants of mothers
of unknown status within 12 hours of birth. For preterm
infants weighing less than 2 kg, give HBIG plus
hepatitis B vaccine within 12 hours of birth. Don’t wait
for the HBsAg test result before proceeding with
hepatitis B vaccination since ALL newborns are
recommended to receive hepatitis B vaccine at birth. |
| • |
|
If you get a positive
maternal HBsAg test result from the laboratory, give the
infant HBIG as soon as possible (no later than age 7
days) and complete the vaccine series according to the
schedule for infants born to HBsAg-positive mothers. If
the mother’s HBsAg test result is negative, follow the
routine vaccination recommendations for subsequent
doses. |
| • |
|
Communicate the infant’s
vaccination record (and HBIG record, if any) and the
mother’s HBsAg status to both the infant’s and mother’s
healthcare professionals. Follow-up case management is
critical for an infant whose mother’s HBsAg test result
was unknown or positive. |
| • |
|
Contact the perinatal
hepatitis B program at your local or state health
department immediately when your hospital identifies an
HBsAg-positive mother or when an infant is born to an
HBsAg-positive mother or a mother whose status is
unknown at the time. |
|
|
| Do women who have been
vaccinated previously against HBV infection still need
to be screened during pregnancy? |
|
| Yes. Women who have received
hepatitis B vaccine should still be screened for HBsAg
early with each pregnancy. Just because
a woman has been vaccinated does not mean she is HBsAg
negative. Since postvaccination testing is not performed
for most vaccinated persons, she could have been vaccinated
even though she was already HBsAg positive. |
|
| If a pregnant woman
has three documented doses of hepatitis B vaccine, why
does she need to be tested for HBsAg? |
|
| Just because she is vaccinated
does not assure that she is immune. Since routine prevaccination
testing is not recommended, one cannot be certain that
the patient did not have chronic HBV infection or was recently
infected with HBV at the time of vaccination. |
|
| Where can I obtain
a copy of the most recent recommendation of the Advisory
Committee on Immunization Practices (ACIP) for the
prevention of HBV infection in infants, children and
adolescents? |
|
| You can access the document
and the accompanying appendices at: www.cdc.gov/mmwr/PDF/rr/rr5416.pdf You
can also access the 2008 childhood immunization schedule
at:
www.cdc.gov/vaccines/recs/schedules/child-schedule.htm The
following table was excerpted from the December 2005
ACIP recommendations for infants, children, and, adolescents. |
|
|
|
|
|
| Review the
hepatitis B vaccination recommendations for preterm infants
who weigh less than 2kg (4.4 pounds), as well as for those
premature infants who weigh more. |
|
Preterm infants
weighing less than 2 kg (4.4 lb) at birth have a decreased
response to hepatitis B vaccine administered before age 1
month. (By age 1 month, medically stable preterm infants,
regardless of initial birth weight or gestational age, have an
immunologic response to hepatitis B vaccination that is
comparable to that of full-term infants.) For preterm infants
weighing less than 2 kg at birth:
|
| • |
|
If maternal
HBsAg status is positive: Give hepatitis B immune
globulin (HBIG) plus hepatitis B vaccine within 12 hours
of birth. Give 3 additional hepatitis B vaccine doses
(with single-antigen vaccine at ages 1, 2–3, and 6
months, or hepatitis B-containing combination vaccine at
ages 2, 4, and 6 months [Pediarix®] or 2, 4, and 12–15
months [Comvax®]. Test for HBsAg and antibody to HBsAg
1–2 months after completion of at least 3 doses of a
licensed hepatitis B vaccine series (i.e., at age 9–18
months, generally at the next well-child visit). Testing
should not be performed before age 9 months nor within 4
weeks of the most recent vaccine dose. |
| • |
|
If
maternal HBsAg status is unknown: Give HBIG plus hepatitis B
vaccine within 12 hours of birth. Be sure to test the
mother’s blood for HBsAg. Give 3 additional hepatitis B
vaccine doses (with single-antigen vaccine at ages 1,
2–3, and 6 months, or hepatitis B-containing combination
vaccine at ages 2, 4, and 6 months [Pediarix] or 2, 4,
and 12–15 months [Comvax]. |
| • |
|
If the maternal HBsAg
status is negative: If you are certain that appropriate
testing was done and the mother’s test result is
negative, delay the first dose of hepatitis B vaccine
until age 1 month or hospital discharge. Complete the
vaccine series per the recommended schedule. |
|
For preterm infants weighing 2
kg or more at birth. For these preterm infants, follow the
