Smallpox in News: Key Facts, Vaccine & Eradication (UPSC)

The recent demise of William Foege, the global health leader who played a pivotal role in eradicating smallpox worldwide, has brought renewed focus on Smallpox disease.

• Linked to Science & Technology – Biology (Viruses)
• Part of GS Paper I & GS Paper III (Health, Public Health)
• Important for Prelims disease–virus–vaccine matching
• Useful for Mains answers on public health & global cooperation

Smallpox is an acute contagious disease caused by the variola virus, a member of the orthopoxvirus family. It was one of the most devastating diseases known to humanity and caused millions of deaths before it was eradicated. It is believed to have existed for at least 3000 years. The disease caused high fever followed by a distinctive skin rash, which often left permanent scars on survivors and led to death in many cases.

• Causative Agent: Variola virus
• Type of Virus: Double-stranded DNA virus
• Virus Family: Orthopoxvirus
• Natural Host / Reservoir: Humans only

Smallpox existed in two forms:

• Variola major: Severe form with high death rate
• Variola minor: Milder form with low fatality

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Smallpox is one of the oldest known infectious diseases affecting humans. Evidence of the disease has been found across ancient civilisations, showing its long and devastating impact on human history.

Ancient Origins (Before Common Era)

• Evidence of smallpox-like lesions has been found on Egyptian mummies, including Pharaoh Ramses V (around 1157 BCE).
• Ancient texts from India and China describe symptoms similar to smallpox.
• The disease spread through trade routes, wars, and migration.

Spread Across Continents (Middle Ages)

• Smallpox became widespread in Europe, Asia, and Africa by the Middle Ages.
• It caused frequent epidemics, killing millions and affecting all social classes.
• Mortality was particularly high among children.

Smallpox and Colonisation (15th–18th Century)

• Smallpox was carried to the Americas by European explorers in the 16th century.
• Indigenous populations had no immunity, leading to massive deaths.
• The disease played a role in the collapse of native civilisations in the Americas.

Discovery of Vaccination (1796)

• In 1796, Edward Jenner developed the first successful vaccine.
• He used the cowpox virus to protect against smallpox.
• He observed that milkmaids who previously had caught cowpox did not catch smallpox and showed that a similar inoculation could be used to prevent smallpox in other people.
• The term “vaccination” comes from vacca (Latin for cow).

Global Control Efforts (20th Century)

• By the early 1900s, smallpox was controlled in many developed countries.
• However, it remained endemic in parts of Asia and Africa.

WHO Eradication Programme (1959–1980)

• 1959: WHO launched the Global Smallpox Eradication Programme
• 1967: Programme intensified with better funding and surveillance
• 1977: Last natural case recorded in Somalia

1980: WHO declared smallpox eradicated – the only infectious disease to achieve this distinction. 

This remains among the most notable and profound public health successes in history.

Smallpox was caused by the Variola virus, which spread exclusively through human-to-human transmission. Since humans were the only natural host, the disease did not involve animals or insects (i.e., it was not zoonotic) in its transmission cycle.

Modes of Transmission

Smallpox spread mainly through close and prolonged contact with an infected person.

1. Respiratory Droplet Transmission

• Virus spread through droplets released during coughing, sneezing, or talking
• Required face-to-face contact, especially in closed spaces
• Common in households and hospitals

2. Direct Contact Transmission

• Occurred through touching skin lesions, pustules, or scabs
• Highly infectious during the rash stage

3. Indirect (Fomite) Transmission

Virus could spread via contaminated objects such as:

• Clothes
• Bed sheets
• Towels
• Dried scabs remained infectious for long periods

Smallpox was not airborne over long distances and did not spread through water or food.

Incubation Period and Infectious Stage

• Incubation period was 7–17 days
• Infected individuals did not transmit the virus during incubation
• Maximum infectivity was during the rash and pustular stages

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Smallpox had a high fatality rate (≈30%), making it one of the deadliest diseases in history. Key symptoms include:

• High fever, severe headache, body pain
• Characteristic centrifugal rash (starts on face → limbs)
• Lesions appear synchronously: Macules → Papules → Vesicles → Pustules → Scabs
• Survivors often had permanent scars (pockmarks)

The development of an effective vaccine was the most important factor behind the global eradication of smallpox.

• Vaccine used: Vaccinia virus (related virus, not variola). It belongs to the Poxviridae family
• Type: Live attenuated vaccine

Storage of Smallpox Virus Samples

Live Variola virus samples are stored only under WHO supervision in two high-security laboratories:

• United States – Centres for Disease Control and Prevention (CDC), Atlanta
• Russia – VECTOR Research Centre

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For UPSC Prelims, understanding how smallpox differs from similar diseases is important.

Smallpox & Bioterrorism 

Smallpox is classified as a Category A bioterror agent. Here's why:

• High infectivity
• Lack of population immunity
• High fatality rate

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Smallpox remains a landmark topic in public health as the only human disease eradicated globally. Understanding its cause, transmission, vaccine, and the role of William Foege’s ring vaccination strategy is essential for tackling Prelims comparison-based questions and enriching Mains answers on health governance and global cooperation.