vaccinia
noun
vac·cin·ia
vak-ˈsi-nē-ə 
1
or vaccinia virus
: a poxvirus (species Vaccinia virus of the genus Orthopoxvirus) that differs from but is closely related to the viruses causing smallpox and cowpox and that includes a strain used in making vaccines against smallpox
2
: a reaction to smallpox vaccine prepared from live vaccinia virus that may involve a rash, fever, headache, and body pain
Examples of vaccinia in a Sentence
Recent Examples on the Web
Regulators in Nigeria have recently approved the Bavarian Nordic vaccine, and the DRC’s Ministry of Health has endorsed use of both weakened vaccinia products.
—
Byjon Cohen, science.org, 19 Apr. 2024
The vaccinia of today is in fact capable of infecting multiple species.
—Sarah Zhang, The Atlantic, 26 Aug. 2022
Generalized or widespread vaccinia infection can also occur.
—Tom Inglesby, STAT, 12 Aug. 2022
If someone gets severely ill, the US CDC has said that two other treatments—a monoclonal antibody called vaccinia immune globulin and an antiviral called cidofovir—can be used.
—David Cox, WIRED, 27 July 2022
In vaccinia viruses, these proteins have been shown to suppress early innate immune responses to promote viral replication.
—William A. Haseltine, Forbes, 6 June 2022
Older smallpox vaccines used a form of the vaccinia that could replicate, creating the risk of infection from the vaccine itself.
—Denise Roland, WSJ, 24 May 2022
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Byjon Cohen, science.org, 19 Apr. 2024
The vaccinia of today is in fact capable of infecting multiple species.
—Sarah Zhang, The Atlantic, 26 Aug. 2022
Generalized or widespread vaccinia infection can also occur.
—Tom Inglesby, STAT, 12 Aug. 2022
If someone gets severely ill, the US CDC has said that two other treatments—a monoclonal antibody called vaccinia immune globulin and an antiviral called cidofovir—can be used.
—David Cox, WIRED, 27 July 2022
In vaccinia viruses, these proteins have been shown to suppress early innate immune responses to promote viral replication.
—William A. Haseltine, Forbes, 6 June 2022
Older smallpox vaccines used a form of the vaccinia that could replicate, creating the risk of infection from the vaccine itself.
—Denise Roland, WSJ, 24 May 2022
Cite this Entry
“Vaccinia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/vaccinia. Accessed 3 Nov. 2025.
Copy CitationMedical Definition
vaccinia
noun
vac·cin·ia
vak-ˈsin-ē-ə
1
2
or vaccinia virus
: a poxvirus of the genus Orthopoxvirus (species Vaccinia virus) that differs from but is closely related to the viruses causing smallpox and cowpox and that includes a strain of uncertain natural origin used in making vaccines against smallpox
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