How safe is the smallpox vaccine?

The smallpox vaccine is the best protection you can get if you are exposed
to the smallpox virus. Most people experience normal, usually mild reactions
that include a sore arm, fever, and body aches. In recent tests, one
in three people felt bad enough to miss work, school, or recreational
activity or had trouble sleeping after receiving the vaccine. However,
the vaccine does have some risks. In the past, about 1,000 people for
every 1 million people vaccinated for the first time experienced reactions
that, while not life-threatening, were serious.

These
reactions include a vigorous (toxic or allergic) reaction at the site
of the vaccination and spread of the vaccinia virus (the live virus
in the smallpox vaccine) to other parts of the body and to other people.
These reactions typically do not require medical attention. Rarely,
people have had very bad reactions to the vaccine. In the past, between
14 and 52 people per 1 million vaccinated experienced potentially life-threatening
reactions, including eczema vaccinatum, progressive vaccinia (or vaccinia
necrosum), or postvaccinal encephalitis. Based on past experience, it
is estimated that between 1 and 2 people out of every 1 million people
vaccinated will die as a result of life-threatening reactions to the
vaccine. Careful screening of potential vaccine recipients is essential
to ensure that those at increased risk do not receive the vaccine.

People
most likely to have side effects are people who have, or even once had,
skin conditions, (especially eczema or atopic dermatitis) and people with
weakened immune systems, such as those who have received a transplant,
are HIV positive, or are receiving treatment for cancer. Anyone who falls
within these categories, or lives with someone who falls into one of these
categories, should NOT get the smallpox vaccine unless they are exposed
to the disease.

Pregnant
women should not get the vaccine because of the risk it poses to the fetus.
Women who are breastfeeding should not get the vaccine. Children younger
than 12 months of age should not get the vaccine. Also, the Advisory Committee
on Immunization Practices (ACIP) advises against non-emergency use of
smallpox vaccine in children younger than 18 years of age.
(updated Dec 9, 2002)

Who
should NOT get the vaccine?

People who should not get the vaccine include anyone who is allergic to
the vaccine or any of its components; pregnant women; women who are breastfeeding;
anyone under 12 months of age; people who have, or have had, skin conditions
(especially eczema and atopic dermatitis); and people with weakened immune
systems, such as those who have received a transplant, are HIV positive,
are receiving treatment for cancer, or are taking medications (like steroids)
that suppress the immune system. (The Advisory Committee on Immunization
Practices [ACIP] advises against non-emergency use of smallpox vaccine
in anyone under 18 years of age.) These people should not receive the
vaccine unless they have been exposed to smallpox. (updated
Dec 9, 2002)

Should
you get the smallpox vaccine if you have a weakened immune system (e.g.,
you are immunocompromised)?

No, you should not be vaccinated, unless there is a smallpox outbreak
and you have been directly exposed to the smallpox virus. Vaccination
can cause deaths in people with weakened immune systems. Thus, there is
no need to take the risks associated with smallpox vaccination unless
you have been directly exposed to smallpox—and even then, you should first
consult a physician or health care provider. (added Nov 13, 2002)

Pregnant
women are discouraged from getting the vaccine. Is there a danger to them
(or to an unborn child) if broader vaccination occurs, increasing the
potential for contact with vaccinated people?

Pregnant women should NOT be vaccinated in the absence of a smallpox outbreak
because of risk of fetal infection. Inadvertent transmission of vaccinia
virus to a pregnant woman could also put the fetus at risk. Vaccinated
persons must be very cautious to prevent transmission of the vaccine virus
to pregnant women or other contacts. (added
Nov 13, 2002)

Is
there any way to treat bad reactions to the vaccine?

Two treatments may help people who have certain serious reactions to the
smallpox vaccine. These are Vaccinia Immune Globulin (VIG) and cidofovir.
By the end of December 2002 there will be more than 2,700 treatment doses
of VIG (enough for predicted reactions with more than 27 million people)
and 3,500 doses of cidofovir (enough for predicted reactions with 15 million
people). Additional doses of VIG are being produced, and measures are
underway to increase supplies of cidofovir as well. VIG and cidofovir
are both administered under investigational new drug (IND) protocol. (updated
Nov 26, 2002)

NEW!

Is
a
child under the age of 1 year in the household a contraindication to vaccination?

No,
the presence of a child under the age of 1 year in the household is not
a contraindication to vaccination. The Advisory Committee on Immunization
Practices (ACIP) met on January 14, 2003 to consider, among several issues,
the question of whether a child under the age of 1 year in the household
should be added to the conditions or situations that are considered a
contraindication to smallpox vaccination. A vote was taken and it was
confirmed that the presence of an infant in the household is not a contraindication
to vaccination.

Approved
language from this meeting on this subject was: "The ACIP does
not recommend vaccination of children and adolescents less than 18 years
in the current pre-vaccination program, and smallpox vaccine is contraindicated
for infants less than 1 year of age. The presence of an adolescent or
child (including an infant) in the household, however, is not a contraindication
to vaccination of other members of the household. Data suggests that the
risk of serious complications from transmission from an adult to a child
is extremely small. However, the ACIP recognizes that some programs may
defer vaccination of household contacts of infants less than 1 year of
age because of data suggesting a higher risk of adverse events among primary
vaccinees in this age group, compared with that among older children."

Vaccinated parents of young children need to be careful not to inadvertently
spread the virus to their children.

They
should follow site care instructions that are essential to minimizing
the risk of contact transmission of vaccinia. These precautions include
covering the vaccination site, wearing a sleeved shirt, and careful hand
washing anytime after touching the vaccination site or anything that might
be contaminated with virus from the vaccination site. If these precautions
are followed, the risk for children is very low. Individuals who do not
believe that they can adhere to such instructions should err on the side
of caution and not be vaccinated at this time. (added
Jan 29, 2003)

NEW!

Are
there any eye conditions that would preclude vaccination?

The
concern surrounding eyes is that frequent touching of the eyes by someone
who has gotten the smallpox vaccine may increase the chances that that
person will experience spread of the vaccinia virus to the eyes (inadvertent
inoculation of the eye) by touching the vaccine site or something contaminated
with live virus and then touching their eyes before they wash their hands.

This
side effect is a serious one because it can lead to damaged vision, or
even blindness. People who wear contact lenses, or touch their eyes frequently
throughout the day can get the smallpox vaccine, but they must be especially
careful to follow instructions for care of the smallpox vaccination site.
Frequent and thorough hand washing will minimize the chance of contact
spread of the vaccinia virus.

As
an additional precaution to minimize the risk of this type of transmission
in selected groups of people, on January 14, 2003, the Advisory Committee
on Immunization Practices (ACIP) decided that anyone with eye diseases
or other conditions (e.g. recent LASIK surgery) that require the use of
corticosteroid drops in the eye should wait until they no longer require
such treatment before getting vaccinated.

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