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Smallpox Fact Sheet for Patients

Smallpox is a serious, contagious, and sometimes fatal infectious disease. There is no specific treatment for smallpox disease, and the only prevention is vaccination. Smallpox outbreaks have occurred from time to time for thousands of years, but the disease is now eradicated after a successful worldwide vaccination program. The last case of smallpox in the United States was in 1949. The last naturally occurring case in the world was in Somalia in 1977. After the disease was eliminated from the world, routine vaccination against smallpox among the general public was stopped because it was no longer necessary for prevention.

Signs and Symptoms:

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.

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.

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.

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.

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.

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.

Should I get vaccinated against smallpox?
The smallpox vaccine is not available to the public at this time.

Smallpox FAQs for Healthcare Workers and Providers

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 response plan designed to quickly vaccinate people and contain a smallpox outbreak. This plan includes the creation of smallpox health care teams that would respond to a smallpox emergency and the vaccination of members of these teams. 2) There is enough smallpox vaccine to vaccinate everyone who would need it in the event of an emergency. 

Signs and Symptoms:

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.

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. 

How is smallpox spread?

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.

If people had smallpox previously and survived, are they immune from the disease?

Yes. If they had smallpox before and survived, they are immune to the disease. 

When are cases of smallpox infectious?

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.

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.

Why are we even bringing smallpox patients to the hospitals? Why not just keep them at home where they’ve already exposed everyone?

With good infection control practices and rooms with the appropriate air handling features, we can treat patients in the hospital without risking transmission to other patients and staff. The appropriate care and management of smallpox patients will probably require hospitalization.

What kind of personal protective equipment (PPE, especially respiratory) would be necessary for dealing with a smallpox patient?

Airborne and contact isolation precautions should be followed. 

Does a HEPA filter remove smallpox virus? Can a makeshift isolation room be created by bringing a portable HEPA filter into a regular private room?

Yes, HEPA filters do remove smallpox virus. HEPA filters are 99.97% efficient at removing particles that are greater than or equal to 0.3 microns in size, but their use will not create an airborne infection isolation room, (the precautions recommended for smallpox patients).

The HEPA filter will not change the pressure relationship to the corridor unless the portable filter is set up as a negative pressure device. Self-closing doors will help to maintain the conditions and windows should be closed and sealed. If the HEPA filter is being used only to purify the room air, its effectiveness will vary depending on the size of the room and output of the device. A portable HEPA filter that produces 8 or more air changes per hour results in a 90% reduction of particles in 17 minutes in a room with the doors and windows closed. However, to be consistent with current guidelines for airborne infection isolation rooms, the goal should be 12 or more air changes per hour which would produce a 90% reduction in particles in 11 minutes. 

Once a smallpox patient has been identified, what is the response for the hospital or clinic? Do we quarantine?

Until a case is confirmed, the recommendation would be the same as for any rash illness, such as measles. Get the suspect patient into a negative air pressure room and gather the name and locating information for those exposed to the patient. If they don't have a negative air pressure room, get them to a facility that does. State and local governments have primary responsibility for isolation and/or quarantine within their borders.

In caring for a patient with smallpox, does the vaccination status of a caregiver affect the N95 mask recommendation?

Anyone caring for a smallpox patient should wear an N95 mask.

If a health care provider has a contraindication or is at a high risk for infection, should they care for patients infected with smallpox? Ideally, these providers should not be in the vicinity of the patient or performing any patient care. 

What are the HIPAC recommendations for health care workers who may be exposed to patients with
smallpox or plague?

For smallpox, it is advisable that caregivers use a N95 mask respirator. For plague, a standard surgical mask is fine, and negative pressure rooms are not needed.

 

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