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

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.

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.

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...

A 1954 outbreak at a Boston boarding school allowed scientists to isolate the measles virus

While measles was described as early as the 9th century, humanity lacked the medical technology to fight the disease until the mid-20th century. Vaccine development from the Boston outbreak in the 1960s and 1970s led to one of the most effective inoculation campaigns in history.

An overview on germ theory, the crucial framework developed by Louis Pasteur

Germ theory of disease is based on the concept that many diseases are caused by infections with microorganisms, typically only visualized under high magnification. Read this general overview to understand the basic framework which allowed for development of vaccines.

The flu vaccine has evolved alongside discoveries of new virus strains

After influenza B was identified in 1940, researchers created a two-strain vaccine by 1942. The WHO later built a global surveillance system to track mutations, enabling vaccines to be updated annually to target the strains most likely to circulate.

Breaking down the different types of vaccine technologies

There are several different types of vaccines. Each type is designed to teach your immune system how to fight off germs—and the serious diseases they cause. This short overview breaks down the differences between the types.

Diphtheria was once a leading childhood killer before antibiotics and vaccines

In 18th- and 19th-century outbreaks, some New England families lost as many as eight children to diphtheria, and fatality rates in hospitals often topped 60%. The invention of antitoxins, penicillin, and vaccines dramatically reduced deaths.

What is vaccination? The World Health Org explains

Read up on the basics of vaccinations with this 101 from the World Health Organization, the public health arm of the United Nations.

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.

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...

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.

Explore 3D models of some of the most dangerous viruses

Everyone has come in contact with common viruses—typically something like influenza (the common flu)—but sometimes they encounter more dangerous strains. While we're familiar with the symptoms that manifest, it wasn't until the advent of advanced microscopy that scientists could pin down the exact structure and behavior of various viruses.

Using mosquitoes to vaccinate bats could curb the spread of deadly diseases

Researchers in China tested a transmissible rabies vaccine in the lab by feeding mosquitoes blood containing the vaccine and observing what happened to bats when they were either bitten by the mosquitoes or fed on them. The bats developed antibodies against rabies and survived subsequent rabies infection. (Some users may encounter a paywall.)

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

See the evolution of Ebola vaccine and treatment development.

Modern antivirus software searches for malicious behavior alongside malicious code

The first viral infections were identified by comparing the computer code of programs and files with a database of known virus codes, a method known as signature detection. The ongoing creation of new malware made databases continuously outdated, leading to the development of systems that detect patterns consistent with known viral activity.

In 1892, two scientists purposefully infected themselves with cholera bacteria

When they became ill—one with mild diarrhea and the other with severe cholera—researchers pointed to that as proof that the pathogen caused the disease.

A history of vaccine rollouts

History tells us the public will tolerate risk of harm from a vaccine if their fear of the disease exceeds their fear of the vaccine.

One doctor argued vampires were based on a real disease

At a conference in 1985, Canadian biochemist David H. Dolphin posited that stories of vampires and werewolves had a real-world origin. He argued that porphyria could have caused sufferers to seek out blood, as well as experience light sensitivity and an aversion to garlic. More than one article in the 1990s discredited this take.

Six of history's most unethical human experiments, from deliberate flu exposure to withholding syphilis treatment

Some of the progress made in mental health treatment, vaccines, blood transfusions, and more came about before the advent of consent and ethics committees, resulting in serious physical and psychological harm that participants in studies were not even anticipating.

Penicillin’s discoverer predicted antibiotic resistance

Alexander Fleming’s discovery of penicillin revolutionized modern medicine. But the same man who pioneered the development of antibiotics also recognized that bacteria could make sntibiotics obsolete if they were used irresponsibly. This story sheds light on Fleming’s discovery—and on his prophetic warning about antibiotic resistance.

Measles infection can cause long-term immune system “amnesia”

The measles virus attacks the body's immune system, including preying on T and B cells in the lymphatic system. These cells hold memories of past infections, which can be degraded as the virus destroys them. This leaves patients susceptible to other infections for a year or longer.

Certain vaccinations may be more effective when given around the middle of the day

A 2023 analysis of the health records of more than 1.5 million people in Israel suggests that COVID-19 vaccines may be more effective when received around the middle of the day. Separate early research also suggests there may be similar trends for influenza vaccines.

Lyme disease-causing bacteria predate any suspected biological weapons testing

Borrelia bacteria existed long before any US biological weapons program—or human presence in North America. One study comparing genomes of the bacteria behind Lyme disease collected samples of the bacteria over three decades and calculated that the bacterium has been in North America longer than humans, at least 60,000 years. Other work found related bacteria preserved in amber from millions of years ago.

Marburg virus, related to Ebola, is also extremely deadly, and has no available vaccine.

Experimental hantavirus vaccines and therapies, still under development, have long been funded by the US military.

IVF was long considered controversial and ethically dubious

In spite of its wide acceptance as a form of reproductive assistance today, and its role in helping millions of people have children, in vitro fertilization was once considered a controversial threat to society. One magazine went as far as to describe the procedure as "the biggest threat since the atom bomb."

The birth of the multivitamin

In 1912, biochemist Kazimierz Funk, often anglicized as Casimir Funk, proposed that there existed an essential nutrient in food that could prevent deficiency diseases, such as scurvy or rickets. This article explores the origin of the multivitamin, an invention that has garnished...

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Elk Cloner, the first computer virus to spread in public, was written as a practical joke by Richard Skrenta, a Pittsburgh high school student.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

This poison ivy knowledge quiz—accompanied by photos of the plant's varied forms—may help you identify this common rash-inducing growth.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

A researcher recently discovered an interview from 1967 between groundbreaking journalist Joan Didion and the Grateful Dead, years before the band became an institution.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

A century of Billboard issues documenting the evolution of popular music.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.