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| Hepatitis A disease
and transmission issues |
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| What is
hepatitis A? |
 |
| Hepatitis A is a liver disease caused
by hepatitis A virus (HAV). |
|
| What are the signs and symptoms of
hepatitis A? |
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| Illness caused by HAV infection typically has an abrupt onset that
can include fever, malaise, anorexia, nausea, abdominal discomfort, dark
urine, and jaundice. The likelihood of having symptoms with HAV infection
is related to age. In children younger than age 6 years, 70% of infections
are asymptomatic. When illness does occur in young children, it is typically
not accompanied by jaundice. In older children and adults, infection
typically is symptomatic, with jaundice occurring in more than 70% of
patients.
Hepatitis A signs and symptoms usually
last less than 2 months, although 10% to 15% of symptomatic persons
have prolonged illness (usually referred to as relapsing hepatitis
A) lasting up to 6 months. |
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| How is HAV transmitted? |
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Person-to-person spread through the fecal-oral route is the primary means of HAV transmission. In 2007, however, among cases for which information regarding exposures during the incubation period was collected, the most frequently identified risk factor for hepatitis A was international travel (18%). Historically, sexual and household contact with another person with hepatitis A had been among the most frequently identified risk. In 2007, these types of contacts accounted for only 8% of reported cases. Casual contact, as in the usual office, factory, or school setting does not transmit the virus.
|
Common-source outbreaks and sporadic cases
also can occur from exposure to fecally- contaminated food or water.
Uncooked HAV-contaminated foods have been recognized as a source of
outbreaks. Cooked foods also can transmit HAV if the temperature during
food preparation is inadequate to kill the virus or if food is contaminated
after cooking, as occurs commonly in outbreaks associated with infected
food handlers. |
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| What is the incubation period for
hepatitis A? |
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| HAV can produce either asymptomatic or symptomatic
infection in humans after an average incubation period of 28 days (range:
15-50 days). |
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| How is HAV shed? |
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| In infected persons, HAV replicates in the liver, is excreted in
bile, and is shed in stool. Peak infectivity of infected persons occurs
during the 2-week period before onset of jaundice or elevation of liver
enzymes, when concentration of virus in stool is highest. Concentration
of virus in stool declines after jaundice appears. Children can shed
HAV for longer periods than do adults, lasting up to 10 weeks after onset
of clinical illness. |
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| How common is HAV infection in the
United States? |
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| In 2007, 2,979 acute clinical cases were
reported to CDC's surveillance system. Approximately 25,000 new
infections were estimated to have occurred. |
| |
| What is the seroprevalence of HAV
infection in the United States? |
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| As evidenced by the last National Health
and Nutrition Examination Survey done during 1988-1994, approximately
30% of the U.S. population had serologic evidence of previous HAV
infection. |
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| Do people die from hepatitis A? |
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| Yes. According to CDC, among persons who are ill with hepatitis A,
approximately 0.8% die; of persons older than age 59, the fatality
rate reaches 2.6%. Persons with chronic liver disease are also at increased
risk for acute liver failure. |
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| Who is most at risk for acquiring HAV infection? |
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| Persons who are at increased risk for
HAV infection include the following:
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| • |
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certain travelers to
countries that have high or intermediate endemicity of HAV infection
(for map of endemic areas, see
http://wwwn.cdc.gov/travel/default.aspx) |
| • |
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men who have sex with
men (MSM) |
| • |
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users of injection and noninjection
illegal drugs |
| • |
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persons with clotting-factor disorders |
| • |
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persons working with nonhuman primates |
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| Discuss
the tests commonly used to diagnose hepatitis A. |
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| Hepatitis A cannot be differentiated
from other types of viral hepatitis on the basis of clinical or epidemiological
features alone. Appropriate blood tests must be used. |
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| • |
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Anti-HAV: Total antibody to HAV.
