Vaccine description | |
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Target | Anthrax |
Anthrax vaccines are vaccines to prevent the livestock and human disease anthrax, caused by the bacterium Bacillus anthracis . [1]
They have had a prominent place in the history of medicine, from Pasteur's pioneering 19th-century work with cattle (the first effective bacterial vaccine and the second effective vaccine ever) to the controversial late 20th century use of a modern product to protect American troops against the use of anthrax in biological warfare. Human anthrax vaccines were developed by the Soviet Union in the late 1930s and in the US and UK in the 1950s. The current vaccine approved by the U.S. Food and Drug Administration (FDA) was formulated in the 1960s.
Currently administered human anthrax vaccines include acellular (USA, UK) and live spore (Russia) varieties. All currently used anthrax vaccines show considerable local and general reactogenicity (erythema, induration, soreness, fever) and serious adverse reactions occur in about 1% of recipients. [2] New third-generation vaccines being researched include recombinant live vaccines and recombinant sub-unit vaccines.
In the 1870s, the French chemist Louis Pasteur (1822–1895) applied his previous method of immunising chickens against chicken cholera to anthrax, which affected cattle, and thereby aroused widespread interest in combating other diseases with the same approach. In May 1881, Pasteur performed a famous public experiment at Pouilly-le-Fort to demonstrate his concept of vaccination. He prepared two groups of 25 sheep, one goat and several cows. The animals of one group were twice injected, with an interval of 15 days, with an anthrax vaccine prepared by Pasteur; a control group was left unvaccinated. Thirty days after the first injection, both groups were injected with a culture of live anthrax bacteria. All the animals in the non-vaccinated group died, while all of the animals in the vaccinated group survived. [3] The public reception was sensational.
Pasteur publicly claimed he had made the anthrax vaccine by exposing the bacilli to oxygen. His laboratory notebooks, now in the Bibliothèque Nationale in Paris, in fact show Pasteur used the method of rival Jean-Joseph-Henri Toussaint (1847–1890), a Toulouse veterinary surgeon, to create the anthrax vaccine. [4] [5] This method used the oxidizing agent potassium dichromate. Pasteur's oxygen method did eventually produce a vaccine but only after he had been awarded a patent on the production of an anthrax vaccine.
The notion of a weak form of a disease causing immunity to the virulent version was not new; this had been known for a long time for smallpox. Inoculation with smallpox (variolation) was known to result in far less scarring, and greatly reduced mortality, in comparison with the naturally acquired disease. The English physician Edward Jenner (1749–1823) had also discovered (1796) the process of vaccination by using cowpox to give cross-immunity to smallpox and by Pasteur's time this had generally replaced the use of actual smallpox material in inoculation. The difference between smallpox vaccination and anthrax or chicken cholera vaccination was that the weakened form of the latter two disease organisms had been "generated artificially", so a naturally weak form of the disease organism did not need to be found. This discovery revolutionized work in infectious diseases and Pasteur gave these artificially weakened diseases the generic name "vaccines", in honor of Jenner's groundbreaking discovery. In 1885, Pasteur produced his celebrated first vaccine for rabies by growing the virus in rabbits and then weakening it by drying the affected nerve tissue.
