''Vaccinia virus'' (VACV or VV) is a large, complex,
enveloped virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
belonging to the
poxvirus
''Poxviridae'' is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated wit ...
family.
It has a linear, double-stranded
DNA genome
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...
approximately 190
kbp in length, which encodes approximately 250
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
s. The dimensions of the
virion
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
are roughly 360 × 270 × 250
nm, with a mass of approximately 5–10
fg. The vaccinia virus is the source of the modern
smallpox vaccine
The smallpox vaccine is the first vaccine to be developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox ...
, which the World Health Organisation used to eradicate smallpox in a global vaccination campaign in 1958–1977. Although ''smallpox'' no longer exists in the wild, ''vaccinia'' virus is still studied widely by scientists as a tool for
gene therapy
Gene therapy is a medical field which focuses on the genetic modification of cells to produce a therapeutic effect or the treatment of disease by repairing or reconstructing defective genetic material. The first attempt at modifying human DN ...
and
genetic engineering
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...
.
Smallpox
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ...
had been an endemic human disease that had a 30% fatality rate. In 1796, the British doctor
Edward Jenner
Edward Jenner, (17 May 1749 – 26 January 1823) was a British physician and scientist who pioneered the concept of vaccines, and created the smallpox vaccine, the world's first vaccine. The terms ''vaccine'' and ''vaccination'' are derived f ...
proved that an infection with the relatively mild
cowpox
Cowpox is an infectious disease caused by the ''cowpox virus'' (CPXV). It presents with large blisters in the skin, a fever and swollen glands, historically typically following contact with an infected cow, though in the last several decades more ...
virus would also confer immunity to the deadly smallpox. Jenner referred to cowpox as ''variolae vaccinae'' (smallpox of the cow). However, the origins of the smallpox vaccine became murky over time, especially after
Louis Pasteur
Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization, the latter of which was named afte ...
developed laboratory techniques for creating vaccines in the 19th century.
Allan Watt Downie
Allan Watt Downie FRS (5 September 1901 – 26 January 1988) was a Scottish microbiologist involved in the eradication of smallpox. He was elected a Fellow of the Royal Society
Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is ...
demonstrated in 1939 that the modern smallpox vaccine was serologically distinct from cowpox,
and ''vaccinia'' was subsequently recognized as a separate viral species. Whole-genome sequencing has revealed that ''vaccinia'' is most closely related to
horsepox
''Orthopoxvirus'' is a genus of viruses in the family ''Poxviridae'' and subfamily ''Chordopoxvirinae''. Vertebrates, including mammals and humans, and arthropods serve as natural hosts. There are 12 species in this genus. Diseases associated wi ...
, and the cowpox strains found in Great Britain are the ''least'' closely related to ''vaccinia''.
Classification of vaccinia infections
In addition to the morbidity of uncomplicated primary vaccination, transfer of infection to other sites by scratching, and post-vaccinial
encephalitis
Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...
, other complications of vaccinia infections may be divided into the following types:
*
Generalized vaccinia
Generalized vaccinia is a cutaneous condition that occurs 6–9 days after vaccination, characterized by a generalized eruption of skin lesions, and caused by the vaccinia virus.
See also
* Vaccinia
* Skin lesion
A skin condition, also known ...
*
Eczema vaccinatum
Eczema vaccinatum is a rare severe adverse reaction to smallpox vaccination.
It is characterized by serious local or disseminated, umbilicated, vesicular, crusting skin rashes in the face, neck, chest, abdomen, upper limbs and hands, caused by wid ...
*
Progressive vaccinia
Progressive vaccinia is a rare cutaneous condition caused by the vaccinia virus, characterized by painless but progressive necrosis and ulceration. Presentation Complications
Opportunistic fungal, protozoal, or bacterial infections and the vaccin ...
(vaccinia gangrenosum, vaccinia necrosum)
*
Roseola vaccinia
Roseola vaccinia is a cutaneous condition characterized by a prominent rim of erythema surrounding the site of vaccinia injection.
See also
* Vaccinia
* Skin lesion
A skin condition, also known as cutaneous condition, is any medical conditio ...
