Excerpt from Sexually Transmitted Diseases Treatment Guidelines, 2006
http://www.medscape.com/viewarticle/543426_16
Hepatitis B
Hepatitis B is caused by infection with HBV. The incubation period from the
time of exposure to onset of symptoms is 6 weeks to 6 months. HBV is found
in highest concentrations in blood and in lower concentrations in other body
fluids (e.g., semen, vaginal secretions, and wound exudates). HBV infection
can be self-limited or chronic. In adults, only approximately half of newly
acquired HBV infections are symptomatic, and approximately 1% of reported
cases result in acute liver failure and death. Risk for chronic infection is
inversely related to age at infection: approximately 90% of infected infants
and 30% of infected children aged <5 years become chronically infected,
compared with 2%--6% of adults. Among persons with chronic HBV infection,
the risk for premature death from cirrhosis or hepatocellular carcinoma
(HCC) is 15%--25%.
HBV is efficiently transmitted by percutaneous or mucous membrane exposure
to infectious blood or body fluids that contain blood. The primary risk
factors that have been associated with infection among adolescents and
adults are unprotected sex with an infected partner, unprotected sex with
more than one partner, MSM, history of other STDs, and illegal
injecting-drug use.
CDC's national strategy to eliminate transmission of HBV infection includes
1) prevention of perinatal infection through routine screening of all
pregnant women for HBsAg and immunoprophylaxis of infants born to
HBsAg-positive mothers and infants born to mothers with unknown HBsAg
status, 2) routine infant vaccination, 3) vaccination of previously
unvaccinated children and adolescents through age 18 years, and 4)
vaccination of previously unvaccinated adults at increased risk for
infection.[2,4] High vaccination coverage rates, with subsequent declines in
acute hepatitis B incidence, have been achieved among infants and
adolescents.[2,203,204] In contrast, vaccination coverage among the majority
of high-risk adult groups (e.g., persons with more than one sex partner in
the previous 6 months, MSM, and IDUs) have remained low, and the majority of
new infections occur in these high-risk groups.[4,205--207] STD clinics and
other settings that provide services targeted to high-risk adults are ideal
sites in which to provide hepatitis B vaccination to adults at risk for HBV
infection. All unvaccinated adults seeking services in these settings should
be assumed to be at risk for hepatitis B and should receive hepatitis B
vaccination.
Diagnosis
Diagnosis of acute or chronic HBV infection requires serologic testing (
Table 4 ). HBsAg is present in both acute and chronic infection. The
presence of IgM antibody to hepatitis B core antigen (IgM anti-HBc) is
diagnostic of acute or recently acquired HBV infection. Antibody to HBsAg
(anti-HBs) is produced after a resolved infection and is the only HBV
antibody marker present after immunization. The presence of HBsAg and total
anti-HBc, with a negative test for IgM anti-HBc, indicates chronic HBV
infection. The presence of anti-HBc alone might indicate a false-positive
result or acute, resolved, or chronic infection.
Treatment
No specific therapy is available for persons with acute hepatitis B;
treatment is supportive. Persons with chronic HBV infection should be
referred for evaluation to a physician experienced in the management of CLD.
Therapeutic agents approved by FDA for treatment of chronic hepatitis B can
achieve sustained suppression of HBV replication and remission of liver
disease in some persons. In addition, patients with chronic hepatitis B
might benefit from screening to detect HCC at an early stage.
Prevention
Two products have been approved for hepatitis B prevention: hepatitis B
immune globulin (HBIG) and hepatitis B vaccine. HBIG provides temporary
(i.e., 3--6 months) protection from HBV infection and is typically used as
PEP either as an adjunct to hepatitis B vaccination in previously
unvaccinated persons or alone in persons who have not responded to
vaccination. HBIG is prepared from plasma known to contain high
concentrations of anti-HBs. The recommended dose of HBIG is 0.06 mL/kg.
