Smallpox: History, Symptoms, and the Vaccination Debate

Introduction and Historical Background

Recent concerns regarding bioterrorism have given rise to calls for a mass vaccination program against smallpox. The Bush administration floated plans to administer the smallpox vaccine to healthcare and military workers in order to protect against a potential smallpox outbreak in the United States. This paper examines the symptoms and morbidity rates of smallpox and studies the arguments both for and against a mass smallpox vaccination campaign.

Smallpox first appeared in northeastern Africa or the Indus Valley of south-central Asia nearly 12,000 years ago (Mayo Clinic 2002). Throughout history, outbreaks of smallpox occurred in various parts of the globe.

The smallpox contagion also played a decisive role in the colonization of the Americas. In the 15th century, European explorers acted as the unwitting carriers of smallpox to the New World. Because they lacked natural resistance, Native Americans quickly succumbed to the disease and transmitted the virus to other populations. In South America and the Caribbean, an estimated 8 to 20 million people died — many without ever encountering a European colonizer (de las Casas 2002).

The seeds of the smallpox vaccine were sown when scientists observed that people who survived smallpox were immune to the disease. To induce immunity, Chinese scientists used tubes to inhale powdered smallpox scabs, while Turkish scientists scratched pus from infected lesions into their skin. In 1788, English scientist Edward Jenner developed a variola vaccine from the less virulent cowpox virus. By the 1800s, cowpox vaccinations had become the widely accepted method of preventing smallpox (Mayo Clinic 2002).

The last occurrence of smallpox in the United States was documented in 1949 (CDC 2002), and smallpox vaccinations were discontinued in 1972. In 1980, in light of the global eradication of smallpox, the World Health Organization (WHO) recommended that all countries discontinue vaccinations.

Stocks of the virus, however, remain in high-security laboratories in the United States and Russia. In the 1980s, the Russians allegedly developed virulent smallpox strains for use as biological weapons. Health officials fear that the collapse of the former Soviet Union may have allowed some of this stock to fall into the wrong hands.

Pathology: What Happens to the Body

Smallpox causes pus-filled blisters, or pustules, on the skin. These eruptions leave severe, pitted scars. Experts estimate that up to one-third of victims who experience smallpox lesions will die from the disease.

Signs and Symptoms

The first symptoms of smallpox usually appear 12 to 14 days after initial infection. Patients experience a sudden onset of flu-like symptoms, including fever, bodily discomfort, headache, severe fatigue, and back pain (CDC Smallpox Factsheet 2002).

Once a host is infected, the virus immediately begins replicating. It targets the lymph nodes first, before invading the spleen and bone marrow. The virus then invades and multiplies in the host's blood vessels, with most of the variola mass concentrating in the vessels of the skin and mucous membranes.

At this stage, flat red spots called lesions appear on the host's face, hands, and forearms, later spreading throughout the body. The virus infects a victim's saliva through mouth lesions. Because the mucous membranes and saliva are the main sites of infection, a smallpox carrier typically transmits the virus through bodily fluids. The pattern of lesion distribution throughout the body is a hallmark of smallpox and a primary diagnostic indicator (CDC Smallpox Factsheet 2002).