vaccine

noun

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vac·cine | \ vak-ˈsēn

, ˈvak-ˌsēn \

plural vaccines

Definition of vaccine

1 : a preparation that is administered (as by injection) to stimulate the body's immune response against a specific infectious agent or disease: such as

a : an antigenic preparation of a typically inactivated or attenuated (see attenuated sense 2) pathogenic agent (such as a bacterium or virus) or one of its components or products (such as a protein or toxin) a trivalent influenza vaccine oral polio vaccine Many vaccines are made from the virus itself, either weakened or killed, which will induce antibodies to bind and kill a live virus. Measles vaccines are just that, weakened (or attenuated) measles viruses.— Ann Finkbeiner et al. … a tetanus toxoid-containing vaccine might be recommended for wound management in a pregnant woman if [greater than or equal to] 5 years have elapsed … .— Mark Sawyer et al. In addition the subunit used in a vaccine must be carefully chosen, because not all components of a pathogen represent beneficial immunological targets.— Thomas J. Matthews and Dani P. Bolognesi

b : a preparation of genetic material (such as a strand of synthesized messenger RNA) that is used by the cells of the body to produce an antigenic substance (such as a fragment of virus spike protein) … Moderna's coronavirus vaccine … works by injecting a small piece of mRNA from the coronavirus that codes for the virus' spike protein. … mRNA vaccine spurs the body to produce the spike protein internally. That, in turn, triggers an immune response.— Susie Neilson et al. The revolutionary messenger RNA vaccines that are now available have been over a decade in development. … Messenger RNA enters the cell cytoplasm and produces protein from the spike of the Covid-19 virus.— Thomas F. Cozza Viral vector vaccines, another recent type of vaccine, are similar to DNA and RNA vaccines, but the virus's genetic information is housed in an attenuated virus (unrelated to the disease-causing virus) that helps to promote host cell fusion and entry.— Priya Kaur

Note: Vaccines may contain adjuvants (such as aluminum hydroxide) designed to enhance the strength and duration of the body's immune response.

2 : a preparation or immunotherapy that is used to stimulate the body's immune response against noninfectious substances, agents, or diseases The U.S. Army is also testing a ricin vaccine and has reported success in mice.— Sue Goetinck Ambrose … many of the most promising new cancer vaccines use dendritic cells to train the immune system to recognize tumor cells.— Patrick Barry

Other Words from vaccine More Example Sentences Phrases Containing vaccine Learn More About vaccine

Examples of vaccine in a Sentence

Recent Examples on the Web Despite that, vaccine hesitancy remains a major issue. — USA Today, 15 May 2022 White House press secretary Jen Psaki said Thursday the United States supported international aid efforts but doesn’t plan to share its vaccine supplies with the North. — Fox News, 15 May 2022 Indeed, 63% of the avoidable deaths in the U.S. occurred by the end of February 2021, when the vaccine rollout was just beginning and before the Delta variant became dominant. — Michael A. Stoto, STAT, 14 May 2022 Indeed, age has sometimes been a bigger risk factor than vaccine status during the pandemic. — New York Times, 14 May 2022 North Korea is not known to have imported any coronavirus vaccines -- despite being eligible for the global Covid-19 vaccine sharing program, Covax. — Nectar Gan, Gawon Bae And Helen Regan, CNN, 14 May 2022 Lawmakers still have months left in their 2021 session, but an ambitious slate of vaccine bills proposed by Democrats is on life support. — Dustin Gardiner, San Francisco Chronicle, 13 May 2022 It is also believed that the country has not administered COVID-19 vaccines to its 25 million people, having refused COVID-19 vaccines from global vaccine sharing program COVAX. — Time, 13 May 2022 Janssen vaccine are eligible for a second booster shot, according to the CDC. — Erin Prater, Fortune, 13 May 2022 See More