recommendations for full-term infants including the birth dose
for all, keeping in mind the special needs of newborns whose
mother’s HBsAg status is positive or unknown. |
| |
| What should delivery hospitals
know to prevent perinatal HBV transmission? |
|
| The most important
thing you can do is to ensure that all newborns receive the
needed protection of hepatitis B vaccine and to make sure your
hospital has policies and procedures in alignment with the
recommendations of CDC, AAP, and AAFP, which include
establishing standing orders for administration of hepatitis B
vaccine as part of routine medical care of all medically
stable infants weighing 2 kg (4.4 lb) or more. By putting this
policy into place, you are ensuring that every newborn will
receive the birth dose prior to hospital discharge (unless an
order is written in the infant’s chart by the healthcare
provider to NOT give it). According to the official
recommendations, an order to delay the birth dose until after
hospital discharge may be done, on a case-by-case basis, and
only in rare circumstances. Guidelines for implementing birth
dose policies are found in the official CDC recommendations on
hepatitis B prevention in children available at
www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a1.htm?s_cid=rr5416a1_e
(HTML version). You can also use the labor and delivery and
nursery guidelines from the Immunization Action Coalition (IAC)
available at
www.immunize.org/catg.d/p2130.pdf |
|
| Delivery hospitals
should enroll in the federally funded Vaccines for Children (VFC)
program to obtain free hepatitis B vaccine for administration
of the birth dose to newborns that are eligible (i.e.,
Medicaid eligible, American Indian or Alaska Native,
underinsured, or uninsured). The VFC information is available
at:
www.cdc.gov/vaccines/programs/vfc/default.htm |
|
| Why is it recommended
to give hepatitis B vaccine to infants when the greatest
numbers of cases occur in young adults? |
|
| Prior to the implementation
of routine infant hepatitis B immunization in the United
States, about 15,950 (range: 8,980-32,190) children under
age 10 years were infected with HBV annually. Two-thirds
of these children, who became infected with HBV during
childhood, did not have HBV-infected mothers. Perinatal
prevention programs that identify HBsAg-positive mothers
and that provide immunoprophylaxis to their infants would
not have prevented these infections. |
|
| In contrast to other vaccine-preventable
diseases of childhood, HBV infection in infants and young
children is usually asymptomatic. Thus, the small number
of reported cases of hepatitis B among children represents
the tip of the iceberg of all HBV infections in children.
For every child with symptoms of hepatitis B, there are
at least 100 children with asymptomatic HBV infection. |
|
| The birth dose that is recommended
routinely provides effective postexposure immunoprophylaxis
to prevent transmission in the perinatal period and early
infancy. Some of the reasons for this important recommendation
are as follows: |
|
| • |
|
HBsAg testing
of mothers does not identify all newborns that require
postexposure immunoprophylaxis. Errors are sometimes
made in ordering tests, reporting test results, and
omitting vaccination of infants of known HBsAg-positive
mothers. The birth dose serves as a "safety
net," preventing perinatal infection among infants
born to all mothers who are HBsAg positive and assures
protection for all infants. |
| • |
|
The birth
dose provides early protection to infants at risk
for infection after the perinatal period. Although
infections in young children represented less than
10% of all HBV infections before implementation of
routine childhood hepatitis B vaccination, childhood
infections resulted in an estimated 30%–40% of chronic
HBV infections among persons who acquired their infections
in the U.S. Many of these chronic infections would
not have been prevented by a selective program of
identification and immunization of only those infants
born to HBsAg-positive mothers. Based on the age-specific
risk of chronic HBV infection, it is estimated that
about one-third of the 1.25 million Americans with
chronic HBV infection acquired their infection as
infants or young children. Children who become chronically
infected have a 25% risk of dying prematurely from
liver cancer or cirrhosis.
www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a1.htm?s_cid=rr5416a1_e |
|
|
| I'm a pediatrician
and support the use of the birth dose of hepatitis B
vaccine. I give it routinely, but a few parents object.
