patient zero
noun
plural patient zeros also patient zeroes
: a person identified as the first to become infected with an illness or disease in an outbreak
The quest to find patient zero, the first person to contract the new virus, has revealed the first known case occurred in Wuhan …—
Susan Dunlevy
Susan Dunlevy
especially
: a person documented as being the first known case of a communicable disease in a particular population or region
Stay out of hospital emergency rooms unless you are severely ill or injured. For now, it's the likeliest place to catch coronavirus. Anyone unknowingly suffering from coronavirus is likely to go there. That's what "patient zero" in Italy did. —Betsy McCaughey
Betsy McCaughey The 26-year-old nurse contracted Ebola after volunteering to care for U.S. 'patient zero' Thomas Eric Duncan, who tragically died on October 10 from the deadly disease. —Ashley Collman et al.
compare index case sense 2
Ashley Collman et al. Examples of patient zero in a Sentence
Recent Examples on the Web
Bass guitarists from Victor Wooten, all the technicians, Stanley Clarke — Larry Graham is patient zero of that.
—Brian Hiatt, Rolling Stone, 10 June 2025
The old playbook — detecting problems at a patient zero (i.e. first signs of sickness, or in security terms the first signs of a vulnerability) and then reacting often won't cut it anymore.
—Adrian Bridgwater, Forbes, 18 Dec. 2024
So, naturally, when one of Jacob’s students becomes patient zero of a ringworm outbreak at Abbott, the touchy-feely bubble of the early stage of Gregory’s relationship with Janine quickly bursts, becoming their first real speed bump since going public.
—Ile-Ife Okantah, Vulture, 16 Oct. 2024
Where to watch Black Mirror: Netflix 02 of 21
Broadchurch (2013–2017)
Olivia Colman and David Tennant star as dower detectives investigating the murder of a young boy in this British series, which is essentially patient zero for every crime-busting Britbox show from the last decade.
—Declan Gallagher, EW.com, 29 Sep. 2024
Steven Soderbergh's thriller follows the quick spread of a virus that turns into a disruptive global pandemic (sound familiar?) starring Gwyneth Paltrow as the patient zero, Matt Damon as her husband, Jude Law as a conspiracy theorist and Laurence Fishburne as a Fauci-esque physician.
8.
—Brian Truitt, USA TODAY, 19 July 2024
This suggests the possibility that this worm might have originated from multiple patient zeros in different countries.
—Dan Goodin, Ars Technica, 25 Apr. 2024
McConaughey appears to be patient zero for testing the theory while living in the middle of the United States.
—Nardine Saad, Los Angeles Times, 8 Mar. 2024
That could change if the lone mule deer that tested positive in Yellowstone National Park in November becomes patient zero in a local outbreak.
—Katie Hill, Outdoor Life, 4 Jan. 2024
Examples are automatically compiled from online sources to
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Brian Hiatt, Rolling Stone, 10 June 2025
The old playbook — detecting problems at a patient zero (i.e. first signs of sickness, or in security terms the first signs of a vulnerability) and then reacting often won't cut it anymore.
—Adrian Bridgwater, Forbes, 18 Dec. 2024
So, naturally, when one of Jacob’s students becomes patient zero of a ringworm outbreak at Abbott, the touchy-feely bubble of the early stage of Gregory’s relationship with Janine quickly bursts, becoming their first real speed bump since going public.
—Ile-Ife Okantah, Vulture, 16 Oct. 2024
Where to watch Black Mirror: Netflix 02 of 21
Broadchurch (2013–2017)
Olivia Colman and David Tennant star as dower detectives investigating the murder of a young boy in this British series, which is essentially patient zero for every crime-busting Britbox show from the last decade.
—Declan Gallagher, EW.com, 29 Sep. 2024
Steven Soderbergh's thriller follows the quick spread of a virus that turns into a disruptive global pandemic (sound familiar?) starring Gwyneth Paltrow as the patient zero, Matt Damon as her husband, Jude Law as a conspiracy theorist and Laurence Fishburne as a Fauci-esque physician.
8.
—Brian Truitt, USA TODAY, 19 July 2024
This suggests the possibility that this worm might have originated from multiple patient zeros in different countries.
—Dan Goodin, Ars Technica, 25 Apr. 2024
McConaughey appears to be patient zero for testing the theory while living in the middle of the United States.
—Nardine Saad, Los Angeles Times, 8 Mar. 2024
That could change if the lone mule deer that tested positive in Yellowstone National Park in November becomes patient zero in a local outbreak.
—Katie Hill, Outdoor Life, 4 Jan. 2024
Cite this Entry
“Patient zero.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/patient%20zero. Accessed 14 Jul. 2025.
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