Hepatitis A vaccination
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the dis |
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fatality ratio is low but is greater in older patients
and those with pre-existing
liver disease. There is no chronic carrier state and
chronic liver damage does
not occur.
The virus is usually transmitted by the faecal–oral
route through person-toperson spread or contaminated food or drink. Foodborne
outbreaks have been
reported following ingestion of certain shellfish
(bivalve molluscs such as
mussels, oysters and clams that feed by filtering large
volumes of sewagepolluted waters) and salad vegetables. Transmission of
hepatitis A has been
associated with the use of factor VIII and factor IX
concentrates where viral
inactivation procedures did not destroy hepatitis A
virus. The incubation period
is usually around 28–30 days but may occasionally be as
little as 15 or as much
as 50 days
the hepatitis A vaccination
There are two products for immunisation
against hepatitis A. An
immunoglobulin provides rapid but temporary immunity.
The vaccine confers
active immunity but response is not immediate. Vaccines
are available as either
monovalent, or combined with either typhoid or
hepatitis B.
Hepatitis A monovalent vaccines and those combined with
either typhoid
or hepatitis B do not contain thiomersal. The vaccines
are inactivated, do not
contain live organisms and cannot cause the diseases
against which they protect.
Human normal immunoglobulin
Human normal immunoglobulin (HNIG) is
prepared from pooled plasma
derived from blood donations. Use of HNIG should be
limited to situations
where it may have a definite advantage over vaccine.
HNIG can provide
immediate protection, although antibody levels are lower
than those eventually
produced by hepatitis A vaccine. There have been no
studies directly
comparing the efficacy of HNIG with vaccine for
prophylaxis in contacts of
cases. HNIG licensed for use for prophylaxis must have
a hepatitis A antibody
level of at least 100IU/ml.
Storage
Vaccines should be stored in the original
packaging at +2°C to +8°C and
protected from light. All vaccines are sensitive to
some extent to heat and cold.
Heat speeds up the decline in potency of most vaccines,
thus reducing their
shelf life. Effectiveness cannot be guaranteed for
vaccines unless they have
been stored at the correct temperature. Freezing may
cause increased
reactogenicity and loss of potency for some vaccines.
It can also cause hairline
cracks in the container, leading to contamination of
the contents.
HNIG should be stored in the original packaging in a
refrigerator at +2°C
to +8°C. These products are tolerant to higher ambient
temperatures for
up to one week. They can be distributed in sturdy
packaging outside the cold
chain, if needed
Dosage and schedule
The immunisation regimes for hepatitis A
vaccine and for combined hepatitis
A and typhoid vaccine consist of a single dose. The standard
schedule for the
combined hepatitis A and hepatitis B vaccine depends on
the product. For
Twinrix® the schedule consists of
three doses, the first on the elected date, the
second one month later and the third six months after
the first dose. For
Ambirix® the schedule consists of two
doses, the first administered on the
elected date and the second between six and twelve
months after the first dose.
Hepatitis A
Hepatitis
A
An accelerated schedule of Twinrix Adult® at 0,
7 and 21 days may be used
when early protection against hepatitis B is required
(e.g. for travellers
departing within one month).
dosage for monovalent hepatitis A immunization
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Vaccine product |
Ages |
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Havrix Monodose® 16
years or over |
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Havrix Junior |
One to 15 years |
Dose Volume
Dosage of combined hepatitis A and typhoid vaccines
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Vaccine |
Ages |
Dose HAV |
Dose Vi P ty |
Volume |
|
product |
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Hepatyrix® |
15 years |
1440 ELISA units |
25µg |
1.0ml |
|
or over |
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ViATIM® |
16 years |
160 antigen units |
25µg |
1.0ml |
|
or over |
Dosage of combined hepatitis A and hepatitis b vaccines
Vaccine Ages Dose HAV Dose HbV Volume
product
Twinrix 16 years 720 ELISA units 20µg 1.0ml
Adult® or over
Twinrix 1 to 15 years 360 ELISA units 10µg 0.5ml
Paediatric®
Ambirix® 1 to 15 years 720 ELISA units
20µg 1.0ml
Dosage
of HNiG
● 250mg for children under ten
years.
●
500mg for those aged ten years or older.
Administration
Vaccines are routinely given into the upper
arm or anterolateral thigh.
However, for individuals with a bleeding disorder,
vaccines should be given by
deep subcutaneous injection to reduce the risk of
bleeding.
