DISEASE: SMALL POX

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. However, the disease is in the news again for the threat of its possible use as a bio-terror weapon by certain terrorist organizations.

The Disease

 Smallpox is a serious, contagious, and sometimes fatal infectious disease. There is no specific treatment for smallpox disease, and the only prevention is vaccination. The name smallpox is derived from the Latin word for spotted and refers to the raised bumps that appear on the face and body of an infected person. Smallpox is caused by the variola virus that emerged in human populations thousands of years ago.

Transmission

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. Rarely, smallpox has been spread by virus carried in the air in enclosed settings such as buildings, buses, and trains. Humans are the only natural hosts of variola. Smallpox is not known to be transmitted by insects or animals.

The Smallpox Vaccine

The smallpox vaccine helps the body develop immunity to smallpox. The vaccine is made from a virus called vaccinia which is a pox-type virus related to smallpox. The smallpox vaccine contains the live vaccinia virusnot dead virus like many other vaccines. For that reason, the vaccination site must be cared for carefully to prevent the virus from spreading. Also, the vaccine can have side effects. The vaccine does not contain the smallpox virus and cannot give you smallpox.

The smallpox vaccine is not given with a hypodermic needle. It is not a shot as most people have experienced. The vaccine is given using a bifurcated (two-pronged) needle that is dipped into the vaccine solution. When removed, the needle retains a droplet of the vaccine. The needle is used to prick the skin a number of times in a few seconds. The pricking is not deep, but it will cause a sore spot and one or two droplets of blood to form. The vaccine usually is given in the upper arm. If the vaccination is successful, a red and itchy bump develops at the vaccine site in three or four days. In the first week, the bump becomes a large blister, fills with pus, and begins to drain. During the second week, the blister begins to dry up and a scab forms. The scab falls off in the third week, leaving a small scar.

Smallpox Vaccine Safety and Side Effects

The smallpox vaccine is the best protection you can get if you are exposed to the smallpox virus. Anyone directly exposed to smallpox, regardless of health status, would be offered the smallpox vaccine because the risks associated with smallpox disease are far greater than those posed by the vaccine.

There are side effects and risks associated with the smallpox vaccine. Most people experience normal, usually mild reactions that include a sore arm, fever, and body aches. However, other people experience reactions ranging from serious to life-threatening. People most likely to have serious side effects are: people who have had, even once, skin conditions (especially eczema or 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 currently taking medications (like steroids) that suppress the immune system. In addition, 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, experts advise against non-emergency use of smallpox vaccine in children younger than 18 years of age. In addition, those allergic to the vaccine or any of its components should not receive the vaccine.

The Indian Scenario

What would happen if smallpox returned? An article in the latest issue of Population and Development Review assesses the prevalence and severity of smallpox in India during the nineteenth century. According to the authors, who analyzed demographic data from various historical sources, about 80 percent of Indias population was completely unprotected against smallpox in the eighteenth and early nineteenth century. Case fatality, or the proportion of people affected by the disease who die from it, was about 25 to 30 percent in unprotected populations.

The introduction into India of primary vaccination against smallpox in 1802 was eventually successful in largely controlling the disease. Although it took between seven and nine decades to establish the practice, mass primary vaccination resulted in a major decline in smallpox mortality by the end of the nineteenth century. The last recorded case of smallpox in India occurred in Assam in 1975. In 1980, the World Health Organization declared that smallpox was finally eradicated from the world. However, declaring the disease destroyed does not necessarily consign it to history.

There has been a recent debate as to whether or not the two remaining official stocks of the smallpox virusheld at the Russian State Research Center of Virology and Biotechnology in Koltsovo, Novosibirsk, and at the United States Centers for Disease Control and Prevention in Atlanta, Georgiashould be destroyed. Concern has been expressed that secret stocks of the virus may exist somewhere and could be released deliberately, either by a rogue nation state or by terrorists. It is also conceivable that live smallpox virus could emerge from a corpse that has been preserved in permafrost. Hence a recent editorial in The Lancet concludes that the threat of this disease still persists.

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