an·​ti·​vi·​ral | \ˌan-tē-ˈvī-rəl, ˌan-tī-\

Definition of antiviral 

(Entry 1 of 2)

1 medical : acting, effective, or directed against viruses an antiviral vaccine/drug

2 : used to protect a computer from viruses : antivirus antiviral software



Definition of antiviral (Entry 2 of 2)

: an antiviral agent and especially a drug antivirals used in treating influenza

Examples of antiviral in a Sentence

Recent Examples on the Web: Adjective

In the event that existing vaccines provide no protection from a particular new flu threat, antiviral medicines would at least pose a partial first line of defense against the epidemic until a vaccine could be developed. Ron Klain, Vox, "A pandemic killing tens of millions of people is a real possibility — and we are not prepared for it," 15 Oct. 2018 Development of antiviral medicines to treat patients is still in early stages, too. Emily Baumgaertner, New York Times, "High-Resolution Snapshot of Zika Virus Reveals Clues to Fighting It," 26 June 2018 Four experimental treatments for Ebola were sent to the region: ZMapp, which was tried in West Africa; GS-5734, an antiviral drug; and two monoclonal antibodies, REGN-EB3 and Ma b114. New York Times, "Ebola Outbreak in Central Africa Is ‘Largely Contained’," 28 June 2018 Influenza viruses developed resistance long ago to the first two antiviral flu drugs, amantadine and rimantadine. NBC News, "New, fast-acting flu drug gets priority FDA review," 26 June 2018 The National Institute on Aging, which helped fund the new research, is working to back another study to test the effects of antiviral drugs on people in the early stages of Alzheimer’s with high levels of herpes virus in their brains. Fiza Pirani, ajc, "Herpes virus may be linked to Alzheimer’s, study suggests," 22 June 2018 But in people treated with antiviral drugs, that risk was reduced by 90 percent. Sharon Begley, STAT, "New study supports long-dismissed idea: Herpes viruses could play role in Alzheimer’s," 21 June 2018 Also among the experimental treatments that have shown some promise is favipiravir, a broad-spectrum antiviral drug, one that is intended to treat a range of viruses. Susan Scutti, CNN, "Ebola 101: Answers to your questions about causes, symptoms, transmission and treatments," 25 May 2018 There is currently no antiviral drug for Ebola licensed by the US Food and Drug Administration. Elise Takahama,, "MIT chemists hope manmade ‘xenoproteins’ can help battle diseases like Ebola," 21 May 2018

Recent Examples on the Web: Noun

But certain people in high-risk groups — young children, pregnant women, people over age 65, people with other chronic diseases — may want to seek medical attention and antivirals like Tamiflu. Julia Belluz, Vox, "80,000 Americans died of the flu last year. Get your flu shot.," 27 Sep. 2018 The patients were treated with the flu vaccine and antivirals, reported the CDC in a statement. Rachel Becker, The Verge, "CDC investigates two more flights that landed with coughing passengers," 6 Sep. 2018 The experimental treatment can tackle various flu varieties such as H7N9 and H5N1, according to Genentech, and behaves in a different way from other antivirals. Sy Mukherjee, Fortune, "This New Single Dose Flu Drug Could Be Coming to the U.S. Before the Next Flu Season," 28 June 2018 The company, which is not abandoning research into tropical diseases such as malaria, is looking to license its early-stage products and stressed that its Sandoz generics unit continues to manufacture and sell antibiotics and antivirals. Ed Silverman, STAT, "Pharmalittle: Most drug price hikes occurred before Azar arrived; Novartis abandons antibiotics," 12 July 2018 There are antibiotics, including the powerful medication Ciprofloxacin, vaccines for smallpox and anthrax and antivirals for a deadly influenza pandemic. James Hohmann, Washington Post, "The Daily 202: Mick Mulvaney’s confession highlights the corrosive influence of money in politics," 25 Apr. 2018 But the development of more effective antivirals for people who have already been infected is a key element of fighting influenza, too. Sy Mukherjee, Fortune, "Brainstorm Health: 24 Hour Flu Killer, Scott Walker and Obamacare, Drug Regulation Under Trump," 23 Feb. 2018 Researchers are going to be taking data on this deployment of rVSV-Zebov, as well as looking at other even more experimental therapies—the antibody drug ZMapp and the antivirals favipiravir and GS-5734. Adam Rogers, WIRED, "The Wild Logistical Ride of the Ebola Vaccine's High-Tech Thermos," 29 May 2018 Inside, there are antibiotics, vaccines for smallpox and anthrax, and antivirals for a deadly flu pandemic. Washington Post, "The Health 202: Forget the VA. It's not clear Ronny Jackson can do his current job.," 25 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'antiviral.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of antiviral


1929, in the meaning defined at sense 1


1959, in the meaning defined above

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Last Updated

21 Nov 2018

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The first known use of antiviral was in 1929

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More Definitions for antiviral


an·​ti·​vi·​ral | \-ˈvi-rəl \
variants: also antivirus \-​rəs \

Medical Definition of antiviral 

(Entry 1 of 2)

: acting, effective, or directed against viruses antiviral drugs



Medical Definition of antiviral (Entry 2 of 2)

: an antiviral agent and especially a drug

More from Merriam-Webster on antiviral

Spanish Central: Translation of antiviral

Comments on antiviral

What made you want to look up antiviral? Please tell us where you read or heard it (including the quote, if possible).


to make faulty or ineffective

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