Page 359 - Review of Medical Microbiology and Immunology ( PDFDrive )

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PART IV Clinical Virology
348
Important diagnostic tests
Incubation
Convalescence
Prevention involves the use of either the vaccine or hyper-
period
acute disease
Early
Late
immune globulin or both.
Anti-
Anti-HBs
HBsAg
HBsAg
HBc
(anti-HBc)
(anti-HBc)
(1) The vaccine (e.g., Recombivax) contains HBsAg
A
1
0
2
5
4
6
3
vaccine is highly effective in preventing hepatitis B and has
few side effects. The seroconversion rate is approximately
95% in healthy adults. It is indicated for people who are
DNA polymerase Months after exposure 7 8 Anti-HBc produced in yeasts by recombinant DNA techniques. The
frequently exposed to blood or blood products, such as
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HBV virions
certain health care personnel (e.g., medical students, sur-
geons, and dentists), patients receiving multiple transfu-
HBsAg
disease, and abusers of illicit intravenous drugs. Travelers
Titer
who plan a long stay in areas of endemic infection, such as
Anti-HBs
many countries in Asia and Africa, should receive the vac-
cine. The U.S. Public Health Service recommends that all
newborns and adolescents receive the vaccine.
Level of
detection
At present, booster doses after the initial three-dose regi-
B
4
0
1
2
3
declined in immunized patients who are at high risk, such as
Months after exposure
dialysis patients, then a booster dose should be considered.
Elevated 5 6 7 8 men are not recommended. However, if antibody titers have
Widespread immunization with the HBV vaccine has
transaminases
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significantly reduced the incidence of hepatocellular carci-
Symptoms
C
noma in children. A vaccine called Twinrix that contains
against both hepatitis B and hepatitis A.
(2) Hepatitis B immune globulin (HBIG) contains a high
titer of HBsAb. It is used to provide immediate, passive pro-
tection to individuals known to be exposed to HBsAg-
positive blood (e.g., after an accidental needle-stick injury).
Titer
Precise recommendations for use of the vaccine and
HBIG are beyond the scope of this book. However, the
recommendation regarding one common concern of medi-
Total anti-HBc
HBsAg
cal students, the needle-stick injury from a patient with
HBsAg-positive blood, is that both the vaccine and HBIG
mebooksfree.com mebooksfree.com 4 5 mebooksfree.com newborn whose mother is HBsAg-positive. This regimen is mebooksfree.com
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be given (at separate sites). This is true even if the patient’s
Level of
detection
blood is HBeAb positive.
Both the vaccine and HBIG should also be given to a
6
2
1
3
0
Years after exposure
Months after exposure
D
very effective in reducing the infection rate of newborns
FIGURE 41–4
A: Important diagnostic tests during various
whose mothers are chronic carriers. The regimen of vac-
stages of hepatitis B. B: Serologic findings in a patient with acute
cine plus HBIG in those with needle-stick injuries and in
hepatitis B. C: Duration of increased liver enzyme activity and of
neonates is a good example of passive–active immuniza-
symptoms in a patient with acute hepatitis B. D: Serologic findings in
tion, in which both immediate protection and long-term
a patient with chronic hepatitis B. anti-HBc, hepatitis B core antibody;
anti-HBe, hepatitis B e antibody; anti-HBs, hepatitis B surface anti-
The effectiveness of Cesarean section to reduce HBV
body; HBeAg, hepatitis B e antigen; HBsAg, hepatitis B surface anti-
infection of neonates is uncertain. It is currently not recom-
gen; HBV, hepatitis B virus. (Adapted from Hollinger FB, Dienstag JL. Hepatitis
mended. Breast feeding of immunized neonates by mothers
viruses. In: Lennette EH, et al., eds. Manual of Clinical Microbiology. 4th ed. Washington, protection are provided.
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who are chronic carriers entails little risk of infection of the
DC: ASM Press; 1985.)
neonate.
All blood for transfusion should be screened for HBsAg.
caution because recovery of cell-mediated immunity can
result in an exacerbation of hepatitis (immune reconstitu-
donate blood, because non-A, non-B viruses may be pres-
ent. Screening of high-risk populations to detect chronic
tion syndrome, IRIS). Consideration should be given to
carriers using serologic testing should be done because
treat the HBV infection prior to starting HAART.
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