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71-434: Adjuvants increase the body's immune response to a vaccine by creating higher levels of antibodies . They can either enhance, modulate, and/or prolong the body's immune response, reducing the number of vaccinations needed for immunization. The Matrix-M adjuvant is used in a number of vaccine candidates, including the malaria vaccine R21/Matrix-M, influenza vaccines , and in the approved Novavax COVID-19 vaccine . In 2021,

142-456: A 10–11-year study of 657,461 children found that the MMR vaccine does not cause autism and actually reduced the risk of autism by seven percent. Beside the active vaccine itself, the following excipients and residual manufacturing compounds are present or may be present in vaccine preparations: Various fairly standardized abbreviations for vaccine names have developed, although the standardization

213-435: A broad immune response. Although most attenuated vaccines are viral, some are bacterial in nature. Examples include the viral diseases yellow fever , measles , mumps , and rubella , and the bacterial disease typhoid . The live Mycobacterium tuberculosis vaccine developed by Calmette and Guérin is not made of a contagious strain but contains a virulently modified strain called " BCG " used to elicit an immune response to

284-550: A complete clinical cycle of development and trials proves the vaccine is safe and has long-term effectiveness, following scientific review by a multinational or national regulatory organization, such as the European Medicines Agency (EMA) or the US Food and Drug Administration (FDA). Upon developing countries adopting WHO guidelines for vaccine development and licensure, each country has its own responsibility to issue

355-468: A faulty B or T cell can begin exterminating the host's own healthy cells. Activation of naïve helper T cells occurs when antigen-presenting cells (APCs) present foreign antigen via MHC class II molecules on their cell surface. These APCs include dendritic cells , B cells , and macrophages which are specially equipped not only with MHC class II but also with co-stimulatory ligands which are recognized by co-stimulatory receptors on helper T cells. Without

426-415: A given immune reaction. In some cases vaccines may result in partial immune protection (in which immunity is less than 100% effective but still reduces risk of infection) or in temporary immune protection (in which immunity wanes over time) rather than full or permanent immunity. They can still raise the reinfection threshold for the population as a whole and make a substantial impact. They can also mitigate

497-507: A national licensure, and to manage, deploy, and monitor the vaccine throughout its use in each nation. Building trust and acceptance of a licensed vaccine among the public is a task of communication by governments and healthcare personnel to ensure a vaccination campaign proceeds smoothly, saves lives, and enables economic recovery. When a vaccine is licensed, it will initially be in limited supply due to variable manufacturing, distribution, and logistical factors, requiring an allocation plan for

568-400: A strong immune response. When two or more vaccines are mixed in the same formulation, the two vaccines can interfere. This most frequently occurs with live attenuated vaccines, where one of the vaccine components is more robust than the others and suppresses the growth and immune response to the other components. This phenomenon was first noted in the trivalent Sabin polio vaccine , where

639-422: A very important component for a strong response against an invader. The first contact that an organism has with a particular antigen will result in the production of effector T and B cells which are activated cells that defend against the pathogen. The production of these effector cells as a result of the first-time exposure is called a primary immune response. Memory T and memory B cells are also produced in

710-441: Is antitumor immunity . In general, there are two branches of the immune response, the innate and the adaptive , which work together to protect against pathogens. Both branches engage humoral and cellular components. The innate branch—the body's first reaction to an invader—is known to be a non-specific and quick response to any sort of pathogen . Components of the innate immune response include physical barriers like

781-525: Is a stub . You can help Misplaced Pages by expanding it . This article about medicinal chemistry is a stub . You can help Misplaced Pages by expanding it . Immune response An immune response is a physiological reaction which occurs within an organism in the context of inflammation for the purpose of defending against exogenous factors. These include a wide variety of different toxins , viruses , intra- and extracellular bacteria , protozoa , helminths , and fungi which could cause serious problems to

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852-420: 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

923-537: Is a novel type of vaccine which is composed of the nucleic acid RNA, packaged within a vector such as lipid nanoparticles . Among the COVID-19 vaccines are a number of RNA vaccines to combat the COVID-19 pandemic and some have been approved or have received emergency use authorization in some countries. For example, the Pfizer-BioNTech vaccine and Moderna mRNA vaccine are approved for use in adults and children in