This diagnostic test detects total antibody of both IgG and IgM
subclasses of HAV. Its presence indicates either acute or resolved
infection. |
| • |
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IgM anti-HAV: IgM antibody
is a subclass of anti-HAV. Its presence indicates a recent infection
with HAV (6 months or less). It is used to diagnose acute (recently
acquired) hepatitis A. |
|
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| Total anti-HAV, which appears early in
the course of infection, remains detectable for the person's lifetime
and provides lifelong protection against the infection/disease. To
confirm a diagnosis of acute HAV infection, serologic testing for
IgM anti-HAV is required. In the majority of persons, serum IgM anti-HAV
becomes detectable 5 to 10 days before onset of symptoms and lasts
about 6 months. However, there have been reports of persons who test
positive for IgM anti-HAV for up to a year or more following infection.
For a complete educational program on the interpretation of viral
hepatitis serology that includes hepatitis
A serology, visit
www.cdc.gov/hepatitis/Resources/Professionals/Training/SerologyStart.htm
or the hepatitis web study at:
http://depts.washington.edu/hepstudy |
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| I read that some hepatitis A lab tests
yield false positive results. Please tell me more about this. |
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| In 2005, state health departments and CDC investigated persons with
positive serologic tests for acute HAV infection (i.e., IgM anti-HAV)
whose illness was not consistent with the surveillance case definition
for acute hepatitis A. Findings in this investigation indicate that most
persons who were tested for IgM anti-HAV and who did not have illness
consistent with acute viral hepatitis had false positive test results.
Thus, healthcare providers should limit use of IgM anti-HAV testing to
persons with evidence of clinical hepatitis or to those who have had
recent exposure to an HAV-infected person. Use of IgM anti-HAV as a screening
tool for asymptomatic persons or as part of testing panels for the workup
of non-acute liver function abnormalities should be discouraged. For
more information, read the MMWR article (5/13/05) on this topic at
www.cdc.gov/mmwr/preview/mmwrhtml/mm5418a1.htm |
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| Can HAV be transmitted by blood? |
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| Yes. On rare occasions, HAV infection
has been transmitted by transfusion of blood or blood products collected
from donors during the viremic phase
of their infection (i.e., when HAV is in the donor's blood). |
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| Is HAV transmitted by saliva? |
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| In experimentally infected nonhuman primates,
HAV has been detected in saliva during the incubation period; however,
transmission by human
saliva has not been reported. |
| |
| How common is HAV transmission in
hospital
settings? |
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| Hospital-acquired HAV infection is rare.
Outbreaks have occasionally been observed in neonatal intensive care
units when infants acquire infection
from HAV-infected transfused blood and subsequently transmit HAV to other
infants and staff. Outbreaks of hepatitis A caused by transmission from
adult patients to healthcare workers (HCWs) are typically associated
with fecal incontinence, although the majority of hospitalized patients
who have hepatitis A are admitted after onset of jaundice, when they
are beyond the point of peak infectivity. Data from serologic surveys
of HCWs have not indicated an increased prevalence of HAV infection in
these groups compared with that in control populations. |
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| How stable is HAV in the environment? |
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| Depending on conditions, HAV can be
stable in the environment for months. Heating foods at temperatures
greater than 185°F (85°C) for 1 minute or disinfecting surfaces with a
1:100 dilution of sodium hypochlorite (i.e., household bleach) in tap
water will inactivate HAV. |
| |
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Do people with hepatitis A develop
chronic disease? |
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| No, there is no chronic (long-term) infection. Once you have had
HAV infection and recovered, you cannot get
it again. |
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| What is the best way to prevent HAV infection? |
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| Vaccination with the full 2-dose
series of hepatitis A vaccine is the best way to prevent HAV infection.
