What is hepatitis A?
Hepatitis A is a liver disease caused by hepatitis A virus.
Good personal hygiene and proper
sanitation can help prevent hepatitis A. Vaccines are also available for long-term
prevention of hepatitis A virus infection in persons 2 years of age and older. Immune
globulin is available for short-term prevention of hepatitis A virus infection in individuals of all ages.
How is hepatitis A virus transmitted?
Hepatitis A virus is spread from person to person by putting something in the mouth that
has been contaminated with the stool of a person with hepatitis A. This type of
transmission is called "fecal-oral." For this reason, the virus is more easily spread in
areas where there are poor sanitary conditions or where good personal hygiene is not
observed.
Most infections result from contact with a household member or sex partner who has
hepatitis A. Casual contact, as in the usual office, factory, or school setting, does
not spread the virus.
What are the signs and symptoms of
hepatitis A?
Persons with hepatitis A virus infection may not have any signs or symptoms of the
disease. Older persons are more likely to have symptoms than children. If symptoms are
present, they usually occur abruptly and may include fever, tiredness, loss of appetite,
nausea, abdominal discomfort, dark urine, and jaundice (yellowing of the skin and
eyes). Symptoms usually last less than 2 months; a few persons are ill for as long as 6
months. The average incubation period for hepatitis A is 28 days (range: 15–50 days).
How do you know if you have
hepatitis A?
A blood test (IgM anti-HAV) is needed to diagnose hepatitis A. Talk to your doctor or
someone from your local health department if you suspect that you have been exposed to
hepatitis A or any type of viral hepatitis.
How can you prevent hepatitis A?
Always wash your hands after using the bathroom, changing a diaper, or before preparing
or eating food.
Two products are used to prevent hepatitis A virus infection: immune globulin and
hepatitis A vaccine.
- Immune globulin is a preparation
of antibodies that can be given before exposure for short-term protection against
hepatitis A and for persons who have already been exposed to hepatitis A virus.
Immune globulin must be given within 2 weeks after exposure to hepatitis A virus for
maximum protection.
- Hepatitis A vaccine has been
licensed in the United States for use in persons 2 years of age and older. The
vaccine is recommended (before exposure to hepatitis A virus) for persons who are
more likely to get hepatitis A virus infection or are more likely to get seriously
ill if they do get hepatitis A. The vaccines currently licensed in the United
States are HAVRIX® (manufactured by GlaxoSmithKline) and VAQTA®
(manufactured by Merck & Co., Inc).
Who Should Get
Vaccinated Against Hepatitis A?
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HEPATITIS A
VACCINE AND IMMUNE GLOBULIN |
Hepatitis A Vaccine
What are the dosages and
schedules for hepatitis A vaccines?
Recommended dosages of HAVRIX®¹
|
Vaccinee's age
(years) |
Dose (EL.U.)² |
Volume (mL) |
No.
doses |
Schedule (mos)³ |
|
|
2-18 |
720 |
0.5 |
2 |
0,6-12 |
|
>18 |
1,440 |
1.0 |
2 |
0,6-12 |
|
| ¹ |
Hepatitis A vaccine, inactivated, GlaxoSmithKline. |
| ² |
ELISA units. |
| ³ |
0
months represents timing of the initial dose; subsequent numbers
represent months after the initial dose. |
|
Recommended dosages of
VAQTA®¹
|
Vaccinee's age
(years) |
Dose(U)² |
Volume (mL) |
No.
doses |
Schedule (mos)³ |
|
| 2-18 |
25 |
0.5 |
2 |
0,6-18 |
|
>18 |
50 |
1.0 |
2 |
0,6-12 |
|
| ¹ |
Hepatitis A vaccine, inactivated, Merck & Co., Inc. |
| ² |
Units. |
| ³ |
0
months represents timing of the initial dose; subsequent numbers
represent months after the initial dose. |
|
Can a patient receive the first dose of
hepatitis A vaccine from one manufacturer and the second (last) dose from another
manufacturer?
Yes. Although studies have not been done to look at this issue, there is no reason to
believe that this would be a problem.
What should be done if the
second (last) dose of hepatitis A vaccine is delayed?
The second dose
should be administered as soon as possible. There is no need to repeat the first dose.
Can other vaccines be given at the
same time that hepatitis A vaccine is given?
Yes. Hepatitis B, diphtheria, poliovirus (oral and inactivated), tetanus, oral typhoid,
cholera, Japanese encephalitis, rabies, yellow fever vaccine or immune globulin can be
given at the same time that hepatitis A vaccine is given, but at a different injection
site.
Is hepatitis A vaccine safe?
Yes, hepatitis A vaccine has an excellent safety profile. No serious adverse events
have been attributed definitively to hepatitis A vaccine. Soreness at the injection
site is the most frequently reported side effect.
