Diphtheria was once a leading childhood killer before antibiotics and vaccines

Penicillin ended scarlet fever’s deadly threat to children

Between 1840 and 1883, scarlet fever was among the leading causes of childhood death in the United States, with case fatality rates ranging from 15% to 30%. Today, thanks to antibiotics like penicillin, the mortality rate is below 1%.

Pneumonia was once a leading killer before penicillin treatments

In the early 20th century, pneumonia was a top cause of death worldwide, often fatal without effective treatment. Penicillin turned a once deadly infection into one of the most treatable bacterial diseases.

The measles vaccine has saved an estimated 94 million lives since its introduction.

A 1954 outbreak at a Boston boarding school allowed scientists to isolate the measles virus and formed the basis for the first measles vaccine.

Penicillin slashed battlefield pneumonia deaths during World War II

Before antibiotics, bacterial pneumonia killed about 18% of infected soldiers in World War I. By World War II, penicillin cut that death rate to less than 1%.

Measles infection, which was nearly universal during childhood in prevaccine era, was described by the Persian physician Rhazes in the 10th century as "more to be dreaded than smallpox."

Penicillin was hailed as a 'wonder drug' upon its release

When penicillin became widely available in the 1940s, newspapers and doctors alike celebrated it as a “wonder drug” that could cure infections once considered fatal.

Improved 19th-century sanitation meant kids encountered polio later, with worse results

Almost all children likely used to contract poliovirus, but scientists suggest that when infants encountered it very early in life—due to poorer conditions and hygiene—they still had some maternal protection from pregnancy or through breastmilk, so the symptoms were more flu-like.

Before vaccines, there was 'variolation': what was it?

Before the technology behind vaccinations was discovered, some keen observers of medicine around the globe noticed how previous infections could impact future ones. Learn about the techniques early physicians used before they had vaccines.

Penicillin has saved an estimated 500 million lives since its creation

Since its introduction in the 1940s, penicillin and related antibiotics are estimated to have saved around 500 million lives worldwide—making it one of the most consequential medical breakthroughs in human history.

Penicillin is considered one of history’s greatest medical breakthroughs

Experts widely rank penicillin’s discovery among the most important advances in medicine. It launched the antibiotic era, transformed once-deadly infections into treatable illnesses.

Two-thirds of antibiotic classes were made between the 1940s and 1960s

The vast majority of bacterial treatments were developed during the "Golden Age of Antibiotics," an era of rapid innovation and drug discovery that led to the reduction of millions of deaths worldwide. Since 1970, only eight new antibiotic classes have been discovered.

Variola: the second-deadliest virus on Earth

Because it was declared eradicated in 1980, many forget smallpox is one of history's deadliest diseases—in its final century, it's estimated to have claimed 500 million lives. This 11-minute video from production studio Kurzgesagt takes a look at...

In 2012, a virus that causes HFMD may have killed dozens of kids in Asia

More than 50 young children in Cambodia died in spring 2012 for unknown reasons, but laboratory testing of samples available from a limited number of those children came back positive for Enterovirus 71. That virus, which can cause HFMD, is known to cause severe complications among some people who contract the disease. But health officials concluded that poor baseline health and then incorrect treatment using steroids helped exacerbate their condition, helping lead to the deaths.

Antibiotic resistance is a growing global health problem

Over decades, bacteria have grown increasingly resistant to antibiotics. This resistance now causes an estimated 1.27 million deaths each year and is associated with nearly 5 million deaths worldwide, according to the World Health Organization.

Bacteriophages—viruses that infect bacteria before multiplying within them—exist on Earth in numbers greater than all other living organisms combined.

Measles was declared eliminated in the US in 2000, meaning the country had been free of continuous disease transmission for 12 months or more.

Drug-resistant infections worldwide have increased by about 65% since 2000

Since 1990, antibiotic resistance has claimed at least one million lives annually and is projected to account for 39 million deaths between now and 2050 if current trends continue. The expanded use of antibiotics, particularly in agriculture, combined with a slowing pipeline of new drugs has led to the crisis.

Explore a technical look at the measles virus and its toll on humanity through the ages.

Measles is one of the most contagious preventable diseases—it was eliminated in the US in 2000, but it is now making a resurgence due to declining vaccination rates.

It took 14 years to deploy penicillin after its discovery

Despite its promise, US production of penicillin remained minimal in 1942—enough to treat fewer than 100 patients nationwide. Within two years, output expanded into millions of doses to supply troops for D-Day.

A heatmap showing the drop in infectious diseases post-vaccine deployment

The number of infected people, measured over 70-some years and across all 50 states and the District of Columbia, declined significantly after vaccines were introduced.

Edward Jenner, the father of vaccinations

The British physician was the first to attempt to inoculate someone from smallpox using its milder cousin, cowpox. His innovations and documentations would prove crucial to the deployment of widespread vaccinations.

A look at the 2025 measles outbreak in West Texas and surrounding areas

A measles outbreak in the summer of 2025 ultimately led to more than 900 cases and the deaths of two young children. The highly contagious virus requires vaccination rates near 95% to achieve herd immunity—the Texas outbreak spread through areas of significant mistrust of vaccines, including the area’s Mennonite community.

The COVID-19 pandemic led to a decrease in immunizations in the US and worldwide

Public health funds and resources that were diverted to COVID-19 response reduced efforts to combat polio and vaccinations for polio and other diseases declined during the pandemic, putting more people at risk for polio.

Measles cases in the US reached a 35-year high in 2026 as vaccination rates dropped.

Cholera was called the 'Blue Death'

In the mid-1800s—when John Snow identified cholera in London—the disease was known simply as the "Blue Death." That's because blood would thicken in patients' veins when they were struggling with extreme dehydration. As a result, their skin would turn a blueish hue as their blood was starved of oxygen.

