Immunity polysaccharide vaccines

PCV 7, 7-valent pneumococcal conjugated vaccine PPV 23, 23-valent pneumococcal polysaccharide vaccine. From Advisory Committee on Immunization Practices,18 Committee on Infectious Diseases,16 and Sickle Cell Disease Care Consortium.27... 

Three typhoid vaccines are available currently for use in the United States (1) an oral live-attenuated vaccine (Vivotif Berna-TM vaccine, Swiss Serum and Vaccine Institute), (2) a parenteral heat-phenol-inactivated vaccine (Typhoid Vaccine, Wyeth-Ayerst), and (3) a parenteral capsular polysaccharide vaccine (Typhim Vi, Pasteur Merieux). Immunization is recommended only for travelers going to endemic areas such as Latin America, Asia, and Africa household contacts of a chronic carrier and laboratory personnel who frequently work with S. typhi.13... 

The