Patient Zero: The narrative of outbreaks

It’s time to come up with a different name.

A person is dressed as a plague doctor against a bright pink backdrop.
Photo: Peter Macdiarmid / Staff (Getty Images)

A viral accident

The term “Patient Zero” was created by mistake.

In 1984, the US Centers for Disease Control and Prevention (CDC) was conducting an AIDS cluster study, and nicknamed one participant, Gaétan Dugas, Patient “O,” which stood for “out of California.” Later, other researchers misinterpreted (pdf) the “O” as “0,” and assumed he was “Patient Zero” in the North American AIDS epidemic. A subsequent media frenzy popularized the term.

Not only was the “Patient Zero” designation false, and devastating for Dugas, but it also gave rise to an imprecise, often inflammatory label that is still in circulation to this day.


“Patient Zero’’ has surged in use during the covid pandemic, especially in media coverage. It’s been deployed as an attention-grabbing phrase, lending a sense of investigative mystery to stories. But the problem is, epidemiology is not a whodunnit. And the scientized-sounding “Patient Zero” more often than not serves as a narrative smokescreen for placing blame, rather than illuminating the realities of how diseases spread.

In the words of University of Cambridge professor Richard McKay, “Writing of a ‘patient zero’ is a damaging red herring that distracts from constructive efforts to contain the epidemic. Let’s wash our hands of this toxic phrase.”


Let’s take a closer look at the indicators that really matter in understanding pandemics, and how the narrative of outbreaks is best presented to the public.

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A woman wears an old fashioned flu mask with a tube coming out of it.
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What does it even mean?

One of the issues with the term “Patient Zero” is that its meaning is unclear. Does it refer to the first ever case of a disease? The first documented case? The first case in a particular population? More specific alternatives exist.


📍 Primary case: The individual(s) who brings a disease to a particular population.

👁️ Index case: The first case of a disease noticed by investigators within a particular population (e.g. a school, a town, a country), alerting them to an outbreak.


1️⃣ Alpha or Ur case: The absolute first ever case to happen in the human population, almost always unknown.

🔀 Crossover case: The first case of a disease transmitted from an animal to a human, a term that could be used for zoonotic diseases like coronaviruses, also often unknown.


The numbers do lie

“For many outbreaks, the primary case will never be known,” writes Johan Giesecke, professor emeritus at the Karolinska Institute in Stockholm. In rare cases, the index and primary case can be the same, but usually it’s the index case that is the crucial piece of information health authorities need to mobilize an effective response to the spread of a disease, and also to trace the virus’s genetic lineage.


Primary cases, if known, can also help public health officials understand the “chronology” of a disease, but when it comes to the term “Patient Zero,” there is no scientific definition. It’s a narrative that frames the disease as a villain, and health authorities as valiant heroes, engaged in a warlike battle against it.

Therein lies that usage’s danger, as Priscilla Wald writes in Contagious: Cultures, Carriers, and the Outbreak Narrative: “the mythic frame of the outbreak narrative subtly complements the more explicitly stigmatizing terms through which landscapes and people are portrayed as dangers, dirty, and diseased.”


It’s easy to seek out scapegoats in the face of a perceived threat. But this narrative does nothing to address global health inequity or social justice, nor does it promote public understanding of epidemiology. “Patient Zero” is part of a dehumanizing, fear-based story that is damaging to epidemic response, especially in an age when pandemic response requires global cooperation. Disease, after all, is not an individual incident—it interconnects and involves all of us.


Below is a Google trends graph showing United States web search interest in the term “Patient Zero” from August 1, 2019 to August 1, 2022. Google scores level of interest from 0-100, where 0 means there is not enough data and 100 means peak popularity. In March 2020, around the time the WHO declared the coronavirus outbreak a pandemic, the term “Patient Zero” reached peak popularity, while current popularity (Aug. 2022) is at a 6.

A line graph showing google searches for patient zero. They went up in March 2020 after the start of the covid-19 pandemic.
Screenshot: Google Trends


“The history of diseases has always been, in part, that someone needs to be blamed.”


Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases and chief medical advisor to the president

Bill Gates is pictured in front of a microphone and he's pointing at something with his mouth open.
Photo: Timm Schamberger / Staff (Getty Images)

Which person was falsely labeled “Patient Zero” during covid?