Hepatitis A-containing vaccines can be given
at the same time as other
vaccines such as hepatitis B, MMR, MenC, Td/IPV and
other travel vaccines.
The vaccines should be given at a separate site,
preferably in a different limb.
If given in the same limb, they should be given at
least 2.5cm apart (American
Academy of Pediatrics, 2003). The site at which each
vaccine was given should
be noted in the individual’s records.
HNIG can be administered in the upper outer quadrant of
the buttock or
anterolateral thigh . If more than 3ml
is to be given to young
children and infants, or more than 5ml to older
children and adults, the
immunoglobulin should be divided into smaller amounts
and administered at
different sites. HNIG may be administered, at a
different site, at the same time
as hepatitis A vaccine.
Recommendations for the use of the vaccine
Pre-exposure vaccination
The objective of the immunisation programme
is to provide two doses of a
hepatitis A-containing vaccine at appropriate intervals
for all individuals at
high risk of exposure to the virus or of complications
from the disease.
Groups
recommended to receive pre-exposure vaccination
People travelling to or going to reside in
areas of high or
intermediate prevalence
Immunisation with hepatitis A vaccine is
recommended for those aged one
year and over travelling to areas of moderate or high
endemicity, such as the
Indian subcontinent, for prolonged periods,
particularly if sanitation and food
hygiene is likely to be poor. Vaccine is also
recommended for all individuals
going to reside in or likely to be posted for long
periods to hepatitis A
virus-endemic countries.
Although hepatitis A is usually sub-clinical in
children, it can be severe and
require hospitalisation. Even children who acquire mild
or sub-clinical
hepatitis A may be a source of infection to others. The
risks of disease for
children under one year old are low, and vaccines are
not licensed for their use
Hat this age. Care should be taken to prevent
exposure to hepatitis A infection
through food and water.
For travellers, vaccine should preferably be given at
least two weeks before
departure, but can be given up to the day of departure.
Although antibodies
may not be detectable for 12–15 days following
administration of monovalent
hepatitis A vaccine, the vaccine may provide some
protection before antibodies
can be detected using current assays.
Immunisation is not considered necessary for
individuals travelling to or going
to reside in Northern or Western Europe (including
Spain, Portugal and Italy),
or North America, Australia or New Zealand. HNIG is no
longer recommended
for travel prophylaxis. Country-by-country
recommendations for hepatitis A
and other travel vaccines are given in Health information for overseas travel
(www.nathnac.org).
Patients with chronic liver disease
Although patients with chronic liver disease
may be at no greater risk of
acquiring hepatitis A infection, it can produce a more
serious illness in these
patients (Akriviadis and Redeker, 1989; Keefe, 1995).
Immunisation against
hepatitis A is therefore recommended for patients with
severe liver disease of
whatever cause. Vaccine should also be considered for
individuals with chronic
hepatitis B or C infection and for those with milder
forms of liver disease.
Patients with haemophilia
As standard viral inactivation processes may
not be effective against hepatitis
A, patients with haemophilia who are receiving
plasma-derived clotting factors
should be immunised against hepatitis A. Patients with
haemophilia should be
immunised subcutaneously.
Men who have sex with men
MSM with multiple sexual partners need to be
informed about the risks of
hepatitis A, and about the need to maintain high
standards of personal hygiene.
Immunisation should be offered to such individuals,
particularly during
periods when outbreaks are occurring.
Injecting drug users
Hepatitis A immunisation is recommended for
injecting drug users and can be
given at the same time as hepatitis B vaccine, as
separate or combined
preparations.
Individuals at occupational risk
Hepatitis A vaccination is recommended for
the following groups:
●
laboratory
workers: individuals who may be exposed
to hepatitis A in
the course of their work, in microbiology laboratories
and clinical
infectious disease units, are at risk and must be
protected.
●
staff of some
large residential institutions: outbreaks
of hepatitis A
have been associated with large residential
institutions for those with
learning difficulties. Transmission can occur more
readily in such
institutions and immunisation of staff and residents is
appropriate.
Similar considerations apply in other institutions
where standards of
personal hygiene among clients or patients may be poor.
●
sewage
workers: raw, untreated sewage is
frequently contaminated with
hepatitis A. A UK study to evaluate this risk showed
that frequent
occupational exposure to raw sewage was an independent
risk factor for
hepatitis A infection (Brugha et al., 1998). Immunisation
is, therefore,
recommended for workers at risk of repeated exposure to
raw sewage,
who should be identified following a local risk
assessment.
