Smallpox Q and A (cont.)
Contaminated clothing or bed linen could also spread the virus. Special
precautions need to be taken to ensure that all bedding and clothing of patients
are cleaned appropriately with bleach and hot water. Disinfectants such as
bleach and quaternary ammonia can be used for cleaning contaminated surfaces.
If someone is exposed to smallpox, is it too late to get a vaccination?
If the vaccine is given within 4 days after exposure to smallpox, it can
lessen the severity of illness or even prevent it.
If people got the vaccination in the past when it was used routinely, will
they be immune?
Not necessarily. Routine vaccination against smallpox ended in 1972. The
level of immunity, if any, among persons who were vaccinated before 1972 is
uncertain; therefore, these persons are assumed to be susceptible. For those who
were vaccinated, it is not known how long immunity lasts. Most estimates suggest
immunity from the vaccination lasts 3 to 5 years. This means that nearly the
entire U.S. population has partial immunity at best. Immunity can be boosted
effectively with a single revaccination. Prior infection with the disease grants
How many people have not had the vaccination?
Approximately half of the U.S. population has never been vaccinated.
Is it possible for people to get smallpox from the vaccination?
No, smallpox vaccine does not contain smallpox virus but another live virus
called vaccinia virus. Since this virus is related to smallpox virus,
vaccination with vaccina provides immunity against infection from smallpox
How safe is the smallpox vaccine?
Smallpox vaccine is considered very safe. Some people are at greater risk for serious side effects from the smallpox
vaccine. Adverse reactions have been
known to occur that range from mild rashes to rare fatal encephalitis and
Individuals who have any of the following conditions, or live with
someone who does, should NOT get the smallpox vaccine unless they have been
exposed to the smallpox virus:
- Eczema or atopic dermatitis. (This is true even if the condition is not
currently active, mild or experienced as a child.)
- Skin conditions such as burns, chickenpox, shingles, impetigo, herpes,
severe acne, or psoriasis. (People with any of these conditions should not
get the vaccine until they have completely healed.)
- Weakened immune system. (Cancer treatment, an organ transplant, HIV, or
medications to treat autoimmune disorders and other illnesses can weaken the
- Pregnancy or plans to become pregnant within one month of vaccination.
In addition, individuals should not get the smallpox vaccine if they:
Again, people who have been directly exposed to the smallpox virus should
get the vaccine, regardless of their health status.
- Are allergic to the vaccine or any of its ingredients.
- Are younger than 12 months of age. However, the Advisory Committee on
Immunization Practices (ACIP) advises against non-emergency use of smallpox
vaccine in children younger than 18 years of age.
- Have a moderate or severe short-term illness. (These people should wait
until they are completely recovered to get the vaccine.)
- Are currently breastfeeding.
If offered the smallpox vaccine, individuals should
tell their immunization provider if they have any of the above conditions, or
even if they suspect they might.
Is there any treatment for smallpox?
There is no proven treatment for smallpox, but research to evaluate new
antiviral agents is ongoing. Patients with smallpox can benefit from supportive
therapy (e.g., intravenous fluids, medicine to control fever or pain) and
antibiotics for any secondary bacterial infections that may occur.
Is there a test to indicate if smallpox is in the environment like there is
Various agencies are currently validating tests designed to test for the
smallpox virus in the environment.
If smallpox is discovered or released in a building, or if a person develops
symptoms in a building, how can that area be decontaminated?
The smallpox virus is fragile and in the event of an aerosol release of
smallpox, all viruses will be inactivated or dissipated within 1-2 days.
Buildings exposed to the initial aerosol release of the virus do not need to be
decontaminated. By the time the first cases are identified, typically 2 weeks
after the release, the virus in the building will be gone. Infected patients,
however, will be capable of spreading the virus and possibly contaminating
surfaces while they are sick. Therefore, standard hospital grade disinfectants
such as quaternary ammonias are effective in killing the virus on surfaces
should be used for disinfecting hospitalized patients' rooms or other
contaminated surfaces. Although less desirable because it can damage equipment
and furniture, hypochlorite (bleach) is an acceptable alternative. In the
hospital setting, patients' linens should be autoclaved or washed in hot water
with bleach added. Infectious waste should be placed in biohazard bags and
autoclaved before incineration.
What should people do if they suspect a patient has smallpox or suspect that
smallpox has been released in their area?
Report suspected cases of smallpox or suspected intentional release of
smallpox to your local health department. The local health department is
responsible for notifying the state health department, the FBI, and local law
enforcement. The state health department will notify the CDC.