Vaccinia

Vaccinia virus
A virions
Virus classification
(unranked):	Virus
Realm:	Varidnaviria
Kingdom:	Bamfordvirae
Phylum:	Nucleocytoviricota
Class:	Pokkesviricetes
Order:	Chitovirales
Family:	Poxviridae
Genus:	Orthopoxvirus
Species:	Vaccinia virus
Member viruses[1]
Buffalopox virus Cantagalo virus Rabbitpox virus Utrecht Vaccinia virus Ankara Vaccinia virus Copenhagen Vaccinia virus WR

Vaccinia virus (VACV or VV) is a large, complex,

In addition to the morbidity of uncomplicated primary vaccination, transfer of infection to other sites by scratching, and post-vaccinial encephalitis, other complications of vaccinia infections may be divided into the following types:^[7]: 391

• Generalized vaccinia
• Eczema vaccinatum
• Progressive vaccinia (vaccinia gangrenosum, vaccinia necrosum)
• Roseola vaccinia

Origin

Vaccinia virus is closely related to the virus that causes

Vaccinia virus is able to undergo multiplicity reactivation (MR).[13] MR is the process by which two, or more, virus genomes containing otherwise lethal damage interact within an infected cell to form a viable virus genome. Abel^[13] found that vaccinia viruses exposed to doses of UV light sufficient to prevent progeny formation when single virus particles infected host chick embryo cells, could still produce viable progeny viruses when host cells were infected by two or more of these inactivated viruses; that is, MR could occur. Kim and Sharp demonstrated MR of vaccinia virus after treatment with UV-light,^[14] nitrogen mustard,^[15] and X-rays or gamma rays.^[16] Michod et al.^[17] reviewed numerous examples of MR in different viruses, and suggested that MR is a common form of sexual interaction in viruses that provides the advantage of recombinational repair of genome damages.^{[additional citation(s) needed]}

Host resistance

Vaccinia contains within its genome genes for several proteins that give the virus resistance to interferons:

• K3L (P18378) is a protein with
  eukaryotic initiation factor 2 (eIF-2alpha). K3L protein inhibits the action of PKR, an activator of interferons.^[18]
• E3L (P21605) is another protein encoded by Vaccinia. E3L also inhibits PKR activation; and is also able to bind to double stranded RNA.^[18]
• B18R is a protein which serves as an interferon inhibitor in one of Moderna's technologies.^[19]

Use as a vaccine

Vaccinia virus infection is typically very mild and often does not cause symptoms in healthy individuals, although it may cause rash and

On September 1, 2007, the U.S. Food and Drug Administration (FDA) licensed a new vaccine ACAM2000 against smallpox which can be produced quickly upon need. Manufactured by Sanofi Pasteur, the U.S. Centers for Disease Control and Prevention stockpiled 192.5 million doses of the new vaccine (see list of common strains below).^[22]

A smallpox vaccine,

The original vaccine for smallpox, and the origin of the idea of vaccination, was Cowpox, described by Edward Jenner in 1798. The Latin term used for Cowpox was Variolae vaccinae, Jenner's own translation of "smallpox of the cow". That term lent its name to the whole idea of vaccination.^[25] When it was realized that the virus used in smallpox vaccination was not, or was no longer, the same as cowpox virus, the name 'vaccinia' was used for the virus in smallpox vaccine. (See OED.) Vaccine potency and efficacy prior to the invention of refrigerated methods of transportation was unreliable. The vaccine would be rendered impotent by heat and sunlight, and the method of drying samples on quills and shipping them to countries in need often resulted in an inactive vaccine. Another method employed was the "arm to arm" method. This involved vaccinating an individual then transferring it to another as soon as the infectious pustule forms, then to another, etc. This method was used as a form of living transportation of the vaccine, and usually employed orphans as carriers. However, this method was problematic due to the possibility of spreading other blood diseases, such as hepatitis and syphilis, as was the case in 1861, when 41 Italian children contracted syphilis after being vaccinated by the "arm to arm" method.^[26] Henry Austin Martin introduced a method for vaccine production from calves.^[27]

In 1913, E. Steinhardt, C. Israeli, and R. A. Lambert grew vaccinia virus in fragments of pig corneal tissue culture.^[28]

A paper published in 1915 by Fredrick W. Twort, a student of Willian Bulloch, is considered to be the beginning of modern phage research. He was attempting to grow vaccinia virus on agar media in the absence of living cells when he noted that many colonies of contaminating micrococci grew up and appeared mucoid, watery or glassy, and this transformation could be induced in other colonies by inoculation of the fresh colony with material from the watery colony. Using a microscope, he observed that bacteria had degenerated into small granules that stained red with Giemsa stain. He concluded that "...it [the agent of transformation] might almost be considered as an acute infectious disease of micrococci."^[29]

In 1939 Allan Watt Downie showed that the smallpox vaccines being used in the 20th century and cowpox virus were not the same, but were immunologically related.^[5][30]

2000–present

In March 2007, a 2-year-old Indiana boy and his mother contracted a life-threatening vaccinia infection from the boy's father.

In 2010, the Centers for Disease Control and Prevention (CDC) reported that a woman in Washington had contracted vaccinia virus infection after digital vaginal contact with her boyfriend, a military member who had recently been vaccinated for smallpox. The woman had a history of childhood eczema, but she had not been symptomatic as an adult. The CDC indicated that it was aware of four similar cases in the preceding 12 months of vaccinia infection after sexual contact with a recent military vaccinee.^[33] Further cases—also in patients with a history of eczema—occurred in 2012.^[34]

Common strains

This is a list of some of the well-characterized vaccinia strains used for research and vaccination.^{[citation needed]}

• Lister (also known as Elstree): the English vaccine strain used by Leslie Collier to develop heat stable vaccine in powdered form. Used as the basis for vaccine production during the World Health Organization Smallpox Eradication Campaign (SEC)
• freeze-dried
  and treated with antibiotics.
• EM63; Russian strain used in the SEC
• Vero cells
  .
• immunodeficient mice sick and therefore may be safer to use in humans who have weaker immune systems due to being very young, very old, having HIV/AIDS
  , etc.
• LC16m8: an attenuated strain developed and currently used in Japan
• CV-1: an attenuated strain developed in the United States and used there in the late 1960s- 1970s
• Western Reserve
• Copenhagen
• Connaught Laboratories (Canada)

• B13R (virus protein)

References