Bacterial vaccines combined

The single-component bacterial vaccines are listed in Table 15.1. For each vaccine, notes are provided of the basic material fkm which the vaccine is made, the salient production processes and tests for potency and for safety. The multicomponent vaccines that are made by blending together two or more of the single component vaccines are required to meet the potency and safety requirements for each of the single components that they contain. The best known of the combined bacterial vaccines is the adsorbed diphtheria, tetanus and pertussis vaccine (DTPerWac/Ads) that is used to immunize infants, and the adsorbed diphtheria and tetanus vaccine (DTWac/Ads) that is used to reinforce the immunity of school entrants. 

The single-component viral vaccines are listed in Table 15.2 with notes similar to those provided with the bacterial vaccines. The only eombined viral vaeeine that is widely used is the measles, mumps and rubella vaccine (MMR Vac). In a sense, however, both the inactivated (Salk) poliovaccine (PoWac (inactivated)) and the live (Sabin) poliovaccine (PolWac (oral)) are combined vaccines in that they are both mixtures of vims of each of the three serotypes of poliovims. Influenza vaeeines, too, are eombined vaccines in that many contain components fiom as many as three vims strains, usually fiom two strains of influenza A and one strain of influenza B. 

Combination of viral and bacterial antigens (e.g., multivalent viral and bacterial vaccines, and so on) This subclass is indented under subclass 184.1. Subject matter involving a combination of viral and bacterial antigens, such as that found in a multivalent viral and bacterial vaccine. 

A number of B. pertussis (polypeptide) antigens have been expressed in E. coli and other recombinant systems. Several of these are being evaluated as potential subunit vaccines, including B. pertussis surface antigen, adhesion molecules and pertussis toxin. Pertussis toxin has been shown to protect mice from both aerosol and intracerebral challenge with virulent B. pertussis. The bacterial proteins that mediate surface adhesion protect mice from aerosol but not intracerebral challenge. Future pertussis subunit vaccines may well contain a combination of two or more pathogen-derived polypeptides. 

To some extent the simplest vaccines are those in which the bacterial or viral pathogens has been killed by chemicals or heat so that they themselves cannot cause disease but can confer protection against invasion. This has been used, for example, for the combined diphtheria-tetanus-pertussis vaccine. In this case there were concerns about the presence of entire cells that could cause complications other than the needed protection. Recently acellular systems have been introduced which may... 

In the early 20th century it was recognized that some components of a microbacterial cell were more important than others for protection and thus came the concept of subunit vaccines. When combined with the discovery that bacterial toxins could be inactivated with formaldehyde, the result was the introduction of a diphtheria subunit vaccine in 1923 and a tetanus subunit vaccine in 1927. 

Bacterial toxins such as diphtheria and tetanus can damage host cells but the isolated toxins can also be immunogenic. However, the induced response may not always be very strong and booster shots are required every 10 years. Adjuvants could improve the response and both diphtheria and tetanus toxoids are more effective when combined with pertussis subunit vaccines, the DPT combination at present used clinically. 

Diphtheria, Tetanus, and Pertussis. These vaccines in combination (DTP) have been routinely used for active immunization of infants and young children since the 1940s. The recommended schedule calls for immunizations at 2, 4, and 6 months of age widi boosters at 18 months and 4-5 years of age. Since 1993 these vaccines have been available in combination with a vaccine that protects against Haemophilus disease, thus providing protection against four bacterial diseases in one preparation. A booster immunization with diphtheria and tetanus only is recommended once every 10 years after the fifth dose. 

It has been possible to produce vaccines to use for immunization against certain bacterial infections and other human diseases. Staphylococcus aureus capsular polysaccharide in combination with a carrier protein has been used to prepare monovalent vaccines specific for S. aureus [86], The vaccine was administered to groups of healthy adults and to patients with end-stage renal disease. The antibodies are directed at the polysaccharide moiety of the glycoconjugate. The data of this study show that conjugate-induced antibodies to S. aureus can provide partial protection against S. aureus bacteremia, Fig. (45). 

The pertussis vaccine is another example where, traditionally, whole bacterial cells have been used, but recent developments have led to an acellular pertussis vaccine that may contain detoxified toxin, either alone or combined with several other bacterial antigens. 

Acellular pertussis vaccines contain selective components of the B. pertussis organism. All acellular vaccines contain pertussis toxin (PT), and some contain one or more additional bacterial components (e.g., filamentous hemagglutinin [FHA], pertactin [a 69-kDa outer membrane protein], and fimbriae types 2 and 3). Acellular pertussis vaccine is recommended for all doses of the pertussis schedule at 2, 4, 6, and 15 to 18 months of age. A fifth dose of permssis vaccine is given to children 4 to 6 years of age. Pertussis vaccine is administered in combination with diphtheria and tetanus (DTaP). Although the permssis vaccine is not recommended for individuals 7 years of age and older, booster doses for adolescents and adults may be incorporated into future recommendations because members of these groups are important reservoirs of infection. 

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