Origin
Vaccinia virus is closely related to the virus that causes
cowpox
Cowpox is an infectious disease caused by the ''cowpox virus'' (CPXV). It presents with large blisters in the skin, a fever and swollen glands, historically typically following contact with an infected cow, though in the last several decades more ...
; historically the two were often considered to be one and the same.
The precise origin of vaccinia virus is unknown due to the lack of record-keeping, as the virus was repeatedly cultivated and
passaged in research laboratories for many decades.
The most common notion is that vaccinia virus, cowpox virus, and
variola
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) cer ...
virus (the causative agent of smallpox) were all derived from a common ancestral virus. There is also speculation that vaccinia virus was originally isolated from
horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million y ...
s,
and analysis of DNA from an early (1902) sample of smallpox vaccine showed that it was 99.7% similar to horsepox virus.
Virology
Poxviruses are unique among
DNA virus
A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. They can be divided between those that have two strands of DNA in their genome, called double-stranded DNA (dsDNA) viruses, and ...
es because they
replicate only in the
cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...
of the
host cell
In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include a ...
, outside of the
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucle ...
. Therefore, the large genome is required for encoding various
enzymes
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
and proteins involved in viral DNA replication and gene
transcription
Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including:
Genetics
* Transcription (biology), the copying of DNA into RNA, the fir ...
. During its replication cycle, VV produces four infectious forms which differ in their outer
membranes
A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...
: intracellular mature virion (IMV), the intracellular enveloped virion (IEV), the cell-associated enveloped virion (CEV) and the extracellular enveloped virion (EEV). Although the issue remains contentious, the prevailing view is that the IMV consists of a single
lipoprotein
A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, sur ...
membrane, while the CEV and EEV are both surrounded by two membrane layers and the IEV has three envelopes. The IMV is the most abundant infectious form and is thought to be responsible for spread between hosts. On the other hand, the CEV is believed to play a role in cell-to-cell spread and the EEV is thought to be important for long range dissemination within the host organism.
Multiplicity reactivation
Vaccinia virus is able to undergo multiplicity reactivation (MR).
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
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, nitrogen mustard, and X-rays or gamma rays. Michod et al. 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.
Host resistance
Vaccinia contains within its genome genes for several
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s that give the virus resistance to
interferon
Interferons (IFNs, ) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten the ...
s:
* K3L () is a protein with
homology
Homology may refer to:
Sciences
Biology
*Homology (biology), any characteristic of biological organisms that is derived from a common ancestor
* Sequence homology, biological homology between DNA, RNA, or protein sequences
*Homologous chrom ...
to the protein ''
eukaryotic initiation factor 2'' (eIF-2alpha). K3L protein inhibits the action of
PKR, an activator of interferons.
[
* E3L () is another protein encoded by Vaccinia. E3L also inhibits PKR activation; and is also able to bind to double stranded RNA.]
* B18R is a protein which serves as an interferon
Interferons (IFNs, ) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten the ...
inhibitor in one of Moderna
Moderna, Inc. ( ) is an American pharmaceutical and biotechnology company based in Cambridge, Massachusetts that focuses on RNA therapeutics, primarily mRNA vaccines. These vaccines use a copy of a molecule called messenger RNA (mRNA) to produ ...
's technologies.
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 fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
. Immune responses generated from a vaccinia virus infection protects the person against a lethal smallpox
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ...
infection. For this reason, vaccinia virus was, and still is, being used as a live-virus vaccine against smallpox. Unlike vaccines that use weakened forms of the virus being vaccinated against, the vaccinia virus vaccine cannot cause a smallpox infection because it does not contain the smallpox virus. However, certain complications and/or vaccine adverse effects occasionally arise. The chance of this happening is significantly increased in people who are immunocompromised
Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...
. Approximately 1 to 2 people out of every 1 million people vaccinated could die as a result of life-threatening reactions to the vaccination
Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating ...
. The rate of myopericarditis with ACAM2000 is 5.7 per 1,000 of primary vaccinees.
