Smallpox
Causes, Symptoms, Treatment & Prevention
Smallpox is a serious and contagious disease caused by the variola virus. Once one of the deadliest diseases worldwide, smallpox was declared eradicated in 1980 following a global vaccination campaign. No natural cases occur today; virus stocks are retained in secure laboratories for research and public health preparedness.
Transmission
Smallpox spreads through direct contact with infected individuals or contaminated objects and via respiratory droplets during prolonged face-to-face interaction.
Symptoms
- •High fever
- •Fatigue
- •Severe headache
- •Back pain
- •Vomiting
- •Rash that starts on the face and spreads to the limbs
- •Raised bumps that become pus-filled blisters, then scab over and fall off
Diagnosis
Because smallpox no longer occurs naturally, any suspected case would be treated as a public health emergency. Diagnosis would be confirmed through laboratory testing, including virus isolation and molecular testing (PCR).
Treatment
There is no definitive cure for smallpox. Supportive care can help manage symptoms. Antiviral medications such as tecovirimat (TPOXX) and brincidofovir have been approved for use in the event of an outbreak.
Prevention
Vaccination is the most effective prevention. Routine vaccination ended after eradication, but smallpox vaccine stocks remain for use in certain groups (e.g., laboratory workers, military) and would be deployed using strategies such as ring vaccination during an outbreak.
Sources
- Written by Love Hurts, Inc.
- Medically Reviewed by Kecia Gaither, MD. on November 1, 2025
- CDC: "Smallpox – CDC Fact Sheet"
- WHO: "Smallpox"
- Mayo Clinic: "Smallpox Overview"
- WebMD: "What Is Smallpox?"

