Prevention of Perinatal HBV Infection
Transmission of perinatal HBV infection can be prevented
in approximately 95% of infants born to HBsAg-positive mothers
by early active and passive immunoprophylaxis of the infants,
ie, immunization and HBIG administration. Immunization subsequently
should be completed during the first 6 months of life. Hepatitis
B immunization only, initiated at or shortly after birth,
also is highly effective for preventing perinatal HBV infections.
Serologic Screening of Pregnant Women
Prenatal HBsAg testing of all pregnant women is recommended
to identify newborns who require immediate postexposure prophylaxis
and because selective testing fails to detect more than 50%
of women who are HBsAg-positive. Testing should be accomplished
during an early prenatal visit in each pregnancy and should
be repeated late in pregnancy for HBsAg-negative women who
are at high risk for HBV infection (eg, intravenous drug users
and those with intercurrent sexually transmitted diseases)
or who have had clinical hepatitis. Household contacts and
sexual partners of HBsAg-positive women identified through
prenatal screening should be immunized if susceptible or judged
likely to be susceptible to infection.
Management of Infants Born to HBsAg-Positive Women
Infants born to HBsAg-positive mothers, including preterm
infants, should receive the initial dose of hepatitis B vaccine
within 12 hours of birth (see Table 3.18, p 294, for appropriate
dosages), and HBIG (0.5 mL) should be given concurrently at
a different site. Subsequent doses of vaccine should be given
as recommended in Table 3.21 (p 300). For preterm infants
who weigh less than 2 kg at birth, the initial vaccine dose
should not be counted in the required 3-dose schedule, and
the subsequent 3 doses should be given in accordance with
schedule for immunization of preterm infants (see Preterm
Infants, p 54). Thus, a total of 4 doses are recommended in
this circumstance.
These infants should be tested serologically for anti-HBs
and HBsAg 1 to 3 months after completion of the immunization
series. Testing for HBsAg will identify infants who become
chronically infected and will aid in their long-term medical
management. Infants with anti-HBs concentrations of less than
10 mIU/mL and who are HBsAg-negative should receive 3 additional
doses of vaccine in a 0-, 1-, and 6-month schedule followed
by testing for anti-HBs 1 month after the third dose. Alternatively,
additional doses (1–3) of vaccine can be administered,
followed by testing for anti-HBs 1 month after each dose to
determine whether subsequent doses are needed.
Term Infants Born to Mothers Not Tested During Pregnancy
for HBsAg
Pregnant women whose HBsAg status is unknown at delivery
should undergo blood testing as soon as possible. While awaiting
results, the infant should receive the first hepatitis B vaccine
dose within 12 hours of birth in the dose recommended for
infants born to HBsAg-positive mothers (see Table 3.18, p
294). Because hepatitis B vaccine when given at birth is highly
effective for preventing perinatal infection in term infants,
the possible added value and the cost of HBIG do not warrant
its use when the mother’s HBsAg status is not known.
If the woman is found to be HBsAg-positive, the infant should
receive HBIG (0.5 mL) as soon as possible, but within 7 days
of birth, and be immunized subsequently as recommended (see
Table 3.18, p 294). If HBIG is unavailable, the infant still
should receive the 2 subsequent doses of hepatitis B vaccine
at 1 to 2 and 6 months of age (see Table 3.21, above). If
the mother is HBsAg-negative, hepatitis B immunization in
the dose and routine schedule for infants should be completed
(see Table 3.18, p 294).
Preterm Infants Born to Mothers Not Tested During
Pregnancy for HBsAg
The maternal HBsAg status should be determined as soon as
possible, and the infant should receive hepatitis B vaccine,
as recommended for term infants in this category. For preterm
infants who weigh less than 2 kg at birth, HBIG (0.5 mL) should
be given if the mother’s HBsAg status cannot be determined
within the initial 12 hours of birth because of the poor immunogenicity
of vaccine in these infants. The initial vaccine dose should
not be counted in the required 3 doses to complete the immunization
series. The subsequent 3 doses (for a total of 4 doses) are
given in accordance with the recommendations for the immunization
of preterm infants with birth weights less than 2 kg born
to HBsAg-negative women (see Preterm Infants, p 54). For preterm
infants of HBsAg-positive mothers, follow-up testing on completion
of immunization series is recommended (see Management of Infants
Born to HBsAg-Positive Women, p 298).
Breastfeeding. Breastfeeding of the infant by an HBsAg-positive
mother poses no additional risk for acquisition of HBV infection
by the infant (see Human Milk, p 98).
Household Contacts of Persons With Acute HBV Infection
Infants (ie, younger than 12 months of age) who have close
contact with primary care-givers with acute infection and
who have begun the immunization series should complete the
series on schedule. If immunization has not been initiated,
the infant should receive HBIG (0.5 mL), and hepatitis vaccine
should be given in accordance with the routinely recommended
3-dose schedule (see Preexposure Universal Immunization, p
295).
Prophylaxis with HBIG for other unimmunized household contacts
of persons with acute HBV infection is not indicated unless
they have identifiable blood exposure to the index patient,
such as by sharing of toothbrushes or razors. Such exposures
should be treated as in sexual exposures to a person with
acute HBV infection. All such persons, however, should be
immunized as soon as possible against hepatitis B because
of the possibility of future household exposures.
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