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== Vaccinia ==
==Vaccinia==


[[File:Vaccinia_virus_PHIL_2143_lores.jpg|thumb|right|Electron micrograph of the Vaccinia virus]]
[[File:Vaccinia_virus_PHIL_2143_lores.jpg|thumb|right|Electron micrograph of the Vaccinia virus]]


'''Vaccinia''' is a virus that belongs to the [[Poxviridae]] family, which includes other notable viruses such as [[smallpox]] and [[cowpox]]. It is best known for its role in the [[smallpox vaccine]], which led to the eradication of smallpox in 1980.
'''Vaccinia''' is a virus belonging to the [[Poxviridae]] family, which is used as a live virus vaccine for the prevention of [[smallpox]]. It is a member of the [[Orthopoxvirus]] genus, which also includes the [[variola virus]] (the causative agent of smallpox), the [[cowpox virus]], and the [[monkeypox virus]]. Vaccinia virus is notable for its role in the successful eradication of smallpox, a major achievement in public health.


== History ==
==Structure and Genetics==


The use of vaccinia virus in vaccination dates back to the late 18th century when [[Edward Jenner]] discovered that milkmaids who had contracted cowpox were immune to smallpox. Jenner used material from cowpox lesions to inoculate people, a practice that eventually evolved into the use of vaccinia virus.
Vaccinia virus is a large, complex, enveloped virus with a linear double-stranded [[DNA]] genome. The genome is approximately 190 kilobase pairs in length and encodes for around 200 proteins. The virus has a complex structure with a biconcave core and lateral bodies, which are thought to contain enzymes essential for the early stages of infection.


== Characteristics ==
==Life Cycle==


Vaccinia virus is a large, complex, enveloped virus with a linear double-stranded [[DNA]] genome. It replicates in the [[cytoplasm]] of host cells, unlike most DNA viruses that replicate in the [[nucleus]].
The life cycle of the vaccinia virus begins with attachment to the host cell surface, followed by entry into the cell. Once inside, the virus uncoats and releases its DNA into the cytoplasm. Unlike many other DNA viruses, vaccinia replicates entirely in the cytoplasm of the host cell. The virus uses its own machinery to transcribe and replicate its DNA, producing viral proteins and assembling new virions. These new virions are then released from the host cell to infect other cells.


== Use in Vaccination ==
==Use in Vaccination==


[[File:Smallpox_vaccine_site.jpg|thumb|right|A smallpox vaccination site on the arm]]
[[File:Smallpox_vaccine_site.jpg|thumb|right|A smallpox vaccination site on the arm]]


Vaccinia virus is used in the smallpox vaccine because it provides immunity against smallpox without causing the disease itself. The vaccine is administered using a bifurcated needle that pricks the skin multiple times, creating a small lesion that heals over time.
Vaccinia virus is used in the smallpox vaccine, which was the first successful vaccine to be developed. The vaccine is administered by scarification, a method that involves pricking the skin with a bifurcated needle that has been dipped in the vaccine solution. This method creates a localized infection that induces immunity to smallpox.


== Modern Applications ==
The use of vaccinia virus in vaccination led to the global eradication of smallpox, declared by the [[World Health Organization]] in 1980. The vaccine is still used today for certain high-risk groups, such as laboratory workers who handle orthopoxviruses and military personnel.


In addition to its historical use in smallpox vaccination, vaccinia virus is being explored as a vector for delivering [[genes]] in [[gene therapy]] and as a platform for developing vaccines against other infectious diseases.
==Safety and Side Effects==


== Safety and Side Effects ==
While the smallpox vaccine is generally safe, it can cause side effects, particularly in individuals with weakened immune systems or certain skin conditions. Common side effects include fever, fatigue, and a localized rash at the site of vaccination. More serious complications, such as [[eczema vaccinatum]], [[progressive vaccinia]], and [[postvaccinal encephalitis]], are rare but can occur.


While the smallpox vaccine is generally safe, it can cause side effects, particularly in individuals with weakened immune systems. Common side effects include mild fever and rash, while more serious complications are rare.
==Research and Applications==


== Related Pages ==
Vaccinia virus is also used as a tool in [[biotechnology]] and [[genetic engineering]]. Its ability to accommodate large foreign DNA sequences makes it an attractive vector for vaccine development against other infectious diseases and for cancer immunotherapy. Researchers are exploring its use in developing vaccines for diseases such as [[HIV/AIDS]], [[influenza]], and [[cancer]].
 