994-416: Is activated by foreign surfaces such as viruses, fungi, bacteria, parasites, etc., and is capable of autoactivation due to “tickover” of C3. The lectin pathway is triggered when mannose-binding lectin (MBL) or ficolin aka specific pattern recognition receptors bind to pathogen-associated molecular patterns on the surface of invading microorganisms such as yeast , bacteria, parasites, and viruses. Each of

1065-516: Is at the CDC's page called "Vaccine Acronyms and Abbreviations", with abbreviations used on U.S. immunization records. The United States Adopted Name system has some conventions for the word order of vaccine names, placing head nouns first and adjectives postpositively . This is why the USAN for " OPV " is "poliovirus vaccine live oral" rather than "oral poliovirus vaccine". A vaccine licensure occurs after

1136-494: Is by no means centralized or global. For example, the vaccine names used in the United States have well-established abbreviations that are also widely known and used elsewhere. An extensive list of them provided in a sortable table and freely accessible is available at a US Centers for Disease Control and Prevention web page. The page explains that "The abbreviations [in] this table (Column 3) were standardized jointly by staff of

1207-440: Is called herd immunity . Polio, which is transmitted only among humans, is targeted by an extensive eradication campaign that has seen endemic polio restricted to only parts of three countries (Afghanistan, Nigeria, and Pakistan). However, the difficulty of reaching all children, cultural misunderstandings, and disinformation have caused the anticipated eradication date to be missed several times. Vaccines also help prevent

1278-454: Is designed to immunize against a single antigen or single microorganism. A multivalent or polyvalent vaccine is designed to immunize against two or more strains of the same microorganism, or against two or more microorganisms. The valency of a multivalent vaccine may be denoted with a Greek or Latin prefix (e.g., bivalent , trivalent , or tetravalent/quadrivalent ). In certain cases, a monovalent vaccine may be preferable for rapidly developing

1349-730: Is elicited by viruses, intracellular bacteria, parasites. The actors here are group 1 innate lymphoid cells (ILC1), NK cells, Th1 cells, macrophages, opsonizing IgG isotypes. Type 2 IR is caused by toxins and multicellular parasites. ILC2, epithelial cells , Th2 lymphocytes, eosinophils, basophils, mast cells, IgE are key players here. Type 3 IR targets extracellular bacteria and fungi by recruiting ILC3, Th17, neutrophils, opsonizing IgG isotypes. Additional types of IR can be observed in noninfectious pathologies. All types of IR have sensor (ILCs, NK cells), adaptive (T and B cells), and effector ( neutrophils , eosinophils , basophils , mast cells ) parts. Vaccine A vaccine

1420-524: Is encountered, the body recognizes the protein coat on the agent, and thus is prepared to respond, by first neutralizing the target agent before it can enter cells, and secondly by recognizing and destroying infected cells before that agent can multiply to vast numbers. Limitations to their effectiveness, nevertheless, exist. Sometimes, protection fails for vaccine-related reasons such as failures in vaccine attenuation, vaccination regimens or administration. Failure may also occur for host-related reasons if

1491-524: Is more effective against bacteria, has a better shelf-life, and improves vaccine stability, potency, and safety; but, in the U.S., the European Union , and a few other affluent countries, it is no longer used as a preservative in childhood vaccines, as a precautionary measure due to its mercury content. Although controversial claims have been made that thiomersal contributes to autism , no convincing scientific evidence supports these claims. Furthermore,

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1562-575: Is prevented. The administration of vaccines is called vaccination . 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 restriction of diseases such as polio , measles , and tetanus from much of the world. The World Health Organization (WHO) reports that licensed vaccines are currently available for twenty-five different preventable infections . The first recorded use of inoculation to prevent smallpox occurred in

1633-539: Is rarely associated with complications in immunodeficient individuals, and rotavirus vaccines are moderately associated with intussusception . At least 19 countries have no-fault compensation programs to provide compensation for those with severe adverse effects of vaccination. The United States' program is known as the National Childhood Vaccine Injury Act , and the United Kingdom employs

1704-641: Is so that in the case that an exposure to the real pathogen occurs, the body can rely on the secondary immune response to quickly defend against it. The innate immune response is an organism's first response to foreign invaders. This immune response is evolutionarily conserved across many different species, with all multi-cellular organisms having some sort of variation of an innate response. The innate immune system consists of physical barriers such as skin and mucous membranes , various cell types like neutrophils , macrophages , and monocytes , and soluble factors including cytokines and complement. In contrast to

