Vaccination diseases

French Ministry of Health. Press release, 23 May 2000. Compensation for hepatitis B vaccination. http www.who.int/vaccines-diseases/safety/hottop/hepb.htm (accessed 2 August 2000). 

World Health Organization. Vaccines and Biologicals. Diabetes. http //www.who.int/vaccines-diseases/safety/ infobank/diabetes.shtml, 29/11/2003. 

DALY, J.G., GRIFFITHS, S.G., KEW, A.K., MOORE, A.R. and OLIVIER, G. (2001) Characterization of attenuated Renibacterium salmoninarum strains and their use as live vaccines. Diseases of Aquatic Organisms 44,121-126. 

Center for Biologies Evaluation and Research (CBER). This center is responsible for the regulation and approval of ah biological products intended for use in the treatment, prevention, or cure of diseases or injuries to humans. A biological product is any vims, therapeutic semm, toxin, antitoxin, vaccine, blood or blood component or derivative, or analogous product (5). It also includes products produced by biotechnology, such as interferons and erythropoietins. 

A vaccine is a preparation used to prevent a specific infectious disease by inducing immunity in the host against the pathogenic microorganism. The practice is also called immunization. The first human immunization was performed in 1796 by Edward Jenner in England which led to the discovery of smallpox vaccine. However, classical vaccinology developed 100 years later, after the work by Louis Pasteur demonstrated that microorganisms are causes of diseases. 

During the early 1900s, vaccines against major human epidemic diseases such as pertussis, diphtheria, tetanus, and tuberculosis were developed. Vaccines for many animal diseases were also available. In the early 1950s, the development of cell culture techniques byj. E. Enders at Harvard was followed by another series of major advances in vaccine development. Vaccines against poHo, mumps, measles, and mbeUa were Hcensed during the 1960s. 

Preventive medicine through vaccination continues to be the most cost-effective pubHc health practice, even with the drastic advance in modern medicine. Mass vaccination programs have eradicated smallpox from the earth. The World Health Organization (WHO) has a major campaign underway to eradicate poHo by the year 2000. The development of vaccines has saved millions of Hves and prevented many more from suffering. However, there are stiU many diseases without effective vaccines, such as malaria. With the recent emergence of antibiotic-resistance strains and exotic vimses, an effective vaccine development program becomes a top priority of pubHc health poHcy. 

Live vaccines are normally weakened strains that do not cause diseases in the host, but stiU can stimulate the immune response. A typical example is the poho vaccine. The weakening of microorganisms or attenuation of the vims or bacteria can be accompHshed by passage through different substrates and/or at different temperatures. Modem genetic engineering techniques can also be used to attenuate a vims or bacterium. 

Vaccines are used in either the general population of children or adults or for special groups. Recommendations for vaccine usage are made by the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control. The Committee on Infectious Diseases of the American Academy of Pediatrics (Redbook Committee) also makes recommendations for infants through adolescents, and the American Academy of Family Physicians makes recommendations for adults. An excellent review of vaccine history, development, usage, and related regulatory issues is available (2). 

Hepatitis B. Although Hepatitis B (Hep B) is not an infant disease, it is recommended for infant immunization to better control spread, because compliance with vaccine immunization programs is easier to achieve Hi an infant population. Infants receive immunizations at bHth, 1—2 months. 

Influenza. The ACIP recommends annual influenza vaccination for all persons who are at risk from infections of the lower respiratory tract and for all older persons. Influen2a vimses types A and B are responsible for periodic outbreaks of febrile respiratory disease. 

Composition and Methods of Manufacture. Two types of influen2a vimses, A and B, are responsible for causing periodic outbreaks of febrile respiratory disease. The manufacture of an effective vaccine is compHcated by antigenic variation or drift, which can occur from year to year within the two vims types, making the previous year s vaccine less effective. Each year, antigenic characteri2ation is important for selecting the vims strains to be included in the vaccine. 

Indications for Use. Pneumococcal polysaccharide vaccine maybe used for immuni2ation of persons two years of age or older who are at increased risk of pneumococcal disease. 

Composition and Methods of Manufacture. The vaccine consists of a mixture of purified capsular polysaccharides from 23 pneumococcal types that are responsible for over 90% of the serious pneumococcal disease in the world (47,48). Each of the polysaccharide types is produced separately and treated to remove impurities. The latter is commonly achieved by alcohol fractionation, centrifugation, treatment with cationic detergents, proteolytic en2ymes, nucleases or activated charcoal, diafiltration, and lyophili2ation (49,50). The vaccine contains 25 micrograms of each of the types of polysaccharide and a preservative such as phenol or thimerosal. 