Any adverse event suspected to be associated with hepatitis A vaccination should be
reported to the Vaccine Adverse Events Reporting System (VAERS).
VAERS forms can be obtained by calling 1-800-822-7967.
How are hepatitis A vaccines
made?
There is no live virus in hepatitis A vaccines. The virus is inactivated during
production of the vaccines, similar to Salk-type inactivated polio vaccine.
How long does hepatitis A
vaccine protect you?
Although data on long-term protection are limited, estimates based on modeling
techniques suggest that protection will last for at least 20 years.
When are persons protected after
receiving hepatitis A vaccine?
Protection against hepatitis A begins four weeks after the first dose of hepatitis A
vaccine.
Can hepatitis A vaccine be given
after exposure to hepatitis A virus?
No, hepatitis A vaccine is not licensed for use after exposure to hepatitis A virus. In
this situation, immune globulin should be used.
Should pre-vaccination testing
be done?
Pre-vaccination testing is done only in specific instances to control cost (e.g.,
persons who were likely to have had hepatitis A in the past). This includes persons who
were born in countries with high levels of hepatitis A virus infection, elderly
persons, and persons who have clotting factor disorders and may have received factor
concentrates in the past.
Should post-vaccination testing
be done?
No.
Can hepatitis A vaccine be
given during pregnancy or lactation?
We don't know for sure, but because vaccine is produced from inactivated hepatitis A
virus, the theoretical risk to the developing fetus is expected to be low. The risk
associated with vaccination, however, should be weighed against the risk for hepatitis A
in women who may be at high risk for exposure to hepatitis A virus.
Can hepatitis A vaccine be
given to immunocompromised persons? (e.g., persons on hemodialysis or persons with AIDS)
Yes.
What is Twinrix®?
It is a combined hepatitis
A and hepatitis B vaccine for use in persons aged 18 years and older. Primary
vaccination consists of three doses, given on a 0-, 1-, and 6-month schedule, the same
schedule as that used for hepatitis B vaccine alone.
Read more about
hepatitis A and hepatitis B vaccine schedules (external link)
Read more about
hepatitis B vaccine
Immune Globulin
What is immune
globulin?
Immune globulin is a preparation of antibodies that can be
given before exposure for short-term protection against hepatitis A and for persons who
have already been exposed to hepatitis A virus. Immune globulin must be given within 2
weeks after exposure to hepatitis A virus for maximum protection.
Is immune globulin safe?
Yes. No instance of transmission of HIV (the virus that causes AIDS) or other viruses
has been observed with the use of immune globulin administered by the intramuscular
route. Immune globulin can be administered during pregnancy and breast-feeding.
Is immune globulin in short supply?
Please
click here for immune
globulin status.
|
WHO SHOULD GET
VACCINATED AGAINST HEPATITIS A? |
Hepatitis A vaccination provides
protection before one is exposed to hepatitis A virus. Hepatitis A vaccination is
recommended for the following groups who are at increased risk for infection and for any
person wishing to obtain immunity.
Persons traveling to or working in
countries that have high or intermediate rates of hepatitis A.
All susceptible persons traveling to or working in countries that have
high or
intermediate rates of hepatitis A should be vaccinated or receive immune globulin
before traveling. Persons from developed countries who travel to developing countries
are at high risk for hepatitis A. Such persons include tourists, military personnel,
missionaries, and others who work or study abroad in countries that have high or
intermediate levels of hepatitis A. The risk for hepatitis A exists even for travelers
to urban areas, those who stay in luxury hotels, and those who report that they have
good hygiene and that they are careful about what they drink and eat.
Children in states, counties, and
communities where rates of hepatitis A were/are at least twice the national average
during the baseline period of 1987-1997.
Children living in states, counties, and communities where rates
of hepatitis A are at least twice the national average ( ≥ 20 cases/1000,000) in
baseline period should be routinely vaccinated beginning at 2 years of age. High rates
of hepatitis A have been found in these populations, both in urban and rural settings.
In addition, to effectively prevent epidemics of hepatitis A, vaccination of previously
unvaccinated older children is recommended within 5 years of initiation of routine
childhood vaccination programs. Although rates differ among areas, available data
indicate that a reasonable cutoff age in many areas is 10-15 years of age because older
persons have often already had hepatitis A. Vaccination of children before they enter
school should receive highest priority, followed by vaccination of older children who
have not been vaccinated.
Men who have sex with men
Sexually active men
(both adolescents and adults) who have sex with men should be vaccinated.
Hepatitis A outbreaks among men who
have sex with men have been reported frequently. Recent outbreaks have occurred in urban
areas in the United States, Canada, and Australia.
Illegal-drug users
Vaccination is
recommended for injecting and non-injecting illegal-drug users.