1775-423: Is that the adaptive immune response is much slower than the body's innate response because its cells are extremely specific and activation is required before it is able to actually act. In addition to specificity, the adaptive immune response is also known for immunological memory . After encountering an antigen, the immune system produces memory T and B cells which allow for a speedier, more robust immune response in

1846-420: Is the body's second line of defense . The cells of the adaptive immune system are extremely specific because during early developmental stages the B and T cells develop antigen receptors that are specific to only certain antigens . This is extremely important for B and T cell activation. B and T cells are extremely dangerous cells, and if they are able to attack without undergoing a rigorous process of activation,

1917-462: Is the subunit vaccine against hepatitis   B , which is composed of only the surface proteins of the virus (previously extracted from the blood serum of chronically infected patients but now produced by recombination of the viral genes into yeast ). Other examples include the Gardasil virus-like particle human papillomavirus (HPV) vaccine, the hemagglutinin and neuraminidase subunits of

1988-641: The Vaccine Damage Payment . Vaccines typically contain attenuated, inactivated or dead organisms or purified products derived from them. There are several types of vaccines in use. These represent different strategies used to try to reduce the risk of illness while retaining the ability to induce a beneficial immune response. Some vaccines contain live, attenuated microorganisms. Many of these are active viruses that have been cultivated under conditions that disable their virulent properties, or that use closely related but less dangerous organisms to produce

2059-421: The adaptive immune response , the innate response is not specific to any one foreign invader and as a result, works quickly to rid the body of pathogens. Pathogens are recognized and detected via pattern recognition receptors (PRR). These receptors are structures on the surface of macrophages which are capable of binding foreign invaders and thus initiating cell signaling within the immune cell. Specifically,

2130-464: The blood vessels to the infected tissue. Once neutrophils enter the tissue, like macrophages, they are able to phagocytize and kill any pathogens or microbes. Complement , another component of the innate immune system, consists of three pathways that are activated in distinct ways. The classical pathway is triggered when IgG or IgM is bound to its target antigen on either the pathogen cell membrane or an antigen-bound antibody. The alternative pathway

2201-845: The influenza virus, and edible algae vaccines . A subunit vaccine is being used for plague immunization. Certain bacteria have a polysaccharide outer coat that is poorly immunogenic . By linking these outer coats to proteins (e.g., toxins), the immune system can be led to recognize the polysaccharide as if it were a protein antigen. This approach is used in the Haemophilus influenzae type B vaccine . Outer membrane vesicles (OMVs) are naturally immunogenic and can be manipulated to produce potent vaccines. The best known OMV vaccines are those developed for serotype B meningococcal disease . Heterologous vaccines also known as "Jennerian vaccines", are vaccines that are pathogens of other animals that either do not cause disease or cause mild disease in

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2272-451: The lymph node . However, B cell activation is a two-step process. Firstly, B cell receptors, which are just Immunoglobulin M (IgM) and Immunoglobulin D (IgD) antibodies specific to the particular B cell, must bind to the antigen which then results in internal processing so that it is presented on the MHC class II molecules of the B cell. Once this happens a T helper cell which is able to identify

2343-452: The 16th century in China, with the earliest hints of the practice in China coming during the 10th century. It was also the first disease for which a vaccine was produced. The folk practice of inoculation against smallpox was brought from Turkey to Britain in 1721 by Lady Mary Wortley Montagu . The terms vaccine and vaccination are derived from Variolae vaccinae (smallpox of the cow),

2414-518: The CDC further explains that "Upper-case letters in these abbreviations denote full-strength doses of diphtheria (D) and tetanus (T) toxoids and pertussis (P) vaccine. Lower-case "d" and "p" denote reduced doses of diphtheria and pertussis used in the adolescent/adult-formulations. The 'a' in DTaP and Tdap stands for 'acellular', meaning that the pertussis component contains only a part of the pertussis organism." Another list of established vaccine abbreviations

2485-701: The Centers for Disease Control and Prevention, ACIP Work Groups, the editor of the Morbidity and Mortality Weekly Report (MMWR), the editor of Epidemiology and Prevention of Vaccine-Preventable Diseases (the Pink Book), ACIP members, and liaison organizations to the ACIP." Some examples are " DTaP " for diphtheria and tetanus toxoids and acellular pertussis vaccine, "DT" for diphtheria and tetanus toxoids, and "Td" for tetanus and diphtheria toxoids. At its page on tetanus vaccination,