In 1995, the centennial of Pasteur's death, The New York Times ran an article titled "Pasteur's Deception". After having thoroughly read Pasteur's lab notes, the science historian Gerald L. Geison declared Pasteur had given a misleading account of the preparation of the anthrax vaccine used in the experiment at Pouilly-le-Fort. [6] [7] [8] The same year, Max Perutz published a vigorous defense of Pasteur in The New York Review of Books . [9] [10] [11]
The Austrian-South African immunologist Max Sterne (1905–1997) developed an attenuated live animal vaccine in 1935 that is still employed and derivatives of his strain account for almost all veterinary anthrax vaccines used in the world today. [12] Beginning in 1934 at the Onderstepoort Veterinary Research Institute, north of Pretoria, he prepared an attenuated anthrax vaccine, using the method developed by Pasteur. A persistent problem with Pasteur's vaccine was achieving the correct balance between virulence and immunogenicity during preparation. This notoriously difficult procedure regularly produced casualties among vaccinated animals. With little help from colleagues, Sterne performed small-scale experiments which isolated the "Sterne strain" (34F2) of anthrax which became, and remains today, the basis of most of the improved livestock anthrax vaccines throughout the world. [13] As Sterne's vaccine is a live vaccine, vaccination during use of antibiotics produces much reduced results and should be avoided. There is a withholding period after vaccination when animals cannot be slaughtered. No such period is defined for milk and there are no reports of humans being infected by products from vaccinated animals. There have been a few cases when humans accidentally self-inject the vaccine when trying to administer to a struggling animal. One case developed fever and meningitis, but it is unclear whether the illness was caused by the vaccine. Livestock anthrax vaccines are made in many countries around the world, most of which use 34F2 with saponin adjuvant. [14]
Anthrax vaccines were developed in the Soviet Union in the 1930s and available for use in humans by 1940. [15] [16] A live attenuated, unencapsulated spore vaccine became widely used for humans. It was given either by scarification or subcutaneous injection (only in emergency) [14] and its developers claimed that it was reasonably well tolerated and showed some degree of protective efficacy against cutaneous anthrax in clinical field trials. [16] The efficacy of the live Russian vaccine was reported to have been greater than that of either of the killed British or US anthrax vaccines (AVP and AVA, respectively) [17] [18] [19] [20] during the 1970s and '80s. The STI-1 vaccine, consisting only of freeze-dried spores, [14] is given in a two-dose schedule, but serious side-effects restricted its use to healthy adults. [21] It was reportedly manufactured at the George Eliava Institute of Bacteriophage, Microbiology and Virology in Tbilisi, Georgia, until 1991. [22] As of 2008, the STI-1 vaccine remains available, and is the only human anthrax vaccine "nominally available outside national borders". [14]
China uses a different live attenuated strain for their human vaccines, designated "A16R". The A16R vaccine is given as a suspention in 50% glycerol and distilled water. A single dose is given by scarification, followed by a booster in 6 or 12 months, then annual boosters. [14]
British biochemist Harry Smith (1921–2011), working for the UK bio-weapons program at Porton Down, discovered the three anthrax toxins in 1948. This discovery was the basis of the next generation of antigenic anthrax vaccines and for modern antitoxins to anthrax. [23] The widely used British anthrax vaccine—sometimes called Anthrax Vaccine Precipitated (AVP) to distinguish it from the similar AVA (see below)—became available for human use in 1954. This was a cell-free vaccine in distinction to the live-cell Pasteur-style vaccine previously used for veterinary purposes. [24] It is now manufactured by Porton Biopharma Ltd, a Company owned by the UK Department of Health.
AVP is administered at primovaccination in three doses with a booster dose after six months. The active ingredient is a sterile filtrate of an alum-precipitated anthrax antigen from the Sterne strain in a solution for injection. The other ingredients are aluminium potassium sulphate, sodium chloride and purified water. The preservative is thiomersal (0.005%). The vaccine is given by intramuscular injection and the primary course of four single injections (3 injections 3 weeks apart, followed by a 6-month dose) is followed by a single booster dose given once a year. During the Gulf War (1990–1991), UK military personnel were given AVP concomitantly with the pertussis vaccine as an adjuvant to improve overall immune response and efficacy.
The United States undertook basic research directed at producing a new anthrax vaccine during the 1950s and '60s. The product known as Anthrax Vaccine Adsorbed (AVA)—trade name BioThrax —was licensed in 1970 by the U.S. National Institutes of Health (NIH) and in 1972 the Food and Drug Administration (FDA) took over responsibility for vaccine licensure and oversight. AVA is produced from culture filtrates of an avirulent, nonencapsulated mutant of the B. anthracis Vollum strain known as V770-NP1-R. [25] No living organisms are present in the vaccine which results in protective immunity after 3 to 6 doses. [25] AVA remains the only FDA-licensed human anthrax vaccine in the United States and is produced by Emergent BioSolutions, formerly known as BioPort Corporation in Lansing, Michigan. The principal purchasers of the vaccine in the United States are the Department of Defense and Department of Health and Human Services. Ten million doses of AVA have been purchased for the U.S. Strategic National Stockpile for use in the event of a mass bioterrorist anthrax attack.