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

History and Etymology for vaccine

earlier, "fluid from cowpox pustules used in inoculation," noun use of vaccine "of cowpox" (in the phrases vaccine disease, vaccine matter), borrowed from New Latin vaccina (in variolae vaccinae "cowpox"), going back to Latin, feminine of vaccīnus "of or from a cow," from vacca "cow" (perhaps akin to Sanskrit vaśā "cow") + -īnus -ine entry 1; in extended sense, "preparation of organisms administered to produce immunity," in part borrowed from French vaccin, masculine derivative of vaccine "cowpox, matter from cowpox pustules," borrowed from New Latin or English

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Last Updated

17 May 2022

Cite this Entry

“Vaccine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/vaccine. Accessed 21 May. 2022.

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More Definitions for vaccine

vaccine

noun

vac·cine | \ vak-ˈsēn

, ˈvak-ˌsēn \

Kids Definition of vaccine

: a preparation containing usually killed or weakened microorganisms (as bacteria or viruses) that is given usually by injection to increase protection against a particular disease

vaccine

noun

vac·cine | \ vak-ˈsēn, ˈvak-ˌ

Medical Definition of vaccine

1 : a preparation that is administered (as by injection) to stimulate the body's immune response against a specific infectious agent or disease: such as

a : an antigenic preparation of a typically inactivated or attenuated pathogenic agent (such as a bacterium or virus) or one of its components or products (such as a protein or toxin) a trivalent influenza vaccine Extensive use of inactivated poliovirus vaccine (IPV) (starting in 1955) and live attenuated oral poliovirus vaccine (OPV) (beginning in 1961) led to a dramatic decrease in poliomyelitis incidence in the United States …— Mark A. Miller et al., The Journal of the American Medical Association … a tetanus toxoid-containing vaccine might be recommended for wound management in a pregnant woman if [greater than or equal to] 5 years have elapsed since the previous Td booster.— Mark Sawyer et al., Morbidity and Mortality Weekly Report Many vaccines are made from the virus itself, either weakened or killed, which will induce antibodies to bind and kill a live virus. Measles vaccines are just that, weakened (or attenuated) measles viruses.— Ann Finkbeiner, et al., John Hopkins Magazine

b : a preparation of genetic material (such as a strand of synthesized messenger RNA) that is used by the cells of the body to produce an antigenic substance (such as a fragment of virus spike protein) a COVID-19 vaccine The Pfizer and Moderna vaccines are messenger RNA vaccines. They contain the genetic code for making the spike protein that the SARS-CoV-2 virus uses to latch onto and invade cells. Once injected, a person's cells read the code and then produce the protein.— Sharon Kirkey, The Star Phoenix (Saskatchewan, Canada) For an mRNA vaccine, the genetic message encoding for the protein antigen needs to be effectively delivered into the cells.— Angus Liu, FiercePharma Viral vector vaccines, another recent type of vaccine, are similar to DNA and RNA vaccines, but the virus's genetic information is housed in an attenuated virus (unrelated to the disease-causing virus) that helps to promote host cell fusion and entry.— Priya Kaur, Addison County (Vermont) Independent

Note: Vaccines may contain adjuvants (such as aluminum hydroxide) designed to enhance the strength and duration of the body's immune response.

2 : a preparation or immunotherapy that is used to stimulate the body's immune response against noninfectious substances, agents, or diseases The investigational ricin vaccine, RiVax …, was effective in creating ricin-neutralizing antibodies in one of five participants given a low dose of the vaccine, four of five given an intermediate dose, and five of five receiving a high dose.— Amy Pfeiffer, Clinical Neurology News Dendritic cells play a key role in activating an immune response—whether against a foreign microbe or a damaged body cell—so many of the most promising new cancer vaccines use dendritic cells to train the immune system to recognize tumor cells.— Patrick Barry, Science News … these antigen-based cancer vaccines require gene transfer. They work best when administered to cells that are readily accessed by the immune system.— R. Michael Blaese, Scientific American