Smallpox: Causes, Symptoms, Treatment & Types

What is Smallpox?

Smallpox is a serious infection caused by the variola virus and can spread quickly. For centuries, it has infected millions across the world, frequently resulting in scarring or death. Transmission occurs through person-to-person contact, mainly affecting the skin and producing a rash that progresses to blisters and scabs.

Smallpox was historically regarded as one of the most lethal infectious diseases. Global immunisation campaigns ultimately eliminated naturally occurring smallpox. The last naturally reported case occurred in 1977, and the World Health Organisation declared the disease eradicated in 1980.

What are the Types of Smallpox?

How Common is Smallpox in India?

Smallpox no longer occurs naturally in India or anywhere else in the world. Before smallpox was eradicated, India was among the countries most affected by the disease, reporting a large number of cases. During the 1970s, the infection continued to affect many parts of the country, making India one of the last places where smallpox remained active. However, large-scale vaccination efforts and close monitoring of the disease eventually helped eliminate it.

What are the Symptoms of Smallpox?

Symptoms of smallpox usually appear 7 to 19 days after infection, a period known as the incubation stage. During this time, a person may show no signs of illness.

The illness typically starts with early symptoms such as:

• High fever

• Severe headache

• Muscle pain and body aches

• Extreme tiredness

• Back pain

• Vomiting

• Chills and weakness

After a few days, a rash begins to appear, often starting inside the mouth or on the tongue before spreading to the skin. The rash commonly first appears on the face, arms, and legs before spreading to the trunk, hands, and feet.

Within one or two days, the rash develops into fluid-filled blisters. As the disease progresses, the blisters fill with pus and become firm, raised sores called pustules. Eventually, the sores dry, form scabs, and fall off, often leaving deep scars.

What Causes Smallpox?

Smallpox is caused by the variola virus, which mainly spreads through close contact with an infected person. The virus may spread in the following ways:

• Person-to-Person Contact: A person with smallpox may spread the virus by coughing, sneezing, or talking, which releases infected droplets into the air. Close contact with an infected person increases the risk of transmission.

• Direct Contact With Sores or Body Fluids: Touching the skin sores, blisters, or body fluids of a person with smallpox may also spread the infection.

• Contaminated Items: In some cases, clothes, blankets, bedsheets, or other personal items used by an infected person may carry the virus and spread infection. However, this is less common than direct contact.

• Airborne Spread: Although rare, the virus can sometimes spread through indoor air circulation, affecting people in nearby rooms or floors.

• Biological Weapon: Since smallpox no longer occurs naturally, the chances of infection are extremely low. However, health authorities remain prepared due to concerns about the possible misuse of the virus in the future.

What are the Stages of Smallpox?

What are the Complications of Smallpox?

Smallpox may cause severe health complications, especially in people with severe infection.

One of the most common long-term complications is permanent scarring, particularly on the face, arms, and legs. Many survivors carried visible marks throughout life.

In severe cases, smallpox may also lead to:

• Blindness

• Pneumonia

• Bone infections

• Joint deformities

• Brain inflammation (encephalitis)

• Low blood pressure

• Multi-organ failure

• Death

When Should I See My Healthcare Provider?

As smallpox no longer exists naturally, there is currently no risk of its contraction. However, immediate medical attention is necessary if a person develops symptoms resembling smallpox after a possible laboratory exposure or during a public health emergency.

Symptoms that need immediate medical attention include a sudden high fever that is followed by a rash that spreads across the body, especially if blisters filled with fluid or pus develop. In suspected cases, the person may be kept isolated to help prevent the infection from spreading.

How is Smallpox Diagnosed?

Healthcare professionals usually diagnose suspected smallpox by reviewing symptoms, examining the rash, and conducting laboratory tests to confirm the presence of the virus. Since smallpox symptoms can resemble those of other viral infections, proper testing is important for an accurate diagnosis.

The diagnosis process may include the following:

• Physical Examination: Healthcare professionals first look for common signs of smallpox, such as a high fever followed by a spreading rash. They also check whether the sores look similar across the body and how the rash changes over time.

• Blister Fluid Testing: A sample of blister or pustule fluid may be collected and tested for the presence of the variola virus.

• Scab Sample Testing: Since the virus can remain in scabs, healthcare professionals may collect a scab sample for further testing.

• Blood Tests: In some cases, blood samples may be taken to detect signs of infection or support diagnosis.

• PCR (Polymerase Chain Reaction) Test: This laboratory test helps detect viral genetic material and is one of the methods used to confirm infection.

What is the Difference Between Smallpox and Chickenpox?

Smallpox and chickenpox are different viral infections that can sometimes look similar because both cause fever and a rash. However, smallpox was a much more serious disease and could cause severe complications, while chickenpox is usually milder and more common today.

Although the two conditions may appear alike at first, there are several important differences in their symptoms, rash patterns, severity, and causes.

If a person develops fever and a rash, healthcare professionals may examine the appearance and pattern of the sores to help identify the condition and rule out other infections.

How is Smallpox Managed?

There is no universally proven treatment for naturally occurring smallpox. In the past, treatment mainly focused on supportive care to control symptoms and complications.

Supportive treatment is primarily focused on managing symptoms and supporting the body's recovery. This included keeping the person hydrated, controlling fever, caring for skin sores, and closely watching for any complications.

Today, antiviral medicines such as tecovirimat may help treat smallpox in emergencies. If a case is suspected, the infected person may also be kept in a specialised medical facility to help prevent the infection from spreading to others.

What is the Prognosis for Smallpox?

The prognosis of smallpox depended on the severity of infection. Mild forms had a better chance of recovery, while severe forms carried a higher risk of death. Historically, many survivors recovered but were left with permanent scars or vision problems. People who survived infection often developed prolonged immunity against the disease.

Can Smallpox be Reversed?

Smallpox itself cannot be reversed once infection develops. Historically, treatment focused on relieving symptoms and stopping complications rather than curing the infection. People who received the vaccine shortly after exposure were sometimes found to have less severe symptoms.

How Can I Prevent Smallpox?

Vaccination is considered one of the most effective ways of preventing smallpox.

Currently, routine vaccination is not recommended for the general public because naturally occurring smallpox no longer exists. Vaccines are mainly reserved for laboratory workers and emergency preparedness situations.If a smallpox outbreak ever happens, vaccination would be the primary means used by public health authorities to prevent its spread. Also, infected individuals would be isolated and closely monitored to combat the health risks.

Does Health Insurance Cover Smallpox?

Yes, health insurance in India may cover smallpox treatment if hospitalisation, diagnostic tests, medicines, or intensive medical care are required. Since smallpox is highly contagious, hospital treatment expenses may be covered under a standard health insurance plan, subject to the policy terms and conditions.

However, since smallpox does not occur anymore, coverage for such treatment is not usually a standard concern. Coverage may vary across insurance policies, including inclusions, waiting periods, exclusions, and hospitalisation benefits. It is advisable to check your policy documents closely to understand the exact scope of coverage.

How Much Health Insurance Coverage Is Needed for Smallpox Treatment?

The amount of health insurance coverage needed for smallpox treatment can depend on the severity of the condition and the type of medical care required. Since smallpox can lead to serious complications and may require hospitalisation, intensive monitoring, and specialised treatment, having sufficient health coverage may help manage unexpected medical expenses. In general, a health insurance cover of ₹5–10 lakhs may help cover hospitalisation and treatment costs for serious infectious diseases like smallpox.