In 1997, the Clinton administration initiated the Anthrax Vaccine Immunization Program (AVIP), under which active U.S. service personnel were to be immunized with the vaccine. Controversy ensued since vaccination was mandatory and GAO published reports that questioned the safety and efficacy of AVA, causing sometimes serious side effects. [26] A Congressional report also questioned the safety and efficacy of the vaccine and challenged the legality of mandatory inoculations. [27] Mandatory vaccinations were halted in 2004 by a formal legal injunction which made numerous substantive challenges regarding the vaccine and its safety. [28] After reviewing extensive scientific evidence, the FDA determined in 2005 that AVA is safe and effective as licensed for the prevention of anthrax, regardless of the route of exposure. In 2006, the Defense Department announced the reinstatement of mandatory anthrax vaccinations for more than 200,000 troops and defense contractors. The vaccinations are required for most U.S. military units and civilian contractors assigned to homeland bioterrorism defense or deployed in Iraq, Afghanistan or South Korea. [29]
A number of experimental anthrax vaccines are undergoing pre-clinical testing, notably the Bacillus anthracis protective antigen—known as PA (see Anthrax toxin—combined with various adjuvants such as aluminum hydroxide (Alhydrogel), saponin QS-21, and monophosphoryl lipid A (MPL) in squalene/lecithin/Tween 80 emulsion (SLT). One dose of each formulation has provided significant protection (> 90%) against inhalational anthrax in rhesus macaques.
Bacillus Calmette–Guérin (BCG) vaccine is a vaccine primarily used against tuberculosis (TB). It is named after its inventors Albert Calmette and Camille Guérin. In countries where tuberculosis or leprosy is common, one dose is recommended in healthy babies as soon after birth as possible. In areas where tuberculosis is not common, only children at high risk are typically immunized, while suspected cases of tuberculosis are individually tested for and treated. Adults who do not have tuberculosis and have not been previously immunized, but are frequently exposed, may be immunized, as well. BCG also has some effectiveness against Buruli ulcer infection and other nontuberculous mycobacterial infections. Additionally, it is sometimes used as part of the treatment of bladder cancer.
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 body's adaptive immunity, they help prevent sickness from an infectious disease. When a sufficiently large percentage of a population has been vaccinated, herd immunity results. Herd immunity protects those who may be immunocompromised and cannot get a vaccine because even a weakened version would harm them. The effectiveness of vaccination has been widely studied and verified. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio and tetanus from much of the world. However, some diseases, such as measles outbreaks in America, have seen rising cases due to relatively low vaccination rates in the 2010s – attributed, in part, to vaccine hesitancy. According to the World Health Organization, vaccination prevents 3.5–5 million deaths per year.
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and recognize further and destroy any of the microorganisms associated with that agent that it may encounter in the future.
Anthrax is an infection caused by the bacterium Bacillus anthracis. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one day and more than two months after the infection is contracted. The skin form presents with a small blister with surrounding swelling that often turns into a painless ulcer with a black center. The inhalation form presents with fever, chest pain and shortness of breath. The intestinal form presents with diarrhea, abdominal pains, nausea and vomiting.
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.
Immunization, or immunisation, is the process by which an individual's immune system becomes fortified against an infectious agent.
In biology, immunity is the state of being insusceptible or resistant to a noxious agent or process, especially a pathogen or infectious disease. Immunity may occur naturally or be produced by prior exposure or immunization.
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.
Vaccine hesitancy is a delay in acceptance, or refusal, of vaccines despite the availability of vaccine services and supporting evidence. The term covers refusals to vaccinate, delaying vaccines, accepting vaccines but remaining uncertain about their use, or using certain vaccines but not others. The scientific consensus that vaccines are generally safe and effective is overwhelming. Vaccine hesitancy often results in disease outbreaks and deaths from vaccine-preventable diseases. Therefore, the World Health Organization characterizes vaccine hesitancy as one of the top ten global health threats.