Live virus vaccines predated polio—that's how we vaccinate against smallpox

Since 1796, smallpox vaccines have used a live poxvirus related to smallpox. Yellow fever vaccines have used a live weakened form of the virus responsible for yellow fever since 1937.

In the 19th century, ice-cream-related illnesses were somewhat regular in America thanks to vendors' poor hygienic practices.

Listen to how the 1902 'poison squad' experiments changed food safety in America

As part of government research, a group of young men were paid to eat standard American food—replete with food additives like borax and formaldehyde—which revealed the dangers of unregulated food. The work was led by the first FDA commissioner, Harvey Wiley, who helped end the "century of the great stomachache."

Superbugs could claim 1.9 million lives per year by 2050

The increased use of antibiotics combined with an aging population, is projected to result in an almost 50% increase in global deaths from antimicrobial resistance each year. At the same time, antibiotic use for livestock is expected to increase by 30% over the same time frame.

Measles attacks the body's immune system, leaving it vulnerable to secondary complications.

Wolbachia: the bacteria that could eliminate dengue fever

Dengue fever, transmitted by mosquitoes, kills more people annually than all types of natural disasters combined. However, mosquitoes that host Wolbachia bacterium have their ability to transmit the virus naturally suppressed, offering a route to eliminating nearly 25,000 deaths annually.

Play 17th-century death roulette

Before modern science and medicine, death was much harder to escape. Using real mortality records from London's Dreadful Visitation–a collection of all the Bills of Mortality from 1665–this interactive game gives you an idea of what may have possibly killed you during the Great Plague. Grow your appreciation for life today as you stumble upon causes of death like “livergrown” and “drowned at St. Katharine’s by the Tower”.

HFMD was first reported in 1957 in New Zealand

The first clinical report involved eight kids with the characteristic sores in New Zealand, and then in the years that followed there were dozens more cases there and also reports of outbreaks in England and Scotland, among other settings, including the US.

A timeline of major pandemics from 1899–2025

Modern pandemics have been defined by the race between globalization (which increases risk) and the development of new medicines. The Great Influenza epidemic claimed some 50 million lives, and the COVID-19 pandemic killed more than 7 million. In between, diseases like Ebola, cholera, AIDS, and more have devastated communities.

Penicillin production was just behind the atom bomb in wartime priorities

By 1943, the US War Department made penicillin its second-highest priority—just after the Manhattan Project. Producing enough of the antibiotic for the D-Day invasion became a central mission of Allied science and industry.

The history of germ theory, which explains that illnesses are caused by microorganisms

For centuries, the miasma theory, which held that illnesses were caused by clouds of "bad air" produced by decaying organic matter, was the accepted explanation for the spread of disease. The development of microscopes and the subsequent technology to isolate bacteria and test disease spread in mice greatly contributed to contagionists overturning miasmatists.

Most Americans are now dying at home, reversing 20th century trends

For most of the 21st and 20th centuries most Americans died in hospital settings. But in 2016, home-based deaths overtook hospitals; most Americans are now dying at home, likely fueled by individual preferences to die at home or to receive at-home palliative care.

Most penicillin allergy diagnoses are wrong, leading to costlier, less effective treatments and contributing to the growing problem of antibiotic resistance.

Two-thirds of soldier deaths during the war were due to disease

Roughly two-thirds of all Civil War deaths resulted from disease rather than battle. Poor sanitation, contaminated water, and limited medical knowledge made camps breeding grounds for dysentery, typhoid, and other deadly infections.

How the 1918 pandemic spurred developments in virology and vaccines

This article provides an in-depth historical account of the 1918 Spanish Flu pandemic, including its impact on the global population and how its occurrence spurred significant advancements in the study of viruses—laying the groundwork for the...

Child mortality rates since ancient Rome

One of the great achievements of modern humanity has been the sea change in child mortality rates—the chance that a newborn eventually lives past puberty. For thousands of years, children had a 50% chance of not entering adulthood. About 300 years...

The 1957 and 1968 influenza pandemics caused millions of deaths worldwide

The 1957 H2N2 pandemic spread from East Asia, killing more than 1M globally, while the 1968 H3N2 pandemic began in Hong Kong and caused a similar toll, with both strains rapidly moving across continents.

Herd immunity works by slowing down viral transmission until a disease dies out.

More than 4,000 people died from cholera in 2023

This global health threat sickened more than half a million people in 2023 and killed 4,007 people. That's a 71% increase in deaths as compared to a year earlier. (Report only offered in PDF format.)

Robert Koch won the Nobel for his tuberculosis work, but he also pioneered cholera research

Koch was one of the first scientists to isolate the bacterium that causes cholera while investigating an outbreak in Egypt in 1883. He went on to advise about rules to control cholera outbreaks, which formed the basis of the disease control approaches and water hygiene techniques still used today.

The virus was officially described for the first time in 1789

Michael Underwood, an English physician and surgeon, was the first to describe the disorder, noting it caused disability in the lower extremities in children. Large-scale outbreaks of the disease were not observed until the late 19th century.

Vector-borne diseases kill more than 700,000 people globally each year—and are growing

The diseases with the greatest potential to spread widely aren't the ones that quickly kill human hosts. Instead, the best hosts or reservoirs for vector-borne diseases would be chronically ill over the long term, increasing the likelihood that the pathogen could be transmitted to others.

Europeans' arrival to America brought disease to Indigenous populations

Indigenous people lived in the Americas for centuries before the arrival of the first Europeans in the 15th century. Their arrival was disastrous for Native tribes; in addition to being enslaved and losing their land, they had no natural immunity to the diseases brought by colonists. Eventually, up to 95% of the Native American population was killed by illnesses including typhus, chickenpox, and cholera, an event now known as the Great Dying.