Vaccine description | |
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Target | Smallpox, mpox |
Vaccine type | Attenuated |
Clinical data | |
Trade names | Imvanex, Imvamune, Jynneos |
Other names | MVA |
AHFS/Drugs.com | Professional Drug Facts |
Routes of administration | Subcutaneous, Intradermal [1] |
ATC code | |
Legal status | |
Legal status | |
Identifiers | |
ChemSpider |
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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, [3] Imvamune in Canada, [2] and Jynneos in the US [1] ) against smallpox and mpox, [4] having fewer side effects than smallpox vaccines derived from other poxviruses. [5]
This third-generation smallpox vaccine has the advantage that it cannot reproduce complete virions in human cells, "the block of the MVA life cycle occurs at the step of virion assembly resulting in assembly of immature virus particles that are not released from the infected cell." [5]
By inserting antigen genes into its genome, modified vaccinia Ankara virus is also used as an experimental viral vector for vaccines against non-poxvirus diseases. [6]
The traditional smallpox vaccine, which was used in the smallpox eradication campaign 1958–1977, consists of a live vaccinia virus which can replicate in humans but usually does not cause disease. It can however sometimes lead to serious side effects. Modified vaccinia Ankara virus is a highly attenuated strain of vaccinia virus that was developed in Munich, Germany between 1953 and 1968. It was produced by more than 500 serial passages of vaccinia virus (from a wild strain discovered by the Turkish vaccine institute of Ankara) in chicken embryo fibroblasts. [5] After testing the safety and effectiveness as a vaccine, it was approved in Germany in 1977, and then given to about 120,000 people until 1980, when smallpox vaccinations ended in Germany. No severe adverse events were seen during this time. [5]
It was later found that through the passaging, modified vaccinia virus Ankara had lost about 10% of the ancestral vaccinia genome and with it the ability to replicate efficiently in most mammalian cells. While it can enter host cells, express its genes and replicate its genome, it fails to assemble virus particles that are released from the cell. [5]
The vaccine was further developed and manufactured by the Danish company Bavarian Nordic, resulting in the vaccine MVA-BN, which is unable to replicate in human cells. [7] The vaccine is given subcutaneously in two doses, at least 28 days apart. [8] It was approved in Canada in 2013, as a smallpox vaccine [9] and in 2020 also against mpox and related orthopoxvirus infections. It was approved in the European Union in 2013, as a vaccine against smallpox [3] [8] and in the US in September 2019, against smallpox and mpox. [10] [11] [12]
In August 2022, the US Food and Drug Administration (FDA) gave emergency use authorization for intradermal (rather than subcutaneous) mpox vaccination using a lower dose of Jynneos, which would increase the number of available doses up to five-fold. The vaccination would still be given in two doses, 28 days apart. A 2015 study had tested a regimen of one-fifth dose given intradermally. [13]
Modified vaccinia Ankara strains engineered to express foreign genes are vectors for production of recombinant proteins, the most common being a vaccine delivery system for antigens. [6] A recombinant MVA-based vector for vaccination with different fluorescent reporter genes was developed, which indicate the progress of genetic recombination with the transgene of an antigen (green, colorless, red). [14] [15]
In animal models, MVA-based vector vaccines have been found to be immunogenic and protective against various infectious agents including immunodeficiency viruses, influenza, [15] parainfluenza, measles virus, flaviviruses, tuberculosis, [16] Plasmodium parasites as well as certain cancers. [17]
MVA-B is an experimental vaccine to protect against HIV infection, produced by inserting HIV genes into the genome of modified vaccinia virus Ankara. In phase I clinical trials in 2013, it was found to be safe but produced only moderate levels of anti-HIV immunity. [18] After removing a certain MVA gene, the vaccine produced an improved immune response in mice. [19]
A US Centers for Disease Control and Prevention (CDC) analysis of the vaccination status of 5402 individuals who had mpox infections during the summer of 2022 showed that unvaccinated people appeared to be 14 times more likely to be infected than those with a single (of two recommended) doses; the results were noted to be admittedly preliminary. [20]
A DNA vaccine is a type of vaccine that transfects a specific antigen-coding DNA sequence into the cells of an organism as a mechanism to induce an immune response.
The smallpox vaccine is the first vaccine to have been 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 virus. Cowpox served as a natural vaccine until the modern smallpox vaccine emerged in the 20th century. From 1958 to 1977, the World Health Organization (WHO) conducted a global vaccination campaign that eradicated smallpox, making it the only human disease to be eradicated. Although routine smallpox vaccination is no longer performed on the general public, the vaccine is still being produced to guard against bioterrorism, biological warfare, and mpox.
Mpox is an infectious viral disease that can occur in humans and some other animals. Symptoms include a rash that forms blisters and then crusts over, fever, and swollen lymph nodes. The illness is usually mild and most of those infected will recover within a few weeks without treatment. The time from exposure to onset of symptoms ranges from five to twenty-one days and symptoms typically last from two to four weeks. Cases may be severe, especially in children, pregnant women or people with suppressed immune systems.
Vaccinia virus is a large, complex, enveloped virus belonging to the poxvirus family. It has a linear, double-stranded DNA genome approximately 190 kbp in length, which encodes approximately 250 genes. The dimensions of the virion 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, which the World Health Organization (WHO) 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 and genetic engineering.
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 with this genus include smallpox, cowpox, horsepox, camelpox, and monkeypox. The most widely known member of the genus is Variola virus, which causes smallpox. It was eradicated globally by 1977, through the use of Vaccinia virus as a vaccine. The most recently described species is the Alaskapox virus, first isolated in 2015.