2556-473: The PRRs identify pathogen-associated molecular patterns (PAMPs) which are integral structural components of pathogens. Examples of PAMPs include the peptidoglycan cell wall or lipopolysaccharides (LPS), both of which are essential components of bacteria and are therefore evolutionarily conserved across many different bacterial species. When a foreign pathogen bypasses the physical barriers and enters an organism,

2627-411: The PRRs on macrophages will recognize and bind to specific PAMPs. This binding results in the activation of a signaling pathway which allows for the transcription factor NF-κB to enter the nucleus of the macrophage and initiate the transcription and eventual secretion of various cytokines such as IL-8 , IL-1 , and TNFα . Release of these cytokines is necessary for the entry of neutrophils from

2698-478: The R21/Matrix-M malaria vaccine candidate showed a 72% in sites with seasonal implementation and 67% in sites with age-based implementation in the modified per-protocol analysis. /> In influenza vaccine candidates, Matrix-M was shown to offer cross-protection against multiple strains of influenza . Novavax is also testing a combined flu and COVID-19 vaccine candidate with Matrix-M. This biology article

2769-486: The US. A DNA vaccine uses a DNA plasmid (pDNA)) that encodes for an antigenic protein originating from the pathogen upon which the vaccine will be targeted. pDNA is inexpensive, stable, and relatively safe, making it an excellent option for vaccine delivery. This approach offers a number of potential advantages over traditional approaches, including the stimulation of both B- and T-cell responses, improved vaccine stability,

2840-469: The absence of any infectious agent and the relative ease of large-scale manufacture. Many innovative vaccines are also in development and use. While most vaccines are created using inactivated or attenuated compounds from microorganisms, synthetic vaccines are composed mainly or wholly of synthetic peptides, carbohydrates, or antigens. Vaccines may be monovalent (also called univalent ) or multivalent (also called polyvalent ). A monovalent vaccine

2911-475: The amount of serotype   2 virus in the vaccine had to be reduced to stop it from interfering with the "take" of the serotype   1 and   3 viruses in the vaccine. It was also noted in a 2001 study to be a problem with dengue vaccines, where the DEN-3 serotype was found to predominate and suppress the response to DEN-1, -2 and -4 serotypes. Vaccines typically contain one or more adjuvants , used to boost

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2982-433: The antigen bound to the MHC interacts with its co-stimulatory molecule and activates the B cell. As a result, the B cell becomes a plasma cell which secretes antibodies that act as an opsonin against invaders. Specificity in the adaptive branch is due to the fact that every B and T cell is different. Thus there is a diverse community of cells ready to recognize and attack a full range of invaders. The trade-off, however,

3053-482: 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. Vaccines can be prophylactic (to prevent or alleviate the effects of a future infection by a natural or "wild" pathogen ), or therapeutic (to fight a disease that has already occurred, such as cancer ). Some vaccines offer full sterilizing immunity , in which infection

3124-408: The case that the organism ever encounters the same antigen again. Depending on exogenous demands, several types of immune response (IR) are distinguished. In this paradigm, immune system (both innate and adaptive) and non-immune system cellular and molecular components are organized to optimally respond to distinct exposome challenges. Currently, several types of IR are classified. Type 1 IR

3195-424: The case that the same pathogen enters the organism again. If the organism does happen to become re-exposed to the same pathogen, a secondary immune response will kick in and the immune system will be able to respond in both a fast and strong manner because of the memory cells from the first exposure. Vaccines introduce a weakened, killed, or fragmented microorganism in order to evoke a primary immune response. This

3266-528: The co-stimulatory molecules, the adaptive immune response would be inefficient and T cells would become anergic . Several T cell subgroups can be activated by specific APCs, and each T cell is specially equipped to deal with each unique microbial pathogen. The type of T cell activated and the type of response generated depends, in part, on the context in which the APC first encountered the antigen. Once helper T cells are activated, they are able to activate naïve B cells in

3337-503: The development of antibiotic resistance. For example, by greatly reducing the incidence of pneumonia caused by Streptococcus pneumoniae , vaccine programs have greatly reduced the prevalence of infections resistant to penicillin or other first-line antibiotics. The measles vaccine is estimated to prevent a million deaths every year. Vaccinations given to children, adolescents, or adults are generally safe. Adverse effects, if any, are generally mild. The rate of side effects depends on

