Smallpox
What
should I know about smallpox?
Smallpox is an acute, contagious, and sometimes fatal disease caused by the
variola virus (an orthopoxvirus), and marked by fever and a distinctive progressive
skin rash. In 1980, the disease was declared eradicated following worldwide
vaccination programs. However, in the aftermath of the events of September
and October, 2001, the U.S. government is taking precautions to be ready to
deal with a bioterrorist attack using smallpox as a weapon. As a result of
these efforts: 1) There is a detailed nationwide smallpox preparedness program
to protect Americans against smallpox as a biological weapon. This program
includes the creation of preparedness teams that are ready to respond to a
smallpox attack on the United States. Members of these teams - health care
and public health workers - are being vaccinated so that they might safely
protect others in the event of a smallpox outbreak. 2) There is enough smallpox
vaccine to vaccinate everyone who would need it in the event of an emergency.
(updated Feb 24, 2003)
How serious
is the smallpox threat?
The deliberate release of smallpox as an epidemic disease is now regarded as
a possibility, and the United States is taking precautions to deal with this
possibility. (added Nov 13, 2002)
How dangerous
is the smallpox threat?
Smallpox is classified as a Category A agent by the Centers for Disease Control
and Prevention. Category A agents are believed to pose the greatest potential
threat for adverse public health impact and have a moderate to high potential
for large-scale dissemination. The public is generally more aware of category
A agents, and broad-based public health preparedness efforts are necessary.
Other Category A agents are anthrax, plague, botulism, tularemia, and viral
hemorrhagic fevers. (added Nov 13, 2002)
If I
am concerned about a smallpox attack, can I go to my doctor and get the
smallpox vaccine?
At the moment, the smallpox vaccine is not available for members of the general
public. In the event of a smallpox outbreak, however, there is enough smallpox
vaccine to vaccinate everyone who would need it. (added Nov 13, 2002)
What
are the symptoms of smallpox?
The symptoms of smallpox begin with high fever, head and body aches, and sometimes
vomiting. A rash follows that spreads and progresses to raised bumps and pus-filled
blisters that crust, scab, and fall off after about three weeks, leaving a
pitted scar. (added Nov 13, 2002)
If someone
comes in contact with smallpox, how long does it take to show symptoms?
After exposure, it takes between 7 and 17 days for symptoms of smallpox to
appear (average incubation time is 12 to 14 days). During this time, the infected
person feels fine and is not contagious. (added Nov 13, 2002)
Is smallpox
fatal?
The majority of patients with smallpox recover, but death may occur in up to
30% of cases. Many smallpox survivors have permanent scars over large areas
of their body, especially their face. Some are left blind. (added Nov 13, 2002)
How is
smallpox spread?
Smallpox normally spreads from contact with infected persons. Generally, direct
and fairly prolonged face-to-face contact is required to spread smallpox from
one person to another. Smallpox also can be spread through direct contact with
infected bodily fluids or contaminated objects such as bedding or clothing.
Indirect spread is less common. Rarely, smallpox has been spread by virus carried
in the air in enclosed settings such as buildings, buses, and trains. Smallpox
is not known to be transmitted by insects or animals. (added Nov 13, 2002)
If smallpox
is released in aerosol form, how long does the virus survive?
The smallpox virus is fragile. In laboratory experiments, 90% of aerosolized
smallpox virus dies within 24 hours; in the presence of ultraviolet (UV) light,
this percentage would be even greater. If an aerosol release of smallpox occurs,
90% of virus matter will be inactivated or dissipated in about 24 hours. (added
Nov 13, 2002)
How many
people would have to get smallpox before it is considered an outbreak? One
confirmed case of smallpox is considered a public health emergency. (added
Nov 13, 2002)
Is smallpox
contagious before the smallpox symptoms show?
A person with smallpox is sometimes contagious with onset of fever (prodrome
phase), but the person becomes most contagious with the onset of rash. The
infected person is contagious until the last smallpox scab falls off. (added
Nov 13, 2002)
Is there
any treatment for smallpox?
Smallpox can be prevented through use of the smallpox vaccine. There is no
proven treatment for smallpox, but research to evaluate new antiviral agents
is ongoing. Early results from laboratory studies suggest that the drug cidofovir
may fight against the smallpox virus; currently, studies with animals are being
done to better understand the drug's ability to treat smallpox disease (the
use of cidofovir to treat smallpox or smallpox reactions should be evaluated
and monitored by experts at NIH and CDC). 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.
(updated Dec 2, 2002)
Page last modified March
31, 2003