Immune globulin (IG) can also be used for short-term protection in
certain situations. |
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| Who is recommended to receive
hepatitis A vaccine? |
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| According to CDC, people recommended for
vaccination include |
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| • |
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All children at age 1
year (12-23 months). Children who are not vaccinated by age 2 years
should be vaccinated as soon as feasible. |
| • |
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People age 12 months or
older who are traveling to or working in an area of the world except
the United States, Canada, Western Europe, Japan, New Zealand, and
Australia |
| • |
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Men who have sex with men |
| • |
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Users of illicit drugs, injectable
or noninjectable |
| • |
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Previously unvaccinated people who
anticipate having close personal contact with an international
adoptee from a country of high or intermediate endemicity during the
first 60 days following the adoptee's arrival in the U.S. |
| • |
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People who have blood clotting
disorders |
| • |
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People who work with HAV-infected
primates or with HAV in a research laboratory setting (no other
groups have been shown to be at increased risk for HAV infection
because of occupational exposure) |
| • |
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People with chronic liver disease |
| • |
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Any person who wishes to be immune
to hepatitis A |
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| Hepatitis A vaccine is not routinely
recommended or healthcare workers, sewage workers, or day care
providers. |
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| Is there any reason not to give hepatitis
A
vaccine to a person who requests it? |
|
| No, unless the person is allergic to
any of the vaccine components. Hepatitis A vaccine is safe and effective
and is recommended for any person who wishes
to
obtain immunity. |
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| Which children should be vaccinated
against HAV infection on a routine basis? |
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| All children should receive 2 doses of
hepatitis A vaccine beginning at age 1 year (i.e., 12-23 months). The 2
doses in the series should be administered at least 6 months apart.
Children who are not vaccinated by age 2 years can be vaccinated at
subsequent visits. States, counties, and communities with existing
hepatitis A vaccination programs for children age 2-18 years are
encouraged to maintain these programs. Efforts focused on routinely
vaccinating 1-year-olds should enhance, not replace, ongoing programs
directed at a broader population of children. For a copy of the ACIP
recommendations on hepatitis A, go to
www.cdc.gov/mmwr/PDF/rr/rr5507.pdf |
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| I thought hepatitis A vaccine (HepA)
was recommended for all children. Why does the bar on CDC's childhood
immunization schedule indicate that HepA should be routinely given to
children ages 12 through 23 months, but not be given to children age 2
years and older unless they are in certain high risk groups? In our
practice in a historically "low-risk" state, we currently give HepA to
any unvaccinated child. Is this incorrect? |
|
|
No. Though the ACIP
recommendation says children ages 12 through 23 months should routinely
be vaccinated with 2 doses of HepA, it also says, "children who are not
vaccinated by age 2 years can be vaccinated at subsequent visits."
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| What are the new recommendations for
postexposure prophylaxis for hepatitis A? |
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| The new CDC recommendations published in
October 2007 (www.cdc.gov/mmwr/preview/mmwrhtml/mm5641a3.htm),
state that hepatitis A vaccine is preferred over immune globulin (IG)
for postexposure prophylaxis for persons age 12 months-40 years who have
recently been exposed to hepatitis A virus (HAV) and who have not
previously received hepatitis A vaccine. Previously, IG was preferred.
Persons age 12 months-40 years should receive a single dose of
single-antigen hepatitis A vaccine or immune globulin (0.02 mL/kg) as
soon as possible after exposure. For persons older than 40 years, IG is
preferred, although vaccine can be used if IG is unavailable. It is
important to note that IG should be given within 2 weeks of exposure to
HAV. IG should also be used for children younger than age 12 months,
immunocompromised persons, persons who have chronic liver disease or
other chronic medical conditions, and persons for whom vaccine is
contraindicated. The following are situations in which postexposure
treatment is indicated: |
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| • |
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Having close, ongoing
personal contact with an HAV-infected person |
| • |
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Working in or attending
a child care center where hepatitis A cases are occurring |
| • |
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Having common-source exposure (e.g.,
eating HAV-infected food in a restaurant) |
| • |
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Having close contact with index
patients in schools, hospitals, and work settings when an
epidemiological investigation indicates that a common-source
exposure has occurred. |
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| |
| Persons who have received a dose of
hepatitis A vaccine before exposure to HAV do not need to receive a
second dose of vaccine until at least 6 months following the first dose.
