Smallpox

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Basics

• Summary
• Start Here
• Symptoms
• Prevention and Risk Factors

Learn More

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Research

• Clinical Trials
• Journal Articles

Resources

• Find an Expert

For You

• Teenagers
• Patient Handouts

Summary

Smallpox is a disease caused by the Variola major virus. Some experts say that over the centuries it has killed more people than all other infectious diseases combined. Worldwide vaccination stopped the spread of smallpox three decades ago. The last case was reported in 1977. Two research labs still keep small amounts of the virus. Experts fear bioterrorists could use the virus to spread disease.

Smallpox spreads very easily from person to person. Symptoms are flu-like. They include:

• High fever
• Fatigue
• Headache
• Backache
• A rash with flat red sores

There is no treatment. Fluids and medicines for pain or fever can help control symptoms. Most people recover, but some can die. Those who do recover may have severe scars.

The U.S. stopped routine smallpox vaccinations in 1972. Military and other high-risk groups continue to get the vaccine. The U.S. has increased its supply of the vaccine in recent years. The vaccine makes some people sick, so doctors save it for those at highest risk of disease.

Start Here

• Questions and Answers on Smallpox (World Health Organization)
• Smallpox (Mayo Foundation for Medical Education and Research) Also in Spanish
• Smallpox (National Institute of Allergy and Infectious Diseases)
• What Is Smallpox? (Centers for Disease Control and Prevention)

Symptoms

• Smallpox Signs and Symptoms (Centers for Disease Control and Prevention)

Prevention and Risk Factors

• Smallpox Vaccine (Centers for Disease Control and Prevention)
• Smallpox/Monkeypox Vaccine (JYNNEOS): What You Need to Know (Centers for Disease Control and Prevention) - PDF Also in Spanish

Clinical Trials

• ClinicalTrials.gov: Smallpox (National Institutes of Health)

Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)

• Article: Approaches to Next-Generation Capripoxvirus and Monkeypox Virus Vaccines.
• Article: Historical analysis of the first smallpox vaccination campaigns in early 19-century...
• Article: Short-Lived Neutralizing Antibody Responses to Monkeypox Virus in Smallpox Vaccine-Naive Persons...
• Smallpox -- see more articles

Find an Expert

• Centers for Disease Control and Prevention Also in Spanish
• National Institute of Allergy and Infectious Diseases
• World Health Organization

Teenagers

• Smallpox (Nemours Foundation) Also in Spanish

Patient Handouts

• Smallpox (Medical Encyclopedia) Also in Spanish
• Smallpox/Monkeypox Vaccine (JYNNEOS): What You Need to Know (Centers for Disease Control and Prevention) - PDF Also in Spanish