Transcript Strategies of Vaccination against Hepatitis A in South Europe

The new Italian guidelines
for the use of
hepatitis A vaccine
Elisabetta Franco
Dept. of Public Health
University of Rome Tor Vergata - Italy
Consequences of the change in
epidemiology (improved socioeconomic/hygiene conditions)
Exposure
in early life
Proportion of
susceptibles
among older
children & adults
+
Proportion of
symptomatic disease
with age
Risk
for
clinically
significant
OUTBREAKS
WHO RECOMMENDATIONS
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In highly endemic countries most persons are
asymptomatically infected with HAV in
childhood, which effectively prevents clinical
hepatitis A in adolescents and adults. In
these countries large scale programs are not
recommended.
In countries of intermediate endemicity
where much of the population is susceptible
and hepatitis A represents a health burden,
large scale vaccination may be considered as
a supplement to education and sanitation.
WHO RECOMMENDATIONS
•
In regions of low endemicity, vaccination
against HAV is recommended for
individuals with increased risk of infection.
•
Epidemiological and cost benefit studies
should be considered before deciding on
national policies concerning immunization.
Wkly Epidemiol Rev 2000 5:38-44
• Documento di indirizzo: L'uso del
vaccino anti epatite A in Italia
• Sicurezza, efficacia, indicazioni
d'impiego nei gruppi a rischio e in
caso di epidemia
Maggio 2002
WHY?
The paper contains the evidence available
in literature and the expert opinions on
the possible use of the vaccine, in the
attempt to assist public health doctors
and clinicians in controlling HAV infection
and in counselling of patients and
contacts.
METHODS
• Individuation of a multidisciplinary team of experts
to address clinic and organization questions
• Research of scientific evidences from literature in
database as Medline, Embase, The Cochrane
Controlled Trial Register
• Evaluation of papers obtained from literature search
• Selection and evaluation of pertinent evidences
• Synthesis of conclusive data
• Conversion of evidences into recommendations
CONTENTS
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The Guidelines include:
Epidemiology of HAV infection in Italy
A systematic review of the effectiveness and
safety of vaccine
An economic evaluation for the use of the
vaccine
A systematic review of risk groups
A systematic review of measures in course of
outbreaks
A systematic review of post-exposure
prophylaxis
A synthesis of the main evidences
EFFECTIVENESS AND
SAFETY OF VACCINE
Seven papers have been obtained by
systematic review.
The effectiveness of vaccine was 86% in
pre exposure and 82% in post exposure
prophylaxis.
No important adverse reactions have been
reported.
ECONOMIC EVALUATION
From the economic point of view
mass vaccination is convenient only
in course of outbreaks, while the
vaccination of the contacts of
acute hepatitis A cases should be
used as a routine measure.
RISK GROUPS for
Hepatitis A virus infection
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Travelers
Military Personnel
Health Care Workers
Sewage Workers
Food Handlers
Day Care Centers
Institutions
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Transfusion
Hemophilia
Drug Addicts
Homosexual
Prisoners
HIV
Transplantation
TRAVELERS
Evidences about the risk of acquiring hepatitis A
essentially date back to studies performed in the
eighties and early nineties; however, despite the
improvement of socio-economic level, travels are
still considered a risk factor, with a gradation
dependent on the endemicity of visited areas and
on the observance of hygiene preventive measures
HEALTH CARE WORKERS
On the basis of the documented effectiveness of
the universal precaution measures in protecting
against HAV occupational exposure a group, in
which there is no evidence of higher antibody
seroprevalence than in the general population,
there is no evidence that health care workers
constitute a risk group for HAV infection.
SEWAGE WORKERS
There is evidence that sewage workers are
exposed to a higher personal risk related to the
profession, even observing adequate hygienic
precautions.
However they do not represent a risk for the
community and no epidemics are reported where
they represented the infection source.
FOOD HANDLERS
Food handlers
can
contract
HAV
from
contaminated food, and, once infected, they
may be the source of infection. There are,
however, no evidences to consider food handlers
as a risk group and the contamination of food
by infected food handlers or the infection by
contaminated food manipulation are easily
avoidable by observing the most common and
basic hygienic norms.
DAY CARE PERSONNEL
In day care centre not only children, but also
family members and personnel are at risk for
HAV infection. For both groups the risk is
related to close contact with children and is
greater within the family as in personnel it can
be easily avoided observing the generally
adopted standard hygienic measures.
There are therefore no strong evidences for
considering personnel of day care centres as a
risk group for HAV.
INSTITUTIONALIZED PERSONS
Outbreaks of hepatitis A in institutions for
subjects with physical and, above all, mental
handicaps have been described in which the age
of residents and the length of stay were related
to the risk of acquiring HAV and a higher
antibody
prevalence
was
detected
among
patients.
There is evidence of risk of contracting hepatitis
A among institutionalised subjects while staff
members may easily protect themselves from
exposure to HAV.
HAEMOPHILIA PATIENTS
Hepatitis A outbreaks among haemophiliacs treated
with S/D inactivated factors VIII/IX concentrates
have been described in the past, but in the last
years no more cases of HAV infection have been
reported, due to the improved inactivation methods
and the use of products obtained through genetic
recombination techniques.
Seroprevalence and case-control studies do not
show an increased risk of
hepatitis A among
haemophiliacs.
DRUG ADDICTS
Epidemics that happen regularly among drug addicts
and homosexual men have been described and it is
pointed out that these groups may become important
sources of hepatitis A, even if drug addicts are not
recognised as sources of epidemics in the general
population. Hepatitis A prevalence is slightly higher in
drug addicts than in various control populations; the
transmission is connected to socio-economic factors,
sexual
promiscuity,
syringe
exchange
and
contamination of instruments used to prepare drug.
SEXUAL PROMISCUITY
The hypothesis of considering homosexuals as a
potential group at risk of acquiring HAV dates
back to the early Nineties and arises from the
demonstration of a peak incidence of hepatitis A
in males aged 20 – 39 and the description of
many outbreaks among homosexuals.
The risk of acquiring HAV infection is linked to
oro–anal sexual practices and sexual promiscuity.
Prevalence studies do not show significant
differences in anti-HAV prevalence between
homosexuals and control groups.
PATIENTS WITH CHRONIC
LIVER DISEASE
Even if not all the examined papers are of
high quality, from the systematic review it
results that these patients show a greater
risk of complications.
The vaccination is recommended to patients
with an advanced chronic liver disease.
OUTBREAKS
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In closed communities, like day care centers,
where most subjects are susceptible and the
risk for person to person transmission is
high, vaccine is recommended for family
members, school mates and personnel after a
single case.
In older age groups, vaccination is
recommended if a secondary case is
demonstrated.
OUTBREAKS
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In small open communities, like small towns
(less than 5.000 inhabitants), vaccination is
recommended to more susceptible age groups
like children and adolescents.
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This intervention is effective if coverage is
more than 80% of the target population.
OUTBREAKS
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In large communities with high interepidemic
incidence and periodic outbreaks mass
vaccination cannot be offered due to the
difficulty of reaching high coverage in a
short time. Vaccine should be offered to
contacts of acute cases, combined with the
improvement of sanitation.
POST-EXPOSURE
PROPHYLAXIS
There is only a recent trial about the
effectiveness of vaccine as post-exposure
prophylaxis (82%).
The vaccine administered not later than 8
days since the exposure is preferred to the
use of gamma-globulins.
IN CONCLUSION
Although the proposed recommendations
are meant for the Italian epidemiological
context, the evidence and the discussion
presented in the Guide Lines are useful
materials for implementing vaccination
against hepatitis A in other western
countries.