As mpox cases spread across Europe, experts suggest this rise may be linked to declining immunity against its far more lethal relative, smallpox.
In 1970, doctors in the Democratic Republic of Congo encountered a case that would reignite fears thought to have been eradicated. A nine-year-old boy in a remote village developed a severe rash. The skin lesions covering his body bore a striking resemblance to smallpox, an ancient disease that had devastated empires, wiped out civilizations, and claimed approximately 300 million lives in the 20th century alone.
Smallpox was believed to be eradicated in the DRC, but scientists feared that this case, found in an unvaccinated child, might have been overlooked. Tests later confirmed that the child was suffering from monkeypox (now called mpox), a close relative of smallpox, belonging to the orthopoxvirus family (which also includes cowpox and raccoonpox). Although mpox was first identified in 1958 during outbreaks in research monkeys, this was the first recorded human case.
Today, mpox is spreading across Europe and experts believe this rise is tied to declining immunity against smallpox. Here’s a deeper look into the historical context of smallpox and its connection to mpox:
- The first documented death: While smallpox was clinically described in Chinese medical texts as early as 1122 BC, the earliest evidence of a fatality comes from Egypt. The mummified remains of Pharaoh Ramesses V, who died in 1157 BC, show signs of smallpox.
- Smallpox and the fall of Rome: The virus reached the Roman Empire around 165 AD, sparking the Antonine Plague, a pandemic that killed around seven million people and marked the first major outbreak of smallpox.
- The devastation of the Aztecs: When Christopher Columbus arrived in the Americas in 1492, he wasn’t alone. Smallpox, brought by European settlers, unleashed an unintentional genocide. The indigenous population, estimated at around 54 million before 1492, was decimated by the virus, slavery, and massacres. The Aztec population in Mexico fell from 17.2 million to just one million by the end of the 16th century. The epidemic, known locally as “cocoliztli,” ravaged the region, facilitating Hernan Cortés’s conquest of the Aztec capital, Tenochtitlan, with a mere 600 troops.
- Biological warfare in the Americas: Smallpox was weaponized during the 18th-century conflicts between England and France in North America. In 1757, following the surrender of Fort William-Henry, Indian allies of the French contaminated themselves by handling corpses of Englishmen who had died of smallpox. Later, in 1763, during the siege of Fort Pitt, English forces sent smallpox-infected blankets to the Delaware Indians, decimating their ranks and turning the tide of the conflict.
- Beer as a treatment: Before the advent of vaccines, smallpox was treated using various traditional methods. Dr. Thomas Sydenham, who lived between 1624 and 1689, recommended unconventional treatments, such as keeping windows open, ensuring bedclothes were only waist-high, and administering “twelve bottles of small beer every twenty-four hours” to his patients.
- Early vaccination practices: Long before modern vaccines, ancient civilizations practiced variolation, inserting pus or crusts from smallpox lesions into the skin or noses of healthy individuals. This method, originating in China, India, Egypt, and Ethiopia, carried risks but significantly reduced mortality rates compared to natural infection, with only 0.5-2% of people dying from the procedure.
- Edward Jenner’s experiment: Dr. Edward Jenner, known as the father of vaccination, noticed that milkmaids who contracted cowpox, a milder disease, seemed immune to smallpox. To test his hypothesis, he inoculated his son and two maids with cowpox. When later exposed to smallpox, they remained healthy, confirming the protective effect of cowpox and leading to the development of the smallpox vaccine. By 1807, 165,000 people in England had been vaccinated.
- The birth of the anti-vax movement: The smallpox vaccine faced significant resistance, leading to the first organized anti-vaccination movements. In the late 19th century, tens of thousands of people protested against the smallpox vaccine, with some arguing that using material from cows was unchristian and unhealthy. Others opposed the compulsory nature of vaccination. Riots and organized opposition, such as anti-vaccination leagues, emerged.
- The only human disease eradicated: In 1959, the World Health Organization launched a global campaign to eradicate smallpox. Despite initial setbacks due to funding and logistical challenges, the campaign succeeded by 1977, following intensified efforts and widespread vaccination. The eradication of smallpox was hailed as “nothing short of a public health miracle” by the WHO.
- The last smallpox death: In the 20th century, smallpox killed approximately 300 million people. The last known victim was Janet Parker, a medical photographer in England, who died in 1978 after being exposed to the virus at a research lab. Her death led to the suicide of Professor Henry Bedson, the head of the smallpox laboratory.
- The lingering threat and the rise of mpox: Today, only two high-security labs, in Moscow and Atlanta, retain samples of the smallpox virus for research purposes. Concerns remain that these samples could be accidentally released or used as biological weapons. Meanwhile, declining immunity to smallpox may be contributing to the rise in mpox cases. With fewer than one in three people now protected against smallpox, the virus spreads more easily. Recent outbreaks have prompted ring vaccination campaigns using the smallpox vaccine, which is 85% effective against mpox. However, there are concerns that the virus could become entrenched if it spreads from humans to pets and wildlife.
The trajectory of mpox remains uncertain. While experts believe the current outbreak is still containable, its spread highlights the enduring relevance of smallpox, even decades after its eradication. (Source: Telegraph)
Essentials in vaccinology you should know considering smallpox/mpox:
- Smallpox was a severe disease-causing substantial mortality among populations over several thousand years.
- It is caused by an orthopoxvirus, the variola (= smallpox) virus.
- Smallpox is a febrile disease with a maculo-, papulo-, vesicular and finally pustular rash, the typical pox lesions, numerous complications and a fatality rate of approximately 30%.
- Material from smallpox patients was used to inoculate healthy subjects (“variolation”) in medieval China, possibly offering some protection, but it was associated with high risk of complications and death.
- In 1796, the English physician Edward Jenner discovered that material from cowpox lesions inoculated into healthy subjects protected against smallpox in a comparatively safe way. This discovery was the invention of vaccination.
- Vaccination campaigns in the 19th and 20th century-controlled smallpox, and following a global WHO-coordinated eradication campaign, it was finally declared eradicated by 1980.
- Other orthopoxviruses, such as the mpox virus, are still causing human disease in some geographies and may be emerging due to waning population immunity and population growth in previously rural or forested areas.
- Two antiviral compounds have been licensed for specific treatment.
- Various vaccines based on Jenner’s invention, using scarification with replicating live vaccinia strains, are still available globally for outbreaks.
- In the Western world, two smallpox vaccines are licensed and stockpiled today for emergency use:
– ACAM2000, a cell culture GMP-produced vaccinia strain; and
– a non-replicating, “Modified Vaccinia Ankara” (MVA) vaccine, GMP-produced on chicken embryo fibroblasts. (Source: VacciTUTOR)
By Daniela A. La Marca, Global Health Press