On September 1, 2007, the U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
(FDA) licensed a new vaccine
A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifie ...
ACAM2000
ACAM2000 is a smallpox vaccine manufactured by Sanofi Pasteur Biologics Co. The vaccine provides protection against smallpox for people determined to be at high risk for smallpox infection.
Background
Smallpox is considered a biological threa ...
against smallpox
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ...
which can be produced quickly upon need. Manufactured by Sanofi Pasteur
Sanofi Pasteur is the vaccines division of the French multinational pharmaceutical company Sanofi. Sanofi Pasteur is the largest company in the world devoted entirely to vaccines. It is one of four global producers of the yellow fever vaccine.
...
, the U.S. Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
stockpiled 192.5 million doses of the new vaccine (see list of common strains below).
A smallpox vaccine, Imvanex
The smallpox vaccine is the first vaccine to be developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox ...
, which is based on the Modified vaccinia Ankara
Modified vaccinia Ankara (MVA) is an attenuated (weakened) strain of the vaccinia virus. It is being used as a vaccine (called MVA-BN, brand names: Imvanex in the EU, Imvamune in Canada, and Jynneos in the US) against smallpox and monkeypox, havi ...
strain, was approved by the European Medicines Agency in 2013. This strain has been used in vaccines during the 2022 monkeypox outbreak.
''Vaccinia'' is also used in recombinant vaccines
A vaccine is a biological preparation that provides active acquired immunity
The adaptive immune system, also known as the acquired immune system, is a subsystem of the immune system that is composed of specialized, systemic cells and pro ...
, as a vector for expression of foreign genes within a host, in order to generate an immune response. Other poxviruses
''Poxviridae'' is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated wit ...
are also used as live recombinant vaccines.
History
The original vaccine for smallpox, and the origin of the idea of vaccination, was Cowpox
Cowpox is an infectious disease caused by the ''cowpox virus'' (CPXV). It presents with large blisters in the skin, a fever and swollen glands, historically typically following contact with an infected cow, though in the last several decades more ...
, described by Edward Jenner
Edward Jenner, (17 May 1749 – 26 January 1823) was a British physician and scientist who pioneered the concept of vaccines, and created the smallpox vaccine, the world's first vaccine. The terms ''vaccine'' and ''vaccination'' are derived f ...
in 1798. The Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
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. 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. Henry Austin Martin introduced a method for vaccine production from calves.
In 1913, E. Steinhardt, C. Israeli, and R. A. Lambert grew vaccinia virus in fragments of pig cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power ...
l tissue culture
Tissue culture is the growth of tissues or cells in an artificial medium separate from the parent organism. This technique is also called micropropagation. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, su ...
.
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
Giemsa stain (), named after German chemist and bacteriologist Gustav Giemsa, is a nucleic acid stain used in cytogenetics and for the histopathological diagnosis of malaria and other parasites.
Uses
It is specific for the phosphate groups of ...
. He concluded that "...it he agent of transformationmight almost be considered as an acute infectious disease of micrococci."
In 1939 Allan Watt Downie
Allan Watt Downie FRS (5 September 1901 – 26 January 1988) was a Scottish microbiologist involved in the eradication of smallpox. He was elected a Fellow of the Royal Society
Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is ...
showed that the smallpox vaccines being used in the 20th century and cowpox virus were not the same, but were immunologically related.
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. The boy developed the telltale rash over 80 percent of his body after coming into close contact with his father, who was vaccinated for smallpox before being deployed overseas by the United States Army
The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...
. The United States military resumed smallpox vaccinations in 2002. The child acquired the infection due to eczema
Dermatitis is inflammation of the Human skin, skin, typically characterized by itchiness, erythema, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become lichenification, thick ...
, which is a known risk factor for vaccinia infection. The boy was treated with intravenous immunoglobulin
Immunoglobulin therapy is the use of a mixture of antibodies (normal human immunoglobulin or NHIG) to treat several health conditions. These conditions include primary immunodeficiency, immune thrombocytopenic purpura, chronic inflammatory dem ...