Because HAV infection cannot be reliably diagnosed on clinical
presentation alone, serologic confirmation of HAV infection in the index
patientis recommended using the IgM anti-HAV serologic test. If the
index patient tests positive, postexposure treatment of sex and
household contacts is recommended (as described above). Serologic
screening of contacts for HAV immunity before administering postexposure
prophylaxis is not recommended because screening results in delayed
prophylaxis. It is critical that you contact your local or state health
department to get guidance on when or if postexposure treatment is
recommended. |
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| When should prevaccination testing for
susceptibility be performed? |
|
| Testing is not indicated for children
because of their expected low prevalence of infection. In populations
that have expected high rates of previous HAV infection, prevaccination
screening may be considered to reduce costs. Persons to consider for
testing include: (1) adults who were either born in or lived for extensive
periods in geographic areas that have a high or intermediate endemicity
of hepatitis A; (2) older adolescents and adults in certain population
groups (e.g., American Indians, Alaska Natives, Hispanics); and (3) adults
in risk groups that have a high prevalence of infection (e.g., men who
have sex with men, illegal drug users). In addition, HAV testing may
be cost effective among persons older than age 40 years. |
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| When should postvaccination testing
be performed? |
|
| Postvaccination testing is not indicated because of the high rate
of vaccine response among adults and children. In addition, not all testing
methods approved for routine diagnostic use in the United States have
the sensitivity to detect low, but protective, anti-HAV concentrations
after vaccination. |
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Vaccination
recommendations for special groups |
Back to top |
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| We've heard there is a new
recommendation for giving hepatitis A vaccine to people who will be in
contact with recently adopted children. Would you give us the details? |
|
| Yes. ACIP voted in February 2009 to
recommend vaccination against HAV infection for all previously
unvaccinated people who anticipate having close personal contact with an
international adoptee from a country of high or intermediate endemicity
during the first 60 days following the adoptee's arrival in the U.S. In
addition to the adoptee's new parents and siblings, this group could
include grandparents and other members of the extended family,
caregivers, and healthcare providers. Ideally, the first dose of
hepatitis A vaccine should be given to close contacts as soon as
adoption is planned but no later than 2 weeks prior to the arrival of
the adoptee. A second dose should be given no sooner than 6 months after
the first dose. |
|
| Should HCWs be vaccinated routinely
against hepatitis A? |
|
| No. A number of studies have shown that
HCWs are not at increased risk of HAV infection because of their
occupation. However, if the HCW is going to work (or
vacation) in a country with a high or intermediate endemic rate of HAV infection,
he/she is at risk of HAV infection and should be vaccinated. The only HCWs for
whom hepatitis A vaccine is routinely recommended are those who work with primates
or live HAV. |
|
| Should daycare workers be routinely
vaccinated against hepatitis A? |
|
| No. Although child care centers might
have been the source of outbreaks of hepatitis A in certain communities,
disease in child care centers more commonly reflects
extended transmission from
the community. |
|
| Can pregnant women receive hepatitis
A vaccine? |
|
| The safety of hepatitis A vaccination
during pregnancy has not been determined; however, because hepatitis
A vaccine is produced from inactivated
HAV, the theoretical risk to the developing fetus is expected to be low.
