What is hepatitis A?
Hepatitis A is a liver disease caused by hepatitis A virus.
What are the
signs and symptoms of hepatitis A?
Persons with the hepatitis A virus 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; some
people are ill for as long as 6 months. The average incubation period for hepatitis A is
28 days (range: 15–50 days).
How is hepatitis A diagnosed?
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 is hepatitis A
transmitted?
The 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 office, factory, or a
school setting, does not spread the virus.
What products are
available to prevent hepatitis A virus infection?
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 the hepatitis A virus. Immune globulin must be given
within 2 weeks after exposure to hepatitis A 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 a hepatitis A virus infection
or are more likely to get seriously ill if they do get hepatitis A. The vaccines
that are currently licensed in the United States are HAVRIX(®) (manufactured by
SmithKline Beecham Biologicals) and VAQTA(®) (manufactured by Merck & Co., Inc).
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?
Yes. This shortage is expected to continue
necessitating a prioritization of indications for the use of immune globulin.
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.
How long does immunity last
after hepatitis A vaccination?
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. Check with your doctor for when the next dose
is due.
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 prevaccination
testing be done?
Prevaccination 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 postvaccination
testing be done?
No.
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
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 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.
PERSONS WHO SHOULD RECEIVE
HEPATITIS A VACCINE
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 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 communities that have
high rates of hepatitis A and periodic hepatitis A outbreaks.
Children living in communities that have high rates of
hepatitis A (e.g., American Indian, Alaska Native) should be routinely vaccinated
beginning at 2 years of age. High rates of hepatitis A are generally found in these
populations, both in urban and rural settings. In addition, to effectively
prevent epidemics of hepatitis A in these communities, 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
noninjecting illegal-drug users if local health authorities have noted current or past
outbreaks among such persons.
During the past decade, outbreaks have been reported among
injecting-drug users in the United States and in Europe.
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.
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.
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