●
people who
work with primates: vaccination is
recommended for those
who work with primates that are susceptible to
hepatitis A infection.
Hepatitis A vaccination may be considered under certain
circumstances for:
●
food
packagers and handlers: food packagers or
food handlers in the
UK have not been associated with transmission of
hepatitis A sufficiently
often to justify their immunisation as a routine
measure. Where a case
or outbreak occurs, advice should be sought from the
local health
protection unit (HPU)
●
staff in
day-care facilities: infection in young
children is likely to be
sub-clinical, and those working in day-care centres and
other settings
with children who are not yet toilet trained may be at
increased risk
(Severo et al., 1997). Under normal circumstances, the risk of
transmission to staff and children can be minimised by
careful attention
to personal hygiene. However, in the case of a
well-defined community
outbreak, such as in a pre-school nursery, the need for
immunisation of
staff and children should be discussed with the local
HPU
●
healthcare
workers: most healthcare workers are not
at increased risk
of hepatitis A and routine immunisation is not
indicated.
Post-exposure
immunisation
Either passive or active immunisation, or a
combination of the two, is
available for the management of contacts of cases and
for outbreak control.
Hepatitis
There have been no trials directly comparing
the efficacy of hepatitis A
vaccine alone against HNIG in the management of
contacts. HNIG is
preferred when protection is required in a shorter time
than it takes for a
protective antibody response to the vaccine. Vaccine
and HNIG may be given
at the same time, but in different sites, when both
rapid and prolonged
protection is required. A single dose of monovalent
hepatitis A vaccine will
provide more rapid protection than the combined
preparations where more
than one dose is required.
HNIG has a proven record in providing prophylaxis for
contacts of cases of
acute hepatitis A. HNIG will protect against hepatitis
A infection if administered
within 14 days of exposure, and may modify disease if
given after that time
(Winokur and Stapleton, 1992). Protection lasts for
four to six months.
There is some evidence that vaccine may be effective in
preventing infection
in contacts of cases, provided it can be given soon
enough after the onset of
symptoms in the index case. A study in Naples
(Sagliocca et al., 1999) showed
hepatitis A vaccine had a 79% protective efficacy in
household contacts of
people with sporadic infection, where 56% of contacts
received vaccine within
four days of onset of symptoms in the index cases, and
all within eight days.
If vaccine is to be used in preference to HNIG for
prophylaxis of contacts,
cases of acute hepatitis A will need to be diagnosed
and reported to public
health officials quickly enough to allow administration
of vaccine within one
week of onset.
Contacts
of cases of hepatitis A infection
Hepatitis A vaccine should be given to
previously unvaccinated contacts of
cases of hepatitis A with onset of jaundice within the
last week. When the
interval is longer, HNIG should be used, particularly
for older people, given the
greater severity of disease in this age group. Further
guidance on the
management of contacts is available in ‘Guidelines for
the control of hepatitis
A virus infection’ (Crowcroft et al., 2001).
Prophylaxis restricted to household and close contacts
may be relatively
ineffective in controlling further spread. If given to
a wider social group of
recent household visitors (kissing contacts and those
who have eaten food
prepared by an index case), spread may be prevented
more effectively.
If a food handler develops acute jaundice or is
diagnosed clinically or
serologically with hepatitis A infection, the local HPU
should be immediately
informed by telephone. This will allow a timely risk
assessment of whether
other food handlers in the same food
preparation area could have been exposed
and should be considered for post-exposure prophylaxis.
Rapid serological
confirmation and notification of hepatitis A infection
will allow an assessment
of the possible risks to any customers who can be
traced and offered prophylaxis.
Further prophylaxis will not be required in
immunocompetent contacts who
have previously received hepatitis A vaccine.
If a contact is at ongoing risk of hepatitis A
infection because of their lifestyle
or any other reason, then they should be offered
vaccine irrespective of
whether they are offered HNIG.
Primary
immunisation
The primary immunisation course for
hepatitis A vaccine and for combined
Hepatitis A and typhoid vaccine consists of a single
dose. For adult combined
hepatitis A and B vaccines (Twinrix®) a
primary course consists of three doses.
There are two combined hepatitis A and B vaccines
suitable for use in children.