, cidofovir
Cidofovir, brand name Vistide, is a topical or injectable antiviral medication primarily used as a treatment for cytomegalovirus (CMV) retinitis (an infection of the retina of the eye) in people with AIDS.
Cidofovir was approved for medical us ...
, and Tecovirimat
Tecovirimat, sold under the brand name Tpoxx among others, is an antiviral medication with activity against orthopoxviruses such as smallpox and monkeypox. It is the first antipoxviral drug approved in the United States. It is an inhibitor of th ...
(ST-246), a (then) experimental drug developed by SIGA Technologies
SIGA Technologies, Inc. is an American pharmaceutical company founded in 1995, currently based in New York City, which develops and sells pharmaceutical solutions for the antiviral treatment of smallpox, monkeypox, cowpox, and vaccinia complicatio ...
. On April 19, 2007, he was sent home with no after effects except for possible scarring of the skin.[
In 2010, the ]Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
(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. Further cases—also in patients with a history of eczema—occurred in 2012.
Common strains
This is a list of some of the well-characterized vaccinia strains used for research and vaccination.
* Lister (also known as Elstree): the English vaccine strain used by Leslie Collier
Leslie Harold Collier (9 February 1921 – 14 March 2011) was a scientist responsible for developing a freeze-drying method to produce a more heat stable smallpox vaccine in the late 1940s. Collier added a key component, Peptide#Classes, pepton ...
to develop heat stable vaccine in powdered form. Used as the basis for vaccine production during the World Health Organization Smallpox Eradication Campaign (SEC)
* Dryvax
The smallpox vaccine is the first vaccine to be developed against a contagious disease. In 1796, British physician Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox ...
(also known as "Wyeth"): the vaccine strain previously used in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, produced by Wyeth
Wyeth, LLC was an American pharmaceutical company. The company was founded in Philadelphia, Pennsylvania, in 1860 as ''John Wyeth and Brother''. It was later known, in the early 1930s, as American Home Products, before being renamed to Wyeth in ...
. Used in the SEC, it was replaced in 2008 by ACAM2000 (see below), produced by Acambis. It was produced as preparations of calf
Calf most often refers to:
* Calf (animal), the young of domestic cattle.
* Calf (leg), in humans (and other primates), the back portion of the lower leg
Calf or calves may also refer to:
Biology and animal byproducts
* Veal, meat from calves
* ...
lymph
Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to ...
which was freeze-dried
Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process that involves freezing the product and lowering pressure, removing the ice by sublimation. This is in contrast to dehydration by most conve ...
and treated with antibiotics.
* EM63; Russian strain used in the SEC
* ACAM2000
ACAM2000 is a smallpox vaccine manufactured by Sanofi Pasteur Biologics Co. The vaccine provides protection against smallpox for people determined to be at high risk for smallpox infection.
Background
Smallpox is considered a biological threa ...
: The current strain in use in the US, produced by Acambis. ACAM2000 was derived from a clone of a Dryvax virus by plaque purification. It is produced in cultures of Vero cells
Vero may refer to: Geography
* Vero Beach, Florida, a city in the United States
* Vero, Corse-du-Sud, a commune of France in Corsica Other
* ''Véro'', a talk show on the Radio-Canada television network
* Vero (app), a social media company co-found ...
.
* Modified vaccinia Ankara
Modified vaccinia Ankara (MVA) is an attenuated (weakened) strain of the vaccinia virus. It is being used as a vaccine (called MVA-BN, brand names: Imvanex in the EU, Imvamune in Canada, and Jynneos in the US) against smallpox and monkeypox, havi ...
(also known as MVA): a highly attenuated (not virulent) strain created by passaging vaccinia virus several hundred times in chicken
The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adult m ...
embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
fibroblasts
A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells o ...
. Unlike some other vaccinia strains it does not make immunodeficient
Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...
mice
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
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
Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...
, 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)
References
Further reading
*
*
*
*
*
*
*
External links
Virus Pathogen Database and Analysis Resource (ViPR): Poxviridae
{{Taxonbar, from=Q1986297
Chordopoxvirinae
Virus-related cutaneous conditions
Genetic engineering