Archive Number: 20020621.4560
Published Date: 21-JUN-2002
Subject: PRO> Smallpox vaccine, ACIP recommendations - USA (02)
SMALLPOX VACCINE, ACIP RECOMMENDATIONS - USA (02)
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A ProMED-mail post
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International Society for Infectious Diseases
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Date: Fri, 21 Jun 2002 00:18:59 -0400
From: Stephen M. Apatow <s.m.apatow@humanitarian.net>
Re: Smallpox vaccine, ACIP recommendations - USA: June 20, 2002
---------------------------------
The ACIP projections of 300 fatalities that would occur as a result of
side
effects if the whole nation were vaccinated against smallpox is a gross
understatement that deserves discussion.
The topic if bioterrorism, in the context of Smallpox, vaccination and
HIV
presents a serious challenge for the public health community
worldwide. According to the World Health Organization, immunization
with
the smallpox vaccine -- made from a live weakened virus -- would now be
fatal for many people whose immune system is impaired by HIV [1].
Therefore, vaccination would be contraindicated for certain groups that
include persons with immune disorders or those experiencing
therapeutically-induced immunosuppression, persons with HIV infection,
and
persons with a history of eczema [2].
According to Anthony S. Fauci, M.D, as the AIDS epidemic enters its third
decade, more than 900 000 individuals are living with HIV infection in
the
United States and another 460 000 HIV-infected people in this country have
died. An additional 40 000 Americans will become newly infected with HIV
this year. More than half of these infections will occur in young people
under age 25. Around the world the situation is much worse: 40 million
people are living with HIV/AIDS, and 22 million HIV-infected individuals
have already died [3].
HIV and smallpox vaccination present a significant challenge to the
statistical equation. Unlike other emerging infectious diseases, there
is
not a public health mandate for HIV testing combined with contact tracing
for known at-risk contacts. Therefore, the presence of hidden HIV
infection in a population base presents a new dimension of issues that
would arise from this variable combined with associated contraindications
for vaccination in a bioterrorist incident.
1. WHO Infectious Diseases Report, Chapter 7 text.
<http://www.who.int/infectious-disease-report/pages/ch7text.html>
2. WHO Fact Sheet on Smallpox, Contraindications, October 2001.
<http://www.who.int/emc/diseases/smallpox/factsheet.html>
3. Fauci, Director, National Institute of Allergy and Infectious Diseases,
National Institutes of Health, HIV Vaccine Awareness Day, May 18, 2002.
<http://www.niaid.nih.gov/newsroom/mayday/faucimessage.htm>
--
Stephen M. Apatow
Humanitarian Resource Institute
Biodefense Reference Library
<http://www.humanitarian.net/biodefense>
<s.m.apatow@humanitarian.net>
[Stephen Apatow's concerns are very well stated above. We do not
have an
adequate analysis of the potential risk in today's environment, which
includes many immunocompromised hosts leading mainstream lives who are
at
risk of casual exposure to wild virus and vaccine virus.
Kemper et al. did a "Back of the Envelope" presentation of possible risks
associated with smallpox vaccination for the Effective Clinical Practice,
March/April 2002 issue for the American College of Physicians (ACP)
journal. They concluded: "After excluding high-risk individuals and their
contacts, we estimate that a vaccination strategy directed at people aged
1
to 29 years would result in approximately 1600 serious adverse events and
190 deaths. Vaccinating people aged 1 to 65 years would result in
approximately 4600 serious adverse events and 285 deaths. Limitations:
While advances in health care over the past 3 decades could mitigate
vaccine complications, the increased number of unimmunized high-risk
individuals (e.g., those with eczema or immune suppression) could increase
complication rates."
They then went on to discuss the limitations and additional dangers to
"high-risk" individuals of a mass immunization campaign. "We assumed
that
individuals would be screened before vaccination for risk factors, such
as
eczema, immunodeficiency, or pregnancy, in themselves or in their close
contacts. The prevalence of eczema and the number of immunocompromised
individuals have increased over the past 3 decades. High-risk populations
would be excluded from vaccination, as would their potential contacts,
since recent vaccine recipients are "infectious" and can transmit the virus
(vaccinia).
Individuals with eczema are at high risk for developing eczema vaccinatum.
The prevalence of eczema is at least 10 percent, or more than 28 million
people in the United States. Immunocompromised persons are at high risk
for
progressive vaccinia. We know of no overall estimate for the number of
immunocompromised individuals in the United States. This number would
include recipients of organ transplants (184 000 solid-organ transplants
in
the 1990s), individuals with diagnosed and undiagnosed HIV infection or
AIDS (850 000), and patients with cancer (approximately 8.5 million).
We
estimate, therefore, that in the entire U.S. population as many as 10
million individuals (3.6 percent) may be at increased risk for developing
progressive vaccinia.
Therefore, approximately 15 percent of the population may have increased
risk for a direct adverse event after smallpox vaccination. In addition
to
exclusion of these individuals from vaccination, persons in close contact
with them should not be vaccinated to avoid inadvertent transmission and
subsequent indirect adverse events. Close contacts would include, at
minimum, household members. Insufficient data are available to estimate
precisely the number of close contacts who would be excluded from a
vaccination campaign. We estimate that another 10 percent of the population
would be excluded. On the basis of the foregoing, we further estimate that
25 percent of the population would be excluded from vaccination because
of
high risk or the possibility of coming in contact with a high-risk
individual." (<http://www.acponline.org/journals/ecp/marapr02/kemper.htm>)
(This article presents an excellent analysis of the potential risks and
necessary preventive actions should a mass vaccination campaign be
conducted, and I strongly urge interested readers to read the article in
its entirety.)
In an editorial accompanying the above article by Kemper et al, Dr. John
Modlin (chairperson of the ACIP committee hearing on Smallpox vaccination)
states: "Kemper and colleagues' back-of-the-envelope calculations remind
us
of the serious downsides of a universal vaccination strategy. Physicians
who have taken an oath to "first do no harm" will struggle with the idea
of
vaccinating their patients to ward off an ill-defined and seemingly remote
threat. Policymakers will need to weigh the best available analyses of
vaccine-related morbidity and costs against the best available assessment
of risk for a smallpox release. This will be an arduous and contentious
task but a necessary one."
(<http://www.acponline.org/journals/ecp/marapr02/modlin.htm>)
- Mod.MPP]
[see also:
Smallpox vaccine, ACIP recommendations - USA
20020620.4542
Smallpox vaccination
20020611.4468
Smallpox, diluted vaccine trial (13)
20020409.3919
Smallpox, diluted vaccine trial (05)
20020219.3587
Smallpox, diluted vaccine trial (12)
20020408.3904
2001
----
Smallpox, diluted vaccine trial
20011117.2827
Smallpox, diluted vaccine trial (02)
20011119.2844
Smallpox, diluted vaccine trial (03)
20011121.2850
Smallpox, diluted vaccine trial (04)
20011123.2870
Smallpox, re-vaccination & immunity
20011029.2672
Smallpox, re-vaccination & immunity (04)
20011107.2765
Smallpox vaccine, ACIP recommendations
20010623.1190
Smallpox vaccine, supply - USA
20011130.2915
Smallpox vaccine, WHO statement
20011025.2641
Smallpox vaccine, WHO statement (02)
20011027.2649
Smallpox vaccine recommendations - USA: update 20010226.0378]
.............................................mpp/pg/mpp
