Measles vs. Smallpox

What's the Difference?

Measles and smallpox are both highly contagious viral diseases that have plagued humanity for centuries. However, there are significant differences between the two. Measles is caused by the measles virus, while smallpox is caused by the variola virus. Measles primarily affects the respiratory system, causing symptoms such as fever, cough, runny nose, and a characteristic rash. On the other hand, smallpox affects the entire body, resulting in high fever, severe rash, and often leading to complications such as blindness and death. Another crucial distinction is that smallpox has been eradicated globally, thanks to an effective vaccine, while measles remains a significant public health concern in many parts of the world.


Photo by CDC on Unsplash
Caused byVirusVirus
TransmissionAirborne dropletsAirborne droplets
SymptomsFever, rash, cough, runny noseFever, rash, headache, fatigue
Incubation period10-14 days7-17 days
ComplicationsPneumonia, encephalitis, deathSevere scarring, blindness, death
Vaccine availabilityAvailableNot available (eradicated)
PreventionVaccinationN/A (eradicated)
Photo by CDC on Unsplash

Further Detail


Measles and smallpox are two highly contagious viral diseases that have plagued humanity for centuries. While both diseases have caused significant morbidity and mortality throughout history, they differ in various aspects, including their transmission, symptoms, complications, and vaccination strategies. In this article, we will delve into the attributes of measles and smallpox, highlighting their similarities and differences to gain a better understanding of these formidable diseases.


Measles and smallpox differ in their modes of transmission. Measles is primarily transmitted through respiratory droplets when an infected person coughs or sneezes. The virus can remain infectious in the air or on surfaces for up to two hours, making it highly contagious. Smallpox, on the other hand, is transmitted through direct face-to-face contact with an infected individual or through respiratory droplets. Unlike measles, smallpox can also spread through contaminated objects such as bedding or clothing.

Furthermore, the incubation periods of these diseases differ. Measles has an incubation period of around 10-12 days, during which an infected person may not exhibit any symptoms but can still transmit the virus. In contrast, smallpox has a longer incubation period of 7-17 days, with the infected individual becoming contagious once the characteristic rash appears.


Both measles and smallpox present with distinct symptoms, although there are notable differences. Measles typically begins with a high fever, cough, runny nose, and red, watery eyes. These symptoms are followed by the appearance of small white spots on the inside of the cheeks, known as Koplik's spots. A few days later, a red, blotchy rash develops, starting on the face and gradually spreading to the rest of the body.

Smallpox, on the other hand, presents with a sudden onset of high fever, severe headache, and body aches. These symptoms are accompanied by a characteristic rash that progresses through different stages. Initially, flat, red spots appear on the face and extremities, which then develop into raised bumps filled with thick fluid. Eventually, these bumps form pustules that scab over and leave permanent scars.


Both measles and smallpox can lead to severe complications, although the risks associated with each disease differ. Measles can cause ear infections, pneumonia, and encephalitis (inflammation of the brain), particularly in young children. In rare cases, measles can result in long-term brain damage or even death. Additionally, measles infection can weaken the immune system, making individuals more susceptible to other infections for several weeks to months.

Smallpox, on the other hand, is known for its high mortality rate, with approximately 30% of infected individuals dying from the disease. Survivors often suffer from severe scarring and may experience long-term complications such as blindness, limb deformities, and infertility. Smallpox can also lead to secondary bacterial infections, which further increase the risk of mortality.


Vaccination has played a crucial role in the control and eradication of both measles and smallpox. The measles vaccine, typically administered as part of the measles-mumps-rubella (MMR) vaccine, is highly effective in preventing measles infection. It is recommended for all children and adults who have not previously been vaccinated or had measles. The MMR vaccine provides long-lasting immunity and has significantly reduced the incidence of measles worldwide.

Smallpox, on the other hand, is the only human disease to have been eradicated through vaccination. The smallpox vaccine, known as the vaccinia vaccine, was developed in the late 18th century and led to the successful eradication of smallpox in 1980. The vaccine provided immunity against the variola virus, the causative agent of smallpox. Due to the eradication of smallpox, routine smallpox vaccination is no longer necessary.


Measles and smallpox, although both viral diseases, differ in various aspects such as transmission, symptoms, complications, and vaccination strategies. Measles is highly contagious and primarily transmitted through respiratory droplets, while smallpox spreads through direct contact and contaminated objects. Measles presents with a characteristic rash and can lead to complications such as pneumonia and encephalitis. Smallpox, on the other hand, causes a severe rash that progresses through different stages and has a higher mortality rate. Vaccination has been instrumental in controlling and eradicating both diseases, with the MMR vaccine effectively preventing measles and the smallpox vaccine leading to the eradication of smallpox. Understanding the attributes of these diseases is crucial in implementing effective prevention and control measures to protect public health.

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