3408-425: The eradication of smallpox , one of the most contagious and deadly diseases in humans. Other diseases such as rubella, polio , measles, mumps, chickenpox , and typhoid are nowhere near as common as they were a hundred years ago thanks to widespread vaccination programs. As long as the vast majority of people are vaccinated, it is much more difficult for an outbreak of disease to occur, let alone spread. This effect

3479-416: The finished product, as they may in the environment and population as a whole. Many vaccines need preservatives to prevent serious adverse effects such as Staphylococcus infection, which in one 1928 incident killed 12 of 21 children inoculated with a diphtheria vaccine that lacked a preservative. Several preservatives are available, including thiomersal, phenoxyethanol , and formaldehyde . Thiomersal

3550-541: The general population, a high standard of safety is required. As part of a multinational licensing of a vaccine, the World Health Organization Expert Committee on Biological Standardization developed guidelines of international standards for manufacturing and quality control of vaccines, a process intended as a platform for national regulatory agencies to apply for their own licensing process. Vaccine manufacturers do not receive licensing until

3621-555: The health of the host organism if not cleared from the body. In addition, there are other forms of immune response. For example, harmless exogenous factors (such as pollen and food components) can trigger allergy ; latex and metals are also known allergens. A transplanted tissue (for example, blood) or organ can cause graft-versus-host disease . A type of immune reactivity known as Rh disease can be observed in pregnant women. These special forms of immune response are classified as hypersensitivity . Another special form of immune response

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3692-434: The host can still become infected. Once antibodies are produced, they may promote immunity in any of several ways, depending on the class of antibodies involved. Their success in clearing or inactivating a pathogen will depend on the amount of antibodies produced and on the extent to which those antibodies are effective at countering the strain of the pathogen involved, since different strains may be differently susceptible to

3763-414: The host's immune system does not respond adequately or at all. Host-related lack of response occurs in an estimated 2-10% of individuals, due to factors including genetics, immune status, age, health and nutritional status. One type of primary immunodeficiency disorder resulting in genetic failure is X-linked agammaglobulinemia , in which the absence of an enzyme essential for B cell development prevents

3834-411: The host's immune system from generating antibodies to a pathogen . Host–pathogen interactions and responses to infection are dynamic processes involving multiple pathways in the immune system. A host does not develop antibodies instantaneously: while the body's innate immunity may be activated in as little as twelve hours, adaptive immunity can take 1–2 weeks to fully develop. During that time,

3905-417: The immune response. Tetanus toxoid, for instance, is usually adsorbed onto alum . This presents the antigen in such a way as to produce a greater action than the simple aqueous tetanus toxoid. People who have an adverse reaction to adsorbed tetanus toxoid may be given the simple vaccine when the time comes for a booster. In the preparation for the 1990 Persian Gulf campaign, the whole cell pertussis vaccine

3976-430: The immunodominant antigen of the pathogen or a surface protein that enables the formation of neutralizing antibodies. The subgroup of genetic vaccines encompass viral vector vaccines, RNA vaccines and DNA vaccines. Viral vector vaccines use a safe virus to insert pathogen genes in the body to produce specific antigens , such as surface proteins , to stimulate an immune response . An mRNA vaccine (or RNA vaccine )

4047-448: The microorganism. Examples of toxoid-based vaccines include tetanus and diphtheria . Not all toxoids are for microorganisms; for example, Crotalus atrox toxoid is used to vaccinate dogs against rattlesnake bites. Rather than introducing an inactivated or attenuated microorganism to an immune system (which would constitute a "whole-agent" vaccine), a subunit vaccine uses a fragment of it to create an immune response. One example

4118-407: The new protective inoculations then being developed. The science of vaccine development and production is termed vaccinology . There is overwhelming scientific consensus that vaccines are a very safe and effective way to fight and eradicate infectious diseases. The immune system recognizes vaccine agents as foreign, destroys them, and "remembers" them. When the virulent version of an agent

4189-440: The number of cases dropped to fewer than 150 per year (median of 56). In early 2008, there were 64 suspected cases of measles. Fifty-four of those infections were associated with importation from another country, although only thirteen percent were actually acquired outside the United States; 63 of the 64 individuals either had never been vaccinated against measles or were uncertain whether they had been vaccinated. Vaccines led to

4260-491: The only childhood vaccine in the U.S. that contains thiomersal in greater than trace amounts is the influenza vaccine, which is currently recommended only for children with certain risk factors. Single-dose influenza vaccines supplied in the UK do not list thiomersal in the ingredients. Preservatives may be used at various stages of the production of vaccines, and the most sophisticated methods of measurement might detect traces of them in