A primary course of Twinrix consists of three doses,
whereas Ambirix®
consists of two doses at a longer interval. The
first dose of Ambirix®, however,
provides equivalent protection to a primary course of
single hepatitis A
vaccine, although protection against hepatitis B is not
complete until after the
second dose. Protection from a primary course of single
or combined vaccines
lasts for at least one year.
Reinforcing
immunisation
A booster dose of hepatitis A vaccine should
be given at six to 12 months after
the initial dose. This results in a substantial
increase in the antibody titre and
will give immunity beyond ten years. Until further
evidence is available on
Hpersistence of protective immunity, a
further booster at 20 years is indicated
for those at ongoing risk (Van Damme, 2003).
Where a combined hepatitis A and typhoid vaccine has
been used to initiate
immunisation, a dose of single antigen hepatitis A
vaccine will be required six
to 12 months later in order to provide prolonged
protection against hepatitis A
infection. Booster doses of the typhoid component will
be required at three
years.
For individuals who have received combined hepatitis A
and B vaccine in an
accelerated schedule, a booster dose is required at one
year.
Delayed
administration of the booster dose
Ideally, the manufacturers’ recommended
timing for the administration of the
booster dose of hepatitis A vaccine should be followed.
In practice, and
particularly in infrequent travellers, there may be a
delay in accessing this
injection. Studies have shown that successful boosting
can occur even when
the second dose is delayed for several years (Landry et al., 2001; Beck et al.,
2003), so a course does not need to be re-started.
Contraindications
There are very few individuals who cannot
receive hepatitis A-containing
vaccines. When there is doubt, appropriate advice
should be sought from a
consultant paediatrician, immunisation co-ordinator or
local HPU rather than
withholding vaccine.
The vaccine should not be given to those who have had:
●
a confirmed anaphylactic reaction to a
previous dose of a hepatitis
A-containing vaccine, or
●
a confirmed anaphylactic reaction to any
component of the vaccine.
Epaxal should not be given to those who have had a
confirmed anaphylactic
hypersensitivity to egg products as a component of the
vaccine is prepared on
hens’ eggs.
Precautions
Minor illnesses without fever or systemic
upset are not valid reasons to
postpone immunisation.
If an individual is acutely unwell, immunisation may be
postponed until they
have fully recovered. This is to avoid
confusing the differential diagnosis of
any acute illness by wrongly attributing any signs or
symptoms to the adverse
effects of the vaccine.
HNiG
When HNIG is being used for prevention of
hepatitis A, it must be remembered
that it may interfere with the subsequent development
of active immunity from
live virus vaccines. If immunoglobulin has been
administered first, then an
interval of three months should be observed before
administering a live virus
vaccine. If immunoglobulin has been given within three
weeks of administering
a live vaccine, then the vaccine should be repeated
three months later. This
does not apply to yellow fever vaccine since HNIG does
not contain significant
amounts of antibodies to this virus.
Pregnancy
and breast-feeding
Hepatitis A-containing vaccines may be given
to pregnant women when
clinically indicated. There is no evidence of risk from
vaccinating pregnant
women or those who are breast-feeding with inactivated
viral or bacterial
vaccines or toxoids (Plotkin and Orenstein, 2004).
immunosuppression
and HiV infection
Individuals with immunosuppression and HIV
infection can be given hepatitis
A-containing vaccines (Bodsworth et al., 1997; Kemper et al., 2003) although
seroconversion rates and antibody titre may be lower
and appear to be related
to the individual’s CD4 count at the time of
immunisation (Neilsen et al., 1997;
Kemper et al., 2003). Re-immunisation should be considered and specialist
advice may be required.
Adverse reactions
Adverse reactions to hepatitis A vaccines
are usually mild and confined to the
first few days after immunisation. The most common
reactions are mild,
transient soreness, erythema and induration at the
injection site. A small,
painless nodule may form at the injection site; this
usually disappears and is of
no consequence.
Hepatitis
General symptoms such as fever, malaise,
fatigue, headache, nausea and loss
of appetite are also reported less frequently.
HNIG is well tolerated. Very rarely, anaphylactoid
reactions occur in
individuals with hypogammaglobulinaemia who have IgA
antibodies, or those
who have had an atypical reaction to blood transfusion.
Serious, suspected adverse reactions to vaccines should
be reported through
the Yellow Card scheme.
No cases of blood-borne infection acquired through
immunoglobulin
preparations designed for intramuscular use have been
documented in any
country.
Supplies
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