The risk associated with vaccination should be weighed against the risk
for hepatitis A in pregnant women who might be at high risk for exposure
to HAV. |
|
| Can lactating women receive hepatitis
A vaccine? |
|
| Yes. Hepatitis A vaccine is an inactivated
vaccine and poses no harm to the nursing infant. |
|
| Why is hepatitis A vaccination recommended
for persons with chronic liver disease? |
|
| Although not at increased risk for HAV infection, persons with chronic
liver disease are at increased risk for fulminant hepatitis A if they
should become infected with HAV. For this reason, hepatitis A vaccination is
recommended for them. |
|
| Can hepatitis A vaccine be given to
immunocompromised
persons? |
|
| Yes. If an immunocompromised person has a risk factor that places
them at increased risk of hepatitis A (e.g., MSM), they should be vaccinated
with hepatitis A vaccine. |
|
| I have a patient on interferon for
hepatitis C, but I want to give him hepatitis A vaccine. Is it
okay
to vaccinate him against hepatitis A while he is on interferon? |
|
| Yes. Hepatitis A vaccine should be given
to all susceptible patients with chronic liver disease. Hepatitis
A vaccine is very immunogenic and the patient's diminished
immune status due to interferon should not affect the immunogenicity and effectiveness
of the vaccine, although there are no data to support that statement. |
|
| Why isn't hepatitis A vaccine recommended
for sewage and solid waste disposal workers? |
|
| Existing data do not support the use of
hepatitis A vaccine routinely in this setting. In published reports of three serologic surveys
conducted among United States wastewater workers and appropriate comparison populations,
no substantial or consistent increase in the prevalence of anti-HAV was identified
among wastewater workers. No work-related instances of HAV transmission have
been reported among wastewater workers in the United States. |
|
| Are persons with developmental disabilities
at risk of HAV infection? |
|
| Historically, HAV infection was highly
endemic in institutions for persons with developmental disabilities.
As fewer children have been
institutionalized and as conditions in institutions have improved, the
incidence and prevalence of HAV infection have decreased, although outbreaks
can occur in these settings. Children with developmental disabilities
should receive hepatitis A vaccine according to U.S. routine vaccine
recommendations. Employees in these institutional settings are not recommended
to receive routine hepatitis A vaccination; however, employees and residents
in these settings should receive hepatitis B
vaccination routinely. |
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| Hepatitis A vaccines,
schedules, and dosing |
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| What are the hepatitis A vaccines
that are approved for use in the United States? |
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| Recommended
dosages and schedules of hepatitis A vaccines |
| Vaccine |
Age
group |
Dose |
Volume |
#
Doses |
Schedule |
Havrix
(GlaxoSmithKline [GSK]) |
1-18
years |
720
El.U.* |
0.5
ml |
2 |
0, 6-12
mos. |
| 19 years
and older |
1440
El.U.* |
1.0
ml |
2 |
0, 6-12
mos. |
Vaqta
(Merck & Co.) |
1-18
years |
25
U* |
0.5
ml |
2 |
0, 6-18
mos. |
| 19 years
and older |
50 U* |
1.0
ml |
2 |
0, 6-18
mos. |
*El.U. = Elisa Units **U = Units |
| |
| Combination
vaccine using hepatitis A and hepatitis B vaccines |
| Vaccine |
Age
group |
Antigens
used |
Volume |
# Doses |
Schedule |
Twinrix
(GlaxoSmithKline [GSK]) |
18
years and older |
Havrix (720
El.U.) combined
with Engerix-B (20 mcg) |
1.0
ml |
3 |
0, 1,
6 mos. |
| 4 |
0, 7,
21-30 days, 12 months |
|
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| Are hepatitis A vaccine brands interchangeable? |
|
| Yes, a number of studies indicate that
the two brands of hepatitis A vaccine, Havrix (GlaxoSmithKline) and Vaqta
(Merck),
are interchangeable. |
|
| Can hepatitis A vaccine be given concurrently
with other vaccines? |
|
| Yes. Other inactivated and/or live virus
vaccines can be administered at the same time as hepatitis A vaccine,
but should be given at a different
anatomical site, if possible. If given in the same muscle, separate the