Rotavirus. Rotavims causes infant diarrhea, a disease which has major socio-economic impact. In developing countries it is the major cause of death in infants worldwide, causing up to 870,000 deaths per year. In the United States, diarrhea is stiU a primary cause of physician visits and hospitalization, although the mortaUty rate is relatively low. Studies have estimated a substantial cost benefit for a vaccination program in the United States (67—69). Two membrane proteins (VP4 and VP7) of the vims have been identified as protective epitopes and most vaccine development programs are based on these two proteins as antigens. Both Hve attenuated vaccines and subunit vaccines are being developed (68). 

Respiratory Syncytial Virus. Respiratory syncytial vims (RSV) causes severe lower respiratory tract disease in infants. It is the major cause of hospitalization in the United States (- 90,000 events/yr) and it has a high mortaUty rate in neonates and other high risk populations, such as the geriatric population (51). Development of an RSV vaccine has always been a major priority, however, earlier attempts have mostiy failed (70). 

Vaccine development is hampered by the fact that recurrent disease is common. Thus, natural infection does not provide immunity and the best method to induce immunity artificially is not clear. The genome of these vimses is also able to cause transformation of normal cells, thus conferring on them one of the properties attributed to cancerous cells. Vaccine made from herpes vimses must, therefore, be carefully purified and screened to eliminate the possibihty of including any active genetic material. 

Malaria. Malaria infection occurs in over 30% of the world s population and almost exclusively in developing countries. Approximately 150 X 10 cases occur each year, with one million deaths occurring in African children (87). The majority of the disease in humans is caused by four different species of the malarial parasite. Vaccine development is problematic for several reasons. First, the parasites have a complex life cycle. They are spread by insect vectors and go through different stages and forms (intercellular and extracellular sexual and asexual) as they grow in the blood and tissues (primarily fiver) of their human hosts. In addition, malaria is difficult to grow in large quantities outside the natural host (88). Despite these difficulties, vaccine development has been pursued for many years. An overview of the state of the art is available (89). 

The worldwide market is approximately 3.0 bHHon in sales, with the pediatric portion accounting for about 35%. Basic, required childhood vaccines (DTP, poHo, measles /MMR, BCG, and TT) account for 3640 x 10 doses of this global market. In the United States doses distributed in the pediatric sector have risen from around 45 x 10 in 1982, covering basic, childhood vaccines, to around 75 x 10 in 1993 due primarily to the addition of vaccines for Haemophilus disease, hepatitis B, and a second dose of MMR to the recommended childhood series (144). The majority of vaccines for the U.S. market are... 

P. J. Baker, ed.. National Institute of Allergy and Infectious Diseases, The Jordan Report, Accelerated Development of Vaccines, 1993, NIH, Bethesda, Md. 

The prophylactic stimulation of the immune system using vaccines and bacterins is time-consuming. Of even greater value would be the abiUty to activate the system to combat a disease attack already underway, or to be able to increase the response to abnormal cells and neutralize neoplasia in any organ of the body. Several compounds, some unique entities and some already in use for other purposes, have shown potential utiUty as such nonspecific immune stimulants. 

In 1971, levamisole, an anthelmintic compound widely used in catde and swine, was shown to improve the effects of an experimental Brucella abortus vaccine in mice. Since that time, the veterinarians and physicians have explored the effects of levamisole in such diverse areas as arthritis, lupus erythematosis, cancer therapy, respiratory diseases, Newcastle disease, foot-and-mouth disease, mastitis, and vaccine potentiation. Although the exact mechanism of action has as yet not been deterrnined there is substantial evidence that, under defined circumstances, levamisole can augment the animal s natural immune response (9). New immunostimulants include Staph Ijysate acemannon, NLAB-31. 

The nature of the conditions of intensive production, however, can increase the risk of diseases and infections which can spread very rapidly and devastate large numbers of animals." Thus it is common practice for producers of poultry to add coccidiostats to their diets and vaccines to their drinking water in order to prevent coccidiosis and other infectious diseases such as bronchitis and Newcastle disease. A similar problem exists for intensively reared fish, where it is necessary to add antibiotics to their diets. A problem with intensively reared fish is that their diet is added directly into the water in which they live thus drugs and other additives in the diet are relatively easily dispersed into the local environment of fish farms, where they can increase bacterial resistance and also cause problems such as algal blooms. 

The public s idea of what is most risky usually differs widely from the facts. Much of this stems from disproportionate media coverage of newsworthy hazards that are rare or unusual. This distorts many people s perspective on the relative magnitude of risks. Thus, some parents may not have their children vaccinated, fearing a rare reaction to the vaccine more than the overwhelmingly greater risk of dying from the disease. 

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