TroVax is a cancer vaccine that was developed by Oxford BioMedica. No cancer vaccines have been proven to cure cancer or extend life yet, TroVax has been studied in a number of trials for colon cancer.
GeoVax is a clinical-stage biotechnology company which develops vaccines. GeoVax's development platform uses Modified Vaccinia Ankara (MVA) vector technology, with improvements to antigen design and manufacturing capabilities. GeoVax uses recombinant DNA or recombinant viruses to produce virus-like particles (VLPs) in the person being vaccinated.
MVA-B, or Modified Vaccinia Ankara B, is an HIV vaccine created to give immune resistance to infection by the human immunodeficiency virus. It was developed by a team of Spanish researchers at the Spanish National Research Council's Biotechnology National Centre headed by Dr. Mariano Esteban. The vaccine is based on the Modified vaccinia Ankara (MVA) virus used during the 1970s to help eradicate the smallpox virus. The B in the name "refers to HIV-B, the most common HIV subtype in Europe". It has been stated by Dr. Esteban that, in the future, the vaccine could potentially reduce the virulence of HIV to a "minor chronic infection akin to herpes".
The monkeypox virus, is a species of double-stranded DNA virus that causes mpox disease in humans and other mammals. The monkeypox virus is a zoonotic virus belonging to the orthopoxvirus genus, making it closely related to the variola, cowpox, and vaccinia viruses. MPV is oval-shaped with a lipoprotein outer membrane. The genome is approximately 190 kb.
Vaccinia immune globulin (VIG) is made from the pooled blood of individuals who have been inoculated with the smallpox vaccine. The antibodies these individuals developed in response to the smallpox vaccine are removed and purified. This results in VIG. It can be administered intravenously. It is used to treat individuals who have developed progressive vaccinia after smallpox vaccination.
Bavarian Nordic A/S is a fully integrated biotechnology company focused on the development, manufacturing and commercialization of vaccines for infectious diseases and cancer immunotherapies. The company is headquartered in Hellerup, Denmark, with a manufacturing facility in Kvistgård, and an additional site in Hørsholm. The company has a research and development facility in Martinsried, Germany, and offices in Zug, Switzerland, and Morrisville, North Carolina. The company uses viral vectors in its research and development.
Ebola vaccines are vaccines either approved or in development to prevent Ebola. As of 2022, there are only vaccines against the Zaire ebolavirus. The first vaccine to be approved in the United States was rVSV-ZEBOV in December 2019. It had been used extensively in the Kivu Ebola epidemic under a compassionate use protocol. During the early 21st century, several vaccine candidates displayed efficacy to protect nonhuman primates against lethal infection.
Antonio G. Siccardi is an Italian immunologist and virologist.
Raccoonpox virus (RCN) is a double-stranded DNA virus and a member of the orthopoxviruses in the family Poxviridae and subfamily Chordopoxvirinae which consists of eight genera: Avipoxvirus, Capripoxvirus, Leporipoxvirus, Molluscipoxvirus, Orthopoxvirus, Parapoxvirus, Suipoxvirus and Yatapoxvirus Vertebrates are the natural host of Chordopoxvirinae subfamily viruses. More specifically, raccoons are the natural hosts of RCN. RCN was isolated in 1961 from the upper respiratory tissues of 2 raccoons in a group of 92 observably healthy raccoons trapped close to Aberdeen, Maryland.
ChAdOx1 is an adenoviral vector for vaccines that was developed by the Jenner Institute, University of Oxford. The vector is a chimpanzee adenovirus modified to avoid its replication.
A viral vector vaccine is a vaccine that uses a viral vector to deliver genetic material (DNA) that can be transcribed by the recipient's host cells as mRNA coding for a desired protein, or antigen, to elicit an immune response. As of April 2021, six viral vector vaccines, four COVID-19 vaccines and two Ebola vaccines, have been authorized for use in humans.
A genetic vaccine is a vaccine that contains nucleic acids such as DNA or RNA that lead to protein biosynthesis of antigens within a cell. Genetic vaccines thus include DNA vaccines, RNA vaccines and viral vector vaccines.
The 2022–2023 mpox outbreak in the United States is part of the larger outbreak of human mpox caused by the West African clade of the monkeypox virus. The United States was the fourth country outside of the African countries with endemic mpox, to experience an outbreak in 2022. The first case was documented in Boston, Massachusetts, on May 17, 2022. As of August 22, mpox has spread to all 50 states in the United States, as well as Washington, D.C., and Puerto Rico. The United States has the highest number of mpox cases in the world. California has the highest number of mpox cases in the United States.
Polyvalent influenza vaccine is a type of influenza vaccine that provides immunity against more than one type of antigen. In the second week after receiving the flu shot, the body's immune system is triggered by the antigens so the body starts producing antibodies. These antibodies help fight against influenza viruses. Influenza symptoms and deaths can be prevented by getting an influenza vaccine every year. Currently circulating influenza strains that can cause seasonal epidemics include influenza A viruses, which can be further divided into subtype A(H1N1) and A(H3N2), and influenza B viruses.
Harriet Latham Robinson is an American vaccine researcher who is founder and Chief Scientific Officer Emeritus at GeoVax. She is the former Chief of Microbiology and Immunology at the Yerkes National Primate Research Center and Asa Griggs Candler Professor of Microbiology at Emory University. Her research considered HIV vaccine development. She is a Fellow of the American Association for the Advancement of Science.