Persons who have occupational risk
for infection
Persons who work with
hepatitis A virus-infected primates or with hepatitis A virus in a research laboratory
setting should be vaccinated. No other groups have been shown to be at increased risk
for hepatitis A virus infection because of occupational exposure.
Outbreaks of hepatitis A have been
reported among persons working with non-human primates that are susceptible to hepatitis
A virus infection, including several Old World and New World species. Primates that were
infected were those that had been born in the wild, not those that had been born and
raised in captivity.
Persons who have chronic liver
disease
Persons with chronic
liver disease who have never had hepatitis A should be vaccinated, as there is a higher
rate of fulminant (rapid onset of liver failure, often leading to death) hepatitis A
among persons with chronic liver disease. Persons who are either awaiting or have
received liver transplants also should be vaccinated.
Persons who have clotting-factor
disorders
Persons who have
never had hepatitis A and who are administered clotting-factor concentrates, especially
solvent detergent-treated preparations, should be given hepatitis A vaccine.
All persons with hemophilia (Factor
VIII, Factor IX) who receive replacement therapy should be vaccinated because there
appears to be an increased risk of transmission from clotting-factor concentrates that
are not heat inactivated.
|
WHICH GROUPS
DO NOT ROUTINELY NEED HEPATITIS A VACCINE? |
Food service workers
Foodborne hepatitis A outbreaks are relatively uncommon in the United States; however,
when they occur, intensive public health efforts are required for their control.
Although persons who work as food
handlers have a critical role in common-source foodborne outbreaks, they are not at
increased risk for hepatitis A because of their occupation. Consideration may be given
to vaccination of employees who work in areas where community-wide outbreaks are
occurring and where state and local health authorities or private employers determine
that such vaccination is cost-effective.
Sewerage workers
In the United States, no work-related outbreaks of hepatitis A have been reported among
workers exposed to sewage.
Health-care workers
Health-care workers are not at increased risk for hepatitis A. If a patient with
hepatitis A is admitted to the hospital, routine infection control precautions will
prevent transmission to hospital staff.
Children under 2 years of age
Because of the limited experience with hepatitis A vaccination among children under 2
years of age, the vaccine is not currently licensed for this age-group.
Day-care attendees
The frequency of outbreaks
of hepatitis A is not high enough in this setting to warrant routine hepatitis A
vaccination. In some communities, however, day-care centers play a role in sustaining
community-wide outbreaks. In this situation, consideration should be given to adding
hepatitis A vaccine to the prevention plan for children and staff in the involved
center(s).
Residents of institutions for
developmentally disabled persons
Historically, hepatitis A virus infections were common
among persons with developmental disabilities living in institutions. Currently, the
occurrence of hepatitis A virus infections have diminished.
Who should receive protection against
hepatitis A before travel?
All susceptible persons traveling to or working in countries that have high or
intermediate rates of hepatitis A should be vaccinated or receive immune globulin before
traveling. Persons from developed countries who travel to developing countries are at
high risk for hepatitis A. Such persons include tourists, military personnel,
missionaries, and others who work or study abroad in countries that have high or
intermediate levels of hepatitis A. The risk for hepatitis A exists even for travelers
to urban areas, those who stay in luxury hotels, and those who report that they have
good hygiene and that they are careful about what they drink and eat.
How soon before travel should the
first dose of hepatitis A vaccine be given?
For optimal protection, at least 4 weeks prior to travel. Check with your doctor
about when the next dose is due.
What should be done if a person
cannot receive hepatitis A vaccine?
Travelers who are allergic to a vaccine component or who elect not to receive vaccine
should receive a single dose of immune globulin (0.02 mL/kg), which provides effective
protection against hepatitis A virus infection for up to 3 months. Travelers whose
travel period exceeds 2 months should be administered immune globulin at 0.06 mL/kg;
administration must be repeated if the travel period exceeds 5 months.
If travel starts sooner than 4
weeks prior to the first vaccine dose, what should be done?
Because protection might not be optimal until 4 weeks after vaccination, persons
traveling to a
high-risk area less than 4 weeks after the initial dose of hepatitis A vaccine
should also be given immune globulin (0.02 mL/kg), but at a different injection site.
Therefore, the first dose of hepatitis A vaccine should be administered as soon as
travel to a high-risk area is planned.
What should be done for travelers
who are less than 2 years of age to protect them from hepatitis A virus infection?
Immune globulin is recommended for travelers less than 2 years of age because the
vaccine is currently not licensed for use in this age group.
Source:
MMWR:
Prevention of Hepatitis A Through Active or
Passive Immunization
The use of commercial sources and trade
names is for identification and does not imply endorsement by the Public Health Service or
the U.S. Department of Health and Human Services.
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Hepatitis A General
Information
