- What is smallpox?
- How is smallpox spread?
- What are the symptoms of smallpox?
- How soon after exposure do symptoms appear?
- How long can an infected person spread the virus?
- What is the treatment for smallpox?
- How does my doctor tell the difference between smallpox and chickenpox?
- Is there a vaccine for smallpox?
- Can I get vaccinated?
- What if I have already had the vaccine?
- If smallpox were used as a biological weapon, how would we control its spread?
- Are we expecting smallpox to be used as a biological weapon?
Smallpox is a serious infectious disease caused by the Orthopox virus, variola. The last case in Vermont occurred in 1937, and there have been no confirmed cases worldwide since eradication was achieved in 1978. A single case today would be considered a national public health emergency.
Smallpox spreads from person to person mainly by aerosolized droplets that come from the coughing of infected patients. Contact with smallpox scabs or contaminated clothing or linens can also spread the disease. Animals or insects are not known to act as reservoirs or transmit the disease.
The first symptoms may include high fever, vomiting, fatigue and backache. A raised spotted rash appears in two to three days, first in the mouth and throat, followed by a rash on the face and arms, which then spreads to the legs. The rash starts with flat red lesions; after one or two days the rash bumps become filled with fluid and later pus. Scabs form over the blisters, which will later fall off, about three to four weeks after the person becomes infected.
Symptoms usually appear in about 12 days, but can range from seven to 17 days.
Infected persons can spread the disease until all the scabs have fallen off the skin. This usually happens about three to four weeks after the rash began. Virus is also present in the scabs themselves.
At this time, there is no proven treatment for smallpox. Patients with smallpox can benefit from supportive therapy, including treatment to keep the patient as comfortable as possible by keeping the skin clean, trying to control the itching, relieving the pain and other symptoms as much as possible. Antibiotics would be used only if a secondary bacterial infection developed as a complication.
There is a vaccine to prevent smallpox. The United States stopped routine use of the vaccine in 1972 when it appeared that smallpox was under control worldwide. Drug companies stopped making the vaccine at about that time. The stored vaccine supply in the United States is under the control of the Centers for Disease Control and Prevention (CDC).
No. Routine vaccination for smallpox ended in 1972. Because of the limited availability of vaccine and the possibility of severe side effects in some people, routine vaccination against smallpox is not recommended to prevent the disease in the general public. However, if a person gets exposed to smallpox, there is vaccine available, and if it's given within four days after exposure, it can lessen the severity of, or even prevent, the disease.
Since smallpox vaccine requires a booster dose every ten years to remain effective, people who were vaccinated as children are most likely not protected now. People that already had the disease cannot get it again.
If smallpox were diagnosed today, the same strategies that were used to control and eradicate this disease in the past would be used again. People ill with smallpox would be isolated. CDC would immediately airlift its reserved smallpox vaccine to the affected area. If the vaccine is given within four days after exposure to smallpox, it can lessen the severity of or even prevent the disease. Therefore, isolation and vaccination can effectively stop the spread of smallpox. All individuals suspected to have been exposed to smallpox would be quarantined and vaccinated. Health care and emergency response workers responsible for treating exposed persons would also be vaccinated.
The United States is not expecting a smallpox attack from terrorists. While there are concerns that smallpox virus could be held by terrorists, there are considerable technical and logistical barriers to the production and dissemination of smallpox virus as a weapon. Consequently, many experts believe the actual probability of using smallpox as a weapon for bioterrorism is quite low. Public Health authorities and medical care providers are working together to learn more about smallpox so that any cases that might appear will be detected early and prevention measures to halt the spread will be put in place.
For more information about smallpox, call the Vermont Department of Health, Epidemiology Field Unit, 1-800-640-4374 (VT only) or 802-863-7240.