The Ames strain is one of 89 known strains of the anthrax bacterium. It was isolated from a diseased 14-month-old Beefmaster heifer that died in Sarita, Texas in 1981. The strain was isolated at the Texas Veterinary Medical Diagnostic Laboratory and a sample was sent to the United States Army Medical Research Institute of Infectious Diseases (USAMRIID). Researchers at USAMRIID mistakenly believed the strain came from Ames, Iowa because the return address on the package was the USDA's National Veterinary Services Laboratories in Ames and mislabeled the specimen.
Artificial induction of immunity is immunization achieved by human efforts in preventive healthcare, as opposed to natural immunity as produced by organisms' immune systems. It makes people immune to specific diseases by means other than waiting for them to catch the disease. The purpose is to reduce the risk of death and suffering, that is, the disease burden, even when eradication of the disease is not possible. Vaccination is the chief type of such immunization, greatly reducing the burden of vaccine-preventable diseases.
Tuberculosis (TB) vaccines are vaccinations intended for the prevention of tuberculosis. Immunotherapy as a defence against TB was first proposed in 1890 by Robert Koch. Today, the only effective tuberculosis vaccine in common use is the Bacillus Calmette-Guérin (BCG) vaccine, first used on humans in 1921. It consists of attenuated (weakened) strains of the cattle tuberculosis bacillus. It is recommended for babies in countries where tuberculosis is common.
Mumps vaccines are vaccines which prevent mumps. When given to a majority of the population they decrease complications at the population level. Effectiveness when 90% of a population is vaccinated is estimated at 85%. Two doses are required for long term prevention. The initial dose is recommended between 12 and 18 months of age. The second dose is then typically given between two years and six years of age. Usage after exposure in those not already immune may be useful.
The Anthrax Vaccine Immunization Program (AVIP), is the name of the policy set forth by the U.S. federal government to immunize its military and certain civilian personnel with BioThrax, an anthrax vaccine manufactured by Emergent BioSolutions Inc. It was set up by the Clinton administration.
An attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable. Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by "killing" the pathogen.
The rabies vaccine is a vaccine used to prevent rabies. There are several rabies vaccines available that are both safe and effective. Vaccinations must be administered prior to rabies virus exposure or within the latent period after exposure to prevent the disease. Transmission of rabies virus to humans typically occurs through a bite or scratch from an infectious animal, but exposure can occur through indirect contact with the saliva from an infectious individual.
Bacillus anthracis is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent (obligate) pathogen within the genus Bacillus. Its infection is a type of zoonosis, as it is transmitted from animals to humans. It was discovered by a German physician Robert Koch in 1876, and became the first bacterium to be experimentally shown as a pathogen. The discovery was also the first scientific evidence for the germ theory of diseases.
Tick-borne encephalitis vaccine is a vaccine used to prevent tick-borne encephalitis (TBE). The disease is most common in Central and Eastern Europe, and Northern Asia. More than 87% of people who receive the vaccine develop immunity. It is not useful following the bite of an infected tick. It is given by injection into a muscle.
Yellow fever vaccine is a vaccine that protects against yellow fever. Yellow fever is a viral infection that occurs in Africa and South America. Most people begin to develop immunity within ten days of vaccination and 99% are protected within one month, and this appears to be lifelong. The vaccine can be used to control outbreaks of disease. It is given either by injection into a muscle or just under the skin.
Anthrax vaccine adsorbed, sold under the brand name Biothrax among others, is a vaccine intended to provide acquired immunity against Bacillus anthracis.
Fortunately, Pasteur's colleagues Chamberlain [ sic ] and Roux followed up the results of a research physician Jean-Joseph-Henri Toussaint, who had reported a year earlier that carbolic-acid/heated anthrax serum would immunize against anthrax. These results were difficult to reproduce and discarded although, as it turned out, Toussaint had been on the right track. This led Pasteur and his assistants to substitute an anthrax vaccine prepared by a method similar to that of Toussaint and different from what Pasteur had announced.