In my practice, almost 100% of my infant patients' mothers
are tested for HBsAg and almost all are reported to be
negative. Could you tell me how many cases of HBV infection
occur each year in babies who are born to documented
HBsAg-negative mothers? |
|
| Because infants born to HBsAg-negative
mothers are usually not tested for HBV infection, and because
virtually all HBV infections occurring among infants are
asymptomatic, it is not possible to quantify the number
of HBV-infected infants born to mothers believed to be
HBsAg negative. However, we know that many unvaccinated
newborns have been left needlessly at risk of infection
because of errors in maternal hepatitis B testing and reporting.
In two surveys conducted by IAC covering the period from
July 1999 to October 2002, state and local hepatitis B
coordinators reported more than 500 medical errors discovered
through their perinatal hepatitis B prevention programs.
Many of these errors involved misinterpreting or mistranscribing
hepatitis screening test results, or ordering the wrong
hepatitis B screening test. Such errors can lead to a mother
being documented as HBsAg negative, when she is actually
HBsAg positive. Use of the hepatitis B vaccine birth dose
safeguards against these maternal hepatitis B testing and
reporting errors and also prevents early childhood HBV
infections. The birth dose also protects the infants of
women who become HBV infected after having been screened
in early pregnancy and not tested later in pregnancy. |
|
| Preventing possible HBV transmission
in early childhood is also a major issue. Seroprevalence
data from the National Health and Nutrition Examination
Surveys have provided estimates of the number of early
HBV infections. Based on these data, approximately 16,000
children under 10 years of age were infected with HBV beyond
the postnatal period each year before routine infant vaccination
was recommended in 1991 (Armstrong GL, Mast EE, Wojczynski
M, Margolis HS. Childhood hepatitis B virus infections
in the United States before hepatitis B immunization. Ped.
200l;108(5):1123-28). Although these infections represented
only 5%-10% of all persons with chronic HBV infection in
the United States at that time, it is estimated that 18%
of all persons with chronic HBV infection acquired their
infections postnatally during early childhood. In some
populations, childhood transmission was more important
than perinatal transmission as a cause of chronic HBV infection
before infant hepatitis B immunization was widely implemented.
For example, in studies conducted among children born in
the United States with Southeast Asian refugee parentage
during the 1980s, approximately 60% of chronic HBV infections
in young children were among children born to HBsAg-negative
mothers. Since implementation of routine childhood immunization,
an estimated 6,800 perinatal HBV infections have been prevented
in the United States annually. |
|
| Does a birth dose of
vaccine increase the risk of elevated temperature and
subsequent microbiologic evaluations? |
|
| No. Administration of hepatitis
B vaccine soon after birth has not been associated with
an increased rate of elevated temperatures or subsequent
evaluations for possible sepsis in the first 21 days of
life. |
|
| Children born in the
United States continue to be infected with HBV. What
more can be done? |
|
| It is as simple as following
standard of care. All women should be screened for HBsAg
early with each pregnancy independent
of the woman's hepatitis B vaccination status. Testing
should be repeated if the woman has risk factors for HBV
infection, such as recent or current injection drug use
(IDU), having had more than one sex partner in the previous
6 months, an HBsAg-positive sex partner, or evaluation
or treatment for a sexually transmitted disease (STD).
If a risk factor is identified during pregnancy, the woman
should be started on the hepatitis B vaccine series right
away. Pregnancy is not a contraindication
to receiving hepatitis B vaccine. |
|
| The ACIP recommends that routine
infant hepatitis B vaccination should begin at birth. On
a case-by-case basis and only in rare circumstances, the
first dose may be delayed until after hospital discharge
for an infant who weighs at least 2 kg and whose mother
is HBsAg negative. A physician's order to withhold the
birth dose and a copy of the original laboratory report
indicating that the mother was HBsAg negative during this
pregnancy should be placed on the infant's medical record. |
|
| To prevent HBV transmission
among children at greatest risk for HBV infection, the
ACIP also recommends that prenatal care providers, delivery
hospitals, and health departments implement policies and
procedures to identify and manage children born to HBV-infected
mothers and mothers with unknown HBV infection status.