==Related Pages==


* [[Smallpox]]
* [[Smallpox]]
* [[Edward Jenner]]
* [[Poxviridae]]
* [[Poxviridae]]
 
* [[Orthopoxvirus]]
== References ==
* [[Variola virus]]
 
* [[Cowpox]]
* Fenner, F., Henderson, D. A., Arita, I., Jezek, Z., & Ladnyi, I. D. (1988). ''Smallpox and its Eradication''. Geneva: World Health Organization.
* [[Monkeypox]]
* Moss, B. (2001). "Poxviridae: The Viruses and Their Replication." In D. M. Knipe & P. M. Howley (Eds.), ''Fields Virology'' (4th ed., pp. 2849-2883). Philadelphia: Lippincott Williams & Wilkins.
 
[[File:Smallpox_vaccine_USP.jpg|thumb|right|Vial of smallpox vaccine]]
 
{{Smallpox}}


[[Category:Vaccines]]
[[Category:Vaccines]]
[[Category:Poxviruses]]
[[Category:Orthopoxviruses]]
<gallery>
[[Category:Smallpox]]
File:Vaccinia_virus_PHIL_2143_lores.jpg|Vaccinia virus
File:Smallpox_vaccine_site.jpg|Smallpox vaccine site
File:Smallpox_vaccine_USP.jpg|Smallpox vaccine
</gallery>
== Vaccinia ==
<gallery>
File:Vaccinia virus PHIL 2143 lores.jpg|Vaccinia virus
File:Smallpox vaccine site.jpg|Smallpox vaccine site
File:Smallpox vaccine USP.jpg|Smallpox vaccine USP
</gallery>

Revision as of 11:44, 23 March 2025

Vaccinia

Electron micrograph of the Vaccinia virus

Vaccinia is a virus belonging to the Poxviridae family, which is used as a live virus vaccine for the prevention of smallpox. It is a member of the Orthopoxvirus genus, which also includes the variola virus (the causative agent of smallpox), the cowpox virus, and the monkeypox virus. Vaccinia virus is notable for its role in the successful eradication of smallpox, a major achievement in public health.

Structure and Genetics

Vaccinia virus is a large, complex, enveloped virus with a linear double-stranded DNA genome. The genome is approximately 190 kilobase pairs in length and encodes for around 200 proteins. The virus has a complex structure with a biconcave core and lateral bodies, which are thought to contain enzymes essential for the early stages of infection.

Life Cycle

The life cycle of the vaccinia virus begins with attachment to the host cell surface, followed by entry into the cell. Once inside, the virus uncoats and releases its DNA into the cytoplasm. Unlike many other DNA viruses, vaccinia replicates entirely in the cytoplasm of the host cell. The virus uses its own machinery to transcribe and replicate its DNA, producing viral proteins and assembling new virions. These new virions are then released from the host cell to infect other cells.

Use in Vaccination

A smallpox vaccination site on the arm

Vaccinia virus is used in the smallpox vaccine, which was the first successful vaccine to be developed. The vaccine is administered by scarification, a method that involves pricking the skin with a bifurcated needle that has been dipped in the vaccine solution. This method creates a localized infection that induces immunity to smallpox.

The use of vaccinia virus in vaccination led to the global eradication of smallpox, declared by the World Health Organization in 1980. The vaccine is still used today for certain high-risk groups, such as laboratory workers who handle orthopoxviruses and military personnel.

Safety and Side Effects

While the smallpox vaccine is generally safe, it can cause side effects, particularly in individuals with weakened immune systems or certain skin conditions. Common side effects include fever, fatigue, and a localized rash at the site of vaccination. More serious complications, such as eczema vaccinatum, progressive vaccinia, and postvaccinal encephalitis, are rare but can occur.

Research and Applications

Vaccinia virus is also used as a tool in biotechnology and genetic engineering. Its ability to accommodate large foreign DNA sequences makes it an attractive vector for vaccine development against other infectious diseases and for cancer immunotherapy. Researchers are exploring its use in developing vaccines for diseases such as HIV/AIDS, influenza, and cancer.

Related Pages