Hepatitis B vaccine contains HBsAg produced in yeast by recombinant DNA
technology and provides protection from HBV infection when used for both
preexposure immunization and PEP. The two available monovalent hepatitis B
vaccines for use in adolescents and adults are Recombivax HB® (Merck and
Co., Inc., Whitehouse Station, New Jersey) and Engerix-B® (GlaxoSmithKline
Biologicals, Pittsburgh, Pennsylvania). A combination vaccine (hepatitis A
and hepatitis B) for use in adults, Twinrix® (GlaxoSmithKline Biologicals,
Pittsburgh, Pennsylvania), also is available. The recommended HBV dose
varies by product and age of recipient ( Table 3 ).
When selecting a hepatitis B vaccination schedule, the health-care provider
should consider the need to achieve completion of the vaccine series.
Approved adolescent and adult schedules for both monovalent hepatitis B
vaccine (i.e., Engerix-B® and Recombivax HB®) include the following: 0, 1,
and 6 months; 0, 1, and 4 months; and 0, 2, and 4 months. A 4-dose schedule
of Engerix-B® at 0, 1, 2, and 12 months is licensed for all age groups. A
2-dose schedule of Recombivax HB® adult formulation (10 µg) is licensed for
adolescents aged 11--15 years. When scheduled to receive the second dose,
adolescents aged >15 years should be switched to a 3-dose series, with doses
2 and 3 consisting of the pediatric formulation (5 µg) administered on an
appropriate schedule. Twinrix® may be administered to persons aged ≥18
years at risk for both HAV and HBV infections at 0, 1, and 6 months.
Hepatitis B vaccine should be administered IM in the deltoid muscle and may
be administered simultaneously with other vaccines. For adolescents and
adults, the needle length should be 1--2 inches, depending on the
recipient's weight (1 inch for females weighing <70 kg), 1.5 inches for
males weighing <120 kg; and 2 inches for males weighing >120 kg and females
>100 kg). A 22- to 25-gauge needle is recommended. If the vaccine series is
interrupted after the first or second dose of vaccine, the missed dose
should be administered as soon as possible. The series does not need to be
restarted after a missed dose.
In adolescents and healthy adults aged <40 years, approximately 30%--55%
acquire a protective antibody response (anti-HBs ≥10 mIU/mL) after the
first vaccine dose, 75% after the second, and >90% after the third.
Vaccine-induced immune memory has been demonstrated to persist for at least
15--20 years. Periodic testing to determine antibody levels in
immunocompetent persons is not necessary, and booster doses of vaccine are
not recommended.
Hepatitis B vaccination is generally well-tolerated by the majority of
recipients. Pain at the injection site and low-grade fever are reported by a
minority of recipients. Evidence for a causal association between receipt of
hepatitis B vaccination and anaphylaxis exists, which is estimated to occur
in 1 of 1.1 million doses of vaccine administered among children and
adolescents; no deaths have been reported after anaphylaxis. Vaccine is
contraindicated in persons with a history of anaphylaxis after a previous
dose of hepatitis B vaccine and in persons with a known anaphylactic
reaction to any vaccine component. No evidence for a causal association has
been demonstrated for other adverse events reported after administration of
hepatitis B vaccine.
Preexposure Vaccination
Hepatitis B vaccination is recommended for all unvaccinated adolescents, all
unvaccinated adults at risk for HBV infection, and all adults seeking
protection from HBV infection. For adults, acknowledgement of a specific
risk factor is not a requirement for vaccination.
Hepatitis B vaccine should be routinely offered to all unvaccinated persons
attending STD clinics and to all unvaccinated persons seeking treatment for
STDs in other settings. Other settings where all unvaccinated adults should
be assumed to be at risk for hepatitis B and should receive hepatitis B
vaccination include correctional facilities, facilities providing drug abuse
treatment and prevention services, health-care settings serving MSM, and HIV
testing and treatment facilities. All persons who receive clinical services
in these settings should be offered hepatitis B vaccine, unless they have a
reliable vaccination history (i.e., a written, dated record of each dose of
a complete series). In all settings, vaccination should be initiated even
though completion of the vaccine series might not be ensured.
Prevaccination Antibody Screening
Prevaccination serologic testing for susceptibility may be considered to
reduce the cost of vaccinating adult populations that have an expected high
prevalence of HBV infection (i.e., >20%--30%) (e.g., IDUs and MSM
[especially in older age groups]). In addition, prevaccination testing for
susceptibility is recommended for unvaccinated household, sexual, and
needle-sharing contacts of HBsAg-positive persons.