The birth dose acts as a safety net if screening for HBsAg
is not performed, misordered, misinterpreted, or mistranscribed.
The birth dose also provides early protection to infants
at risk for infection after the perinatal period. In addition,
studies have shown that infants who receive the birth dose
of hepatitis B vaccine are more likely to complete their
childhood immunizations on schedule. |
|
| Our hospital is dragging
its feet on reinstitution of a policy for the hepatitis
B vaccine birth dose. How can I help convince them that
this is the standard of care? |
|
| Administration of a birth dose
of hepatitis B vaccine is required for effective postexposure
immunoprophylaxis to prevent perinatal HBV infection. Although
infants who require postexposure immunoprophylaxis should
be identified by maternal HBsAg testing, administering
a birth dose to infants, even without HBIG, serves as a "safety
net" to prevent perinatal infection among infants born
to HBsAg-positive mothers who are not identified, because
of errors in maternal HBsAg testing or failure in reporting of
test results. |
|
| The birth dose provides early
protection to infants at risk for infection after the perinatal
period. Although infections in young children represented
less than 10% of all HBV infections before implementation
of routine childhood hepatitis B vaccination, childhood
infections resulted in an estimated 30%-40% of the chronic
HBV infections among persons who acquired their infections
in the United States. Many of these chronic infections
would not have been prevented by a selective program of
identification and immunization of only infants born to
HBsAg-positive mothers. |
|
| ACIP recommends that all newborns
be vaccinated in the hospital prior to hospital discharge.
AAP and AAFP have also endorsed these recommendations.
ACIP recommends the following with regard to administering
the birth dose: |
|
| • |
|
All delivery
hospitals should implement standing orders for administration
of hepatitis B vaccine as part of routine medical
care of all medically stable infants weighing 2 kg
(4.4 lb) or more at birth. |
| • |
|
All medically stable
infants weighing 2 kg or more at birth and born to
HBsAg-negative mothers should receive the first dose
of vaccine (single-antigen only) before hospital
discharge. |
| • |
|
On a case-by-case
basis and only in rare circumstances, the first dose
may be delayed until after hospital discharge for
an infant who weighs 2 kg or more and whose mother
is HBsAg negative. In this case, a physician’s order
not to give the birth dose must be written, and a
copy of the original HBsAg-negative laboratory report
during this pregnancy should be placed in the infant’s
medical record. The official ACIP recommendations
for hepatitis B vaccination of children are available
at
www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a1.htm?s_cid=rr5416a1_e.pdf |
|
|
| Administration of a birth dose
has been associated with higher rates of on-time completion
of the hepatitis B vaccine series. In certain populations,
the birth dose has been associated with improved completion
rates for all other infant vaccines. |
|
| For more information, go to www.immunize.org/birthdose, and
www.cdc.gov/vaccines/recs/schedules/child-schedule.htm |
|
| In the newborn nursery,
I had a parent insist on Recombivax HB® for
their infant because Engerix B®'s
package insert reports that vaccine contains a "trace" amount
of thimerosal. Does this have any clinical significance? |
|
| No. The pediatric/adolescent
formulation of Engerix B contains less
than 1 microgram of thimerosal per 0.5cc dose. (One microgram
is one millionth of a gram.) This represents a greater
than 96% reduction from the 12.5 micrograms in the previous
version of the vaccine and is an amount of thimerosal that
is considered clinically insignificant. |
|
| If a mother's HBsAg
test result is not available at the time of birth, how
should the infant be managed? |
|
| • |
|
Women admitted
for delivery without documentation of HBsAg test
results should have blood drawn and tested as soon
as possible after admission. |
| • |
|
While test results are
pending, all infants born to women without documentation
of HBsAg test results should receive the first dose
of single-antigen hepatitis B vaccine (without HBIG)
by 12 hours of birth. |
| |
|
| • |
|
If
the mother is determined to be HBsAg positive,
her infant should receive HBIG as soon as possible
but no later than age 7 days, and the vaccine
series should be completed according to a recommended
schedule for infants born to HBsAg-positive
mothers. |
| |
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