injections by
a minimum distance of 1 inch. |
|
| I would like more information about
Twinrix, the combination hepatitis A and B vaccine. |
|
| Twinrix (GlaxoSmithKline) is an
inactivated combination vaccine containing both hepatitis A virus (HAV)
and HBV antigens. The vaccine contains 720 EL.U. of hepatitis A antigen
(half of the Havrix adult dose) and 20 mcg of hepatitis B antigen (the
full Engerix-B adult dose). In the U.S., Twinrix is licensed for use in
people who are age 18 years or older. It can be administered to persons
who are at risk for both hepatitis A and hepatitis B, such as certain
international travelers, men who have sex with men, illegal drug users,
or to persons who simply want to be immune to both diseases. Primary
immunization consists of 3 doses given intramuscularly on a 0, 1, and 6
month schedule. In March 2007, the FDA also approved a 4-dose schedule
for Twinrix. It consists of 3 doses given within 3 weeks, followed by a
booster dose at 12 months (0, 7 days, 21-30 days, and 12 months). The
4-dose schedule could benefit individuals needing rapid protection from
hepatitis A and hepatitis B, such as persons traveling to
high-prevalence areas imminently and emergency responders, especially
those being deployed to disaster areas overseas. Twinrix cannot be used
for postexposure prophylaxis. |
|
| By what method should hepatitis A
vaccine be administered? |
|
| Hepatitis A vaccine should be administered
intramuscularly (IM), using the appropriate injection site and needle
size as determined by
the patient's age and body mass. |
|
| Is hepatitis A vaccine available to
children through the Vaccines for Children (VFC) program? |
|
| Yes, VFC-supported hepatitis A vaccine
is available for children 12 months through 18 years who are VFC-eligible
and who meet the criteria
for vaccination with hepatitis A vaccine. In addition, combination hepatitis
A and hepatitis B vaccine (Twinrix by GSK) is also available for people
who are age 18 years who are
VFC-eligible. |
|
| What contraindications and precautions
should be followed when administering hepatitis A vaccine? |
|
| Hepatitis A vaccine is contraindicated for people with a history of a severe allergic reaction to a previous dose of hepatitis A vaccine or to a vaccine component. As with all other vaccines, there is a precaution when giving it to anyone who is moderately or severely ill. Information on the use of hepatitis A vaccine in pregnancy is noted in a previous question. |
|
| What local reactions might occur after
administration of hepatitis A vaccine? |
|
| No serious adverse events
have been attributed definitively to hepatitis A vaccine. Among
adults, the most frequently reported side effects are soreness
at the site of the injection and headache. In children, the most
frequently reported side effect is soreness at the injection site.
The frequency of side effects after administration of Twinrix is
similar to those reported when the two single-antigen vaccines
were administered. |
|
| What happens if dose #2 of hepatitis
A vaccine is delayed? |
|
| You do not need to start the series over
again. The immunogenicity of 1 dose of hepatitis A vaccine is 94%
to 100%. Immunogenicity is considered to be equal
to efficacy; however, the vaccine series should be completed to assure long-term
protection. |
|
| To complete a 21-year-old patient's
hepatitis A vaccine series, how many adult doses should I give if the
patient received a single dose of pediatric hepatitis A vaccine 5 years
ago? |
|
| You should give the patient one dose of
adult HepA to complete the 2-dose series. There is never a need to start
a vaccine series over. |
|
| One of our staff gave a dose of
pediatric hepatitis A vaccine to an adult patient by mistake. How do we
remedy this error? |
|
| If less than a full age-appropriate dose
of any vaccine is given, the dose should not be counted. The person
should be revaccinated with the appropriate dose as soon as possible. |
| |
| I have seen adults who have had 1
or 2 doses of Twinrix, but we only carry single-antigen vaccine
in our practice. How should we complete their vaccination series
with single-antigen vaccines? |
|