Anti-HBc is the test of choice for prevaccination testing; persons who are
anti-HBc--positive should be tested for HBsAg. If persons are determined to
be HBsAg negative, no further action is required. If persons are determined
to be HBsAg positive, the person should be referred for medical follow-up,
including counseling and evaluation for antiviral treatment (see Management
of HBsAg-Positive Persons). In addition, all household members, sex
partners, and needle-sharing partners of HBsAg-positive persons should be
vaccinated.
Serologic testing should not be a barrier to vaccination of susceptible
persons, especially in populations that are difficult to access. In the
majority of situations, the first vaccine dose should be administered
immediately after collection of the blood sample for serologic testing.
Vaccination of persons who are immune to HBV infection because of current or
previous infection or vaccination does not increase the risk for adverse
events.
Postvaccination Testing for Serologic Response
Serologic testing for immunity is not necessary after routine vaccination of
adolescents or adults. Testing after vaccination is recommended for persons
whose subsequent clinical management depends on knowledge of their immune
status (e.g., health-care workers or public safety workers at high risk for
continued percutaneous or mucosal exposure to blood or body fluids). In
addition, testing is recommended for 1) HIV-infected persons and other
immunocompromised persons to determine the need for revaccination and the
type of follow-up testing; and 2) sex and needle-sharing partners of
HBsAg-positive persons to determine the need for revaccination and for other
methods to protect themselves from HBV infection.
If indicated, testing should be performed 1--2 months after administration
of the last dose of the vaccine series by using a method that allows
determination of a protective level of anti-HBs (≥10 mIU/mL). Persons
determined to have anti-HBs levels of <10 mIU/mL after the primary vaccine
series should be revaccinated with a 3-dose series, followed by anti-HBs
testing 1--2 months after the third dose. Persons who do not respond to
revaccination should be tested for HBsAg. If HBsAg positive, the person
should receive appropriate management (see Management of HBsAg-Positive
Persons); if HBsAg negative, the person should be considered susceptible to
HBV infection and counseled concerning precautions to prevent HBV infection
and the need for HBIG PEP for any known exposure (see PEP).
Postexposure Prophylaxis
Both passive-active PEP with HBIG and hepatitis B vaccination and active PEP
with hepatitis B vaccination alone have been demonstrated to be highly
effective in preventing transmission after exposure to HBV.[2] HBIG alone
also has been demonstrated to be effective in preventing HBV transmission,
but with the availability of hepatitis B vaccine, HBIG typically is used as
an adjunct to vaccination.
Exposure to HBsAg-Positive Source. Unvaccinated persons or persons known not
to have responded to a complete hepatitis B vaccine series should receive
both HBIG and hepatitis vaccine as soon as possible (preferably ≤24
hours) after a discrete, identifiable exposure to blood or body fluids that
contain blood from an HBsAg-positive source ( Table 5 ). Hepatitis B vaccine
should be administered simultaneously with HBIG in a separate injection
site, and the vaccine series should be completed by using the
age-appropriate vaccine dose and schedule ( Table 3 ). Exposed persons who
are in the process of being vaccinated but who have not completed the
vaccine series should receive the appropriate dose of HBIG (i.e., 0.06
mL/kg) and should complete the vaccine series. Exposed persons who are known
to have responded to vaccination are considered protected and need no
further vaccine doses. Persons who have written documentation of a complete
hepatitis B vaccine series and who did not receive postvaccination testing
should receive a single vaccine booster dose. Alternatively, these persons
can be managed according to guidelines for management of persons with
occupational exposure to blood or body fluids that contain blood.[207]
Exposure to Source with Unknown HBsAg Status. Unvaccinated persons who have
a discrete, identifiable exposure to blood or body fluids containing blood
from a source with unknown HBsAg status should receive the hepatitis B
vaccine series, with the first dose initiated as soon as possible after
exposure (preferably within 24 hours) and the series completed by using the
age-appropriate dose and schedule. Exposed persons who are not fully
vaccinated should complete the vaccine series. Exposed persons with written
documentation of a complete hepatitis B vaccine series require no further
treatment.