4331-400: The organism being treated. The classic example is Jenner's use of cowpox to protect against smallpox. A current example is the use of BCG vaccine made from Mycobacterium bovis to protect against tuberculosis . Genetic vaccines are based on the principle of uptake of a nucleic acid into cells, whereupon a protein is produced according to the nucleic acid template. This protein is usually

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4402-437: The severity of infection and response to a vaccine. Elderly (above age 60), allergen-hypersensitive , and obese people have susceptibility to compromised immunogenicity , which prevents or inhibits vaccine effectiveness, possibly requiring separate vaccine technologies for these specific populations or repetitive booster vaccinations to limit virus transmission . Severe side effects are extremely rare. Varicella vaccine

4473-457: The severity of infection, resulting in a lower mortality rate , lower morbidity , faster recovery from illness, and a wide range of other effects. Those who are older often display less of a response than those who are younger, a pattern known as Immunosenescence . Adjuvants commonly are used to boost immune response, particularly for older people whose immune response to a simple vaccine may have weakened. The efficacy or performance of

4544-520: The skin and mucous membranes, immune cells such as neutrophils , macrophages , and monocytes , and soluble factors including cytokines and complement . On the other hand, the adaptive branch is the body's immune response which is catered against specific antigens and thus, it takes longer to activate the components involved. The adaptive branch include cells such as dendritic cells , T cell , and B cells as well as antibodies —also known as immunoglobulins—which directly interact with antigen and are

4615-496: The successful conclusion of the development cycle and further the clinical trials and other programs involved through Phases   I–III demonstrating safety, immunoactivity, immunogenetic safety at a given specific dose, proven effectiveness in preventing infection for target populations, and enduring preventive effect (time endurance or need for revaccination must be estimated). Because preventive vaccines are predominantly evaluated in healthy population cohorts and distributed among

4686-510: The term devised by Edward Jenner (who both developed the concept of vaccines and created the first vaccine) to denote cowpox . He used the phrase in 1798 for the long title of his Inquiry into the Variolae vaccinae Known as the Cow Pox , in which he described the protective effect of cowpox against smallpox. In 1881, to honor Jenner, Louis Pasteur proposed that the terms should be extended to cover

4757-420: The three pathways ensures that complement will still be functional if one pathway ceases to work or a foreign invader is able to evade one of these pathways ( defense in depth principle). Though the pathways are activated differently, the overall role of the complement system is to opsonize pathogens and induce a series of inflammatory responses that help to combat infection . The adaptive immune response

4828-574: The vaccine in question. Some common side effects include fever, pain around the injection site, and muscle aches. Additionally, some individuals may be allergic to ingredients in the vaccine. MMR vaccine is rarely associated with febrile seizures . Host-("vaccinee")-related determinants that render a person susceptible to infection, such as genetics , health status (underlying disease, nutrition, pregnancy, sensitivities or allergies ), immune competence , age, and economic impact or cultural environment can be primary or secondary factors affecting

4899-413: The vaccine is dependent on several factors: If a vaccinated individual does develop the disease vaccinated against ( breakthrough infection ), the disease is likely to be less virulent than in unvaccinated cases. Important considerations in an effective vaccination program: In 1958, there were 763,094 cases of measles in the United States; 552 deaths resulted. After the introduction of new vaccines,

4970-772: The vaccine. The live attenuated vaccine containing strain Yersinia pestis EV is used for plague immunization. Attenuated vaccines have some advantages and disadvantages. Attenuated, or live, weakened, vaccines typically provoke more durable immunological responses. But they may not be safe for use in immunocompromised individuals, and on rare occasions mutate to a virulent form and cause disease. Some vaccines contain microorganisms that have been killed or inactivated by physical or chemical means. Examples include IPV ( polio vaccine ), hepatitis A vaccine , rabies vaccine and most influenza vaccines . Toxoid vaccines are made from inactivated toxic compounds that cause illness rather than

5041-448: Was used as an adjuvant for anthrax vaccine. This produces a more rapid immune response than giving only the anthrax vaccine, which is of some benefit if exposure might be imminent. Vaccines may also contain preservatives to prevent contamination with bacteria or fungi . Until recent years, the preservative thiomersal ( a.k.a. Thimerosal in the US and Japan) was used in many vaccines that did not contain live viruses. As of 2005,

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