| Twinrix is licensed as a 3-dose series
for persons age 18 years and older. If Twinrix is not available or if
you choose not to use Twinrix to complete the Twinrix series, you should
do the following: If 1 dose of Twinrix was given, complete the series
with 2 adult doses of hepatitis B vaccine and 2 adult doses of hepatitis
A vaccine. If 2 doses of Twinrix were given, complete the schedule with
1 adult dose of hepatitis A vaccine and 1 adult dose of hepatitis B
vaccine. |
|
Another way to consider this is as
follows:
A dose of Twinrix contains a standard adult dose of hepatitis B vaccine
and a pediatric dose of hepatitis A vaccine. Thus, a dose of Twinrix can
be substituted for any dose of the hepatitis B series but not for any
dose of the hepatitis A series. |
|
| • |
|
Any combination of 3
doses of adult hepatitis B or 3 doses of Twinrix = a complete series
of hepatitis B vaccine. |
| • |
|
One dose of Twinrix + 2
doses of adult hepatitis A = a complete series of hepatitis A
vaccine. |
| • |
|
Two doses of Twinrix + 1
dose of adult hepatitis A = a complete series of hepatitis A
vaccine. |
|
|
| We're thinking of using Twinrix and
we're wondering whether we can use it for doses #1 and #3 only
and use single antigen hepatitis B vaccine for dose #2? |
|
| No. Twinrix contains 50% less hepatitis
A antigen component than Havrix, GSK's monovalent hepatitis A vaccine
[720 vs. 1440 El. U.], so the patient would not
receive the recommended dose of hepatitis A vaccine antigen. For this reason,
3 doses of Twinrix must comprise the series. |
|
| Why does a 15-year old who weighs
160 lbs receive a pediatric dose of hepatitis A vaccine while his
110-pound mother receives an adult dose (twice the pediatric dose)? |
|
| The efficacy data from the clinical trials
were based on age at time of vaccination, and not on the weight of
the individual. Hence, the dosage recommendations reflect
this age-based efficacy data. The same holds true for hepatitis B vaccine. In
addition, higher response rates are expected in younger persons, even if their
weights are above the norm. |
|
|
|
|
|
|
| What is immune globulin (IG)? |
|
| IG is a sterile preparation of concentrated
antibodies (i.e., immunoglobulins) made from pooled human plasma processed
by cold ethanol fractionation. In the United States, only plasma that
has tested negative for hepatitis B surface antigen, antibody to human
immunodeficiency virus (HIV), and antibody to hepatitis C virus (HCV)
is used to produce IG. In addition, the Food and Drug Administration
requires that the process used to produce IG include a viral inactivation
step or that final products test negative for HCV-RNA by polymerase chain
reaction. Anti-HAV concentrations differ among IG lots, and decreasing
concentrations have been observed over the preceding 30 years, probably
because of the decreasing prevalence of previous HAV infection among
plasma donors; however, no clinical or epidemiologic evidence of decreased
protection has been observed. |
|
| How does IG work? |
|
| IG provides protection against HAV infection
through passive transfer of antibody. Depending on the IG dosage,
protection lasts from 3 to 5
months. When administered for preexposure prophylaxis, one dose of 0.02
mL/kg IM confers protection for less than 3 months, and one dose of 0.06
mL/kg IM confers protection for 3 to 5 months. When administered within
2 weeks after an exposure to HAV (0.02 mL/kg IM), IG is 80%-90% effective
in preventing HAV infection. Efficacy is greatest when IG is administered
early in the
post-exposure period. |
|
| How is IG packaged and how is IG administered? |
|
| IG is available in single-use (2 mL)
and multidose (10 mL) vials. For administration of IG, an appropriate
muscle mass (i.e., the deltoid
or gluteal muscle) should be chosen into which a substantial volume can
be injected, using a needle length appropriate for the person's age and
size. If a gluteal muscle is used, the central region of the buttock
should be avoided; only the upper outer quadrant should be used, and
the needle should be directed anteriorly to minimize the possibility
of injury to the sciatic nerve. |
|
| Does IG cause adverse events? |
|
| Serious adverse events from IG are rare.
