Smallpox

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.

National Institute of Allergy and Infectious Diseases

Find an Expert

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

Clinical Trials

• ClinicalTrials.gov: Smallpox National Institutes of Health

Journal Articles

• Smallpox

Start Here

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

Patient Handouts

• Smallpox Medical Encyclopedia
• Vaccine Information Statement (VIS) — Smallpox/Monkeypox Vaccine (JYNNEOS): What You Need to Know Centers for Disease Control and Prevention

Teenagers

• Smallpox Nemours Foundation

Images

• Smallpox (Variola) VisualDX

Symptoms

• Smallpox Signs and Symptoms Centers for Disease Control and Prevention

Prevention and Risk Factors

• Smallpox/Monkeypox Vaccine Information Statement Centers for Disease Control and Prevention
• Vaccine Basics: Smallpox Centers for Disease Control and Prevention