A: Maatje Benassi

B: Bill Gates

C: Gilbert Arenas

D: Stanley Tucci

Find the answer at the bottom!

And by the way, in some editions of last week’s Direct Indexing Obsession, we mistakenly said the correct answer to the quiz was A. Capital-gain gardening, which is a term we made up and clearly got too excited about. The answer was of course B. Tax-loss harvesting. 


Brief history

c. 541 CE: The Justinianic plague, the first known outbreak of the bubonic plague in western Eurasia, spreads across the Byzantine empire.


1346: The Black Plague emerges in Mongolia, with a new strain entering Europe through Genoa, Italy in 1348.

1504: Europeans bring syphilis to China via Guangzhou, where it is named “plum tree poison.”


1619: Charles de Lorme, a court physician to King Louis XII of France, creates a beaked plague costume that we now know as the “plague doctor” outfit.

1796: The discovery that an infection of the milder cowpox protects against smallpox sets in motion the creation of the oldest known vaccine, which contributed to the eradication of the disease in 1980.


1861: Louis Pasteur publishes his landmark work on germ theory.

1918: The influenza virus spreads worldwide, killing an estimated 50 million people, becoming the deadliest known flu in history.


1928: Alexander Fleming discovers penicillin in a moldy petri dish, leading to the world’s first mass produced antibiotic.

1981: The HIV/AIDS epidemic begins, with a reported 337 cases of individuals with “severe immunodeficiency” by December of that year.


2002: SARS, a coronavirus believed to have originated in animals, begins spreading across China and becomes the first pandemic of the 21st century.

2020: The first covid-19 vaccine is administered outside of a clinical trial on Dec. 8, nearly a year after the novel coronavirus SARS‑CoV‑2 was identified in Wuhan, China, becoming the fastest vaccine ever created.


Fun fact

In order to spread awareness about infectious diseases, Taiwan’s Centers for Disease Control turned them into villainous anime characters.


A still image showing two profiles of a person, Typhoid Mary, with their hair up in a large bun.
Screenshot: YouTube (Other)

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Mary Mallon, a.k.a. “Typhoid Mary,” was the first identified asymptomatic carrier of typhoid fever in the US. Her story not only shows the development of modern contact tracing, but also raises ethical questions surrounding public health and safety protocols.


Take me down this 🐰 hole!

In 1854, the Soho district of London became the center of a major cholera outbreak that in two weeks killed more than 550 people. An English physician named John Snow conducted an investigation into the outbreak’s origins—that study would become a defining moment in the development of epidemiology.


At the time, there were two competing schools of thought (pdf) on the spread of disease: miasma theory and germ theory. Miasma theory, a now obsolete idea that originated as early as ancient Greece, posited that disease spread through “bad air” (pdf) be it from a rotting animal, molds, or dust particles. Germ theory, the current scientific consensus on how disease spreads, stated that illnesses originate in tiny organisms called pathogens.

Snow was skeptical of miasma theory and hypothesized that cholera was a germ being transmitted through a contaminated, shared water source. He observed that almost all of the cholera deaths happened not far from a drinking water pump on Broad Street (now Broadwick Street). Through interviews, he found that those who collected their water from nearby wells instead had not been affected. Snow concluded that the pump had contaminated water that was spreading the disease, and alerted authorities to have it removed.


The outbreak ceased. Snow’s findings prompted a response from lawmakers to clean London’s water and sewage systems. Also, his investigation proved that cholera is waterborne, providing strong backing for germ theory and creating a blueprint for contemporary public health investigations.

People dressed as zombies are making their way toward the camera.
Photo: Philip Fong / Contributor (Getty Images)


Would you survive Patient Zero, the 2018 zombie apocalypse movie?

Take our poll, and be careful out there.

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🤔 What did you think of today’s email?

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Today’s email was written by Julia Malleck (middling zombie apocalypse skills) and edited by Susan Howson (will never go near a water pump) and Sofia Lotto Persio (bad at being patient).


The correct answer to the quiz is A. Maatje Benassi. The US Army reservist became a conspiracy theory target, blamed for bringing the disease from China after participating in the 2019 Military World Games in Wuhan. As for the other options: There is a conspiracy theory that Bill Gates created covid, Stanley Tucci was in a film called Patient Zero (2018), and former NBA basketball player Gilbert Arenas is nicknamed Agent Zero.