Anaphylaxis has been reported after repeated administration to persons
with known immunoglobulin A
(IgA) deficiency; thus, IG should not be administered to these persons. |
|
| Can pregnant or lactating women receive
IG? |
|
| Yes. Pregnancy or lactation is not a
contraindication to IG administration. |
|
| What are the hepatitis A vaccination recommendations for
vaccination of travelers to protect them from HAV infection? |
|
| The recommendations (www.cdc.gov/mmwr/preview/mmwrhtml/mm5641a3.htm)
state that (1) hepatitis A vaccine is recommended for healthy
susceptible persons ages 1 through 40 years who travel to or work in
regions where hepatitis A is endemic and (2) hepatitis A vaccine should
be given as soon as travel is considered, but it can be given any time
prior to departure. For optimal protection in instances when departure
will take place within two weeks, persons older than age 40 years,
immunocompromised persons, and persons with diagnosed chronic liver
disease or other chronic medical conditions, should also receive IG
simultaneously with the first dose of hepatitis A vaccine but at a
different anatomic injection site. For travelers younger than age 1
year, IG alone is recommended because hepatitis A vaccine is not
licensed for use in this age group. Hepatitis A is endemic in all
regions except the United States, Western Europe, New Zealand,
Australia, Canada, and Japan. |
|
| We have an adult patient who received
the correct pediatric series of HepA vaccine as a teenager and is now
traveling abroad. Does the patient need an adult booster? |
|
| No. There is no recommendation for a
booster dose of hepatitis A vaccine if a patient has completed the
2-dose series at any age. |
|
| Is it really necessary to vaccinate
travelers to Latin America who will be staying in 4-star hotels? |
|
| Yes. Data have shown that persons acquire
HAV infection even in such places as 4-star hotels located in Latin
America. |
|
| If a traveler received the first dose
of hepatitis A vaccine more than one year ago and needs to travel
abroad imminently, will the traveler need IG in addition to dose
#2 prior to leaving? |
|
| No. Just give the final dose of hepatitis
A vaccine prior to travel. |
|
| If an infant younger than age 12 months
receives IG before travel to a hepatitis A endemic area, will he/she
need hepatitis A vaccine before another trip to a hepatitis A endemic
area? |
|
| Possibly. Since IG protects against HAV
infection for only 3 to 5 months, depending on the dosage given,
additional IG may be needed if the infant is not yet age
12 months. Once they have reached their first birthday, hepatitis A vaccine should
be given. |
|
| Can VFC-eligible children who travel
to HAV-endemic areas receive hepatitis A vaccine under the VFC
program? |
|
| Yes. Hepatitis A vaccine is covered under
VFC for eligible children for all indications
recommended by
ACIP, including travel to HAV-endemic areas. |
|
| If a person was born and grew up in
a country where HAV infection is endemic (e.g., Vietnam, Mexico)
and then moved to the United States at age 20, should that person
receive hepatitis A vaccine
before returning to visit his/her homeland? |
|
| It depends on whether that person has
a history of HAV infection. Unless there are medical records that
document prior HAV infection, serologic testing for
immunity (positive test for total anti-HAV) is the only way to determine if vaccination
is necessary. For persons from countries with high rates of HAV infection, such
as Vietnam and Mexico, serologic testing might be done to prevent unnecessary
vaccination. The cost effectiveness of serologic testing, however, should be
balanced against the possibility of delaying needed vaccination while awaiting
test results. |
|
| If a person has had HAV infection,
should they still receive the vaccine if planning international
travel? |
|
| No, as long as there are medical records
that document that the person was previously infected with HAV (i.e.,
positive test for total anti-HAV). If there is any doubt
that the person actually was infected with HAV, hepatitis A vaccine or IG should
be given. The vaccine or IG will not harm a person who is already immune. Refer
to the first question in this section for further information. |
|
| Reviewed on 10/09 by IAC staff |
|
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