Special Considerations
Pregnancy. All pregnant women receiving STD services should be tested for
HBsAg, regardless of whether they have been previously tested or vaccinated.
All HBsAg-positive pregnant women should be reported to state and local
perinatal hepatitis B prevention programs. HBsAg-negative pregnant women
seeking STD treatment who have not been previously vaccinated should receive
hepatitis B vaccination. Additional information regarding management of
HBsAg-positive pregnant women and their infants is available at
http://www.cdc.gov/mmwr/PDF/rr/rr5416.pdf.
HIV Infection. HIV infection can impair the response to hepatitis B
vaccination. HIV-infected persons should be tested for anti-HBs 1--2 months
after the third vaccine dose (see Postvaccination Testing for Serologic
Response). Modified dosing regimens, including a doubling of the standard
antigen dose and administration of additional doses, might increase the
response rate.
Management of HBsAg-Positive Persons
This section provides recommendations for management of all HBsAg-positive
persons. Additional recommendations for management of HBsAg-positive persons
who are coinfected with HIV are available at
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5315a1.htm.
All persons with HBsAg-positive laboratory results should be reported to the
state or local health department.
To verify the presence of chronic HBV infection, HBsAg-positive persons
should be retested. The absence of IgM anti-HBc or the persistence of HBsAg
for 6 months indicates chronic HBV infection.
Persons with chronic HBV infection should be referred for evaluation to a
physician experienced in the management of CLD. Some patients with chronic
hepatitis B will benefit from early intervention with antiviral treatment or
screening to detect HCC at an early stage.
Household, sexual, and needle-sharing contacts of chronically infected
persons should be identified. Unvaccinated sex partners and household and
needle-sharing contacts should be tested for susceptibility to HBV infection
(see Prevaccination Antibody Screening) and should receive the first dose of
hepatitis B vaccine immediately after collection of the blood sample for
serologic testing. Susceptible persons should complete the vaccine series by
using an age-appropriate vaccine dose and schedule. Persons who are fully
vaccinated should complete the vaccine series.
Sex partners of HBsAg-positive persons should be counseled to use methods
(e.g., condoms) to protect themselves from sexual exposure to infectious
body fluids (e.g., semen and vaginal secretions), unless they have been
demonstrated to be immune after vaccination (anti-HBs ≥10 mIU/mL) or
previously infected (anti-HBc positive).
To prevent or reduce the risk for transmission to others, HBsAg-positive
persons should be advised concerning the risk for transmission to household,
sexual, and needle-sharing contacts and the need for such contacts to
receive hepatitis B vaccination. HBsAg-positive persons also should be
advised to
--- use methods (e.g., condoms) to protect nonimmune sex partners from
acquiring HBV infection from sexual activity until the partner can be
vaccinated and immunity documented;
--- cover cuts and skin lesions to prevent the spread of infectious
secretions or blood;
--- refrain from donating blood, plasma, body organs, other tissue, or
semen; and
--- refrain from sharing household articles (e.g., toothbrushes, razors, or
personal injection equipment) that could become contaminated with blood.
To protect the liver from further harm, HBsAg-positive persons should be
advised to
--- avoid or limit alcohol consumption because of the effects of alcohol on
the liver;
--- refrain from starting any new medicines, including OTC and herbal
medicines, without checking with their health-care provider; and
--- obtain vaccination against hepatitis A if liver disease is determined to
be present.
When seeking medical or dental care, HBsAg-positive persons should be
advised to inform those responsible for their care of their HBsAg status so
that they can be appropriately evaluated and managed. Information regarding
HBsAg-positive women who are pregnant is available in this report (see
Special Populations, Pregnant Women). Other counseling messages also should
be considered.
--- HBV is not spread by hugging, coughing, food or water, sharing eating
utensils or drinking glasses, or casual contact.
--- Persons should not be excluded from work, school, play, child care, or
other settings because they are infected with HBV.
--- Involvement with a support group might help patients cope with chronic
HBV infection.
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MMWR. 2006;55(30):1-94. ©2006 Centers for Disease Control and Prevention
(CDC)
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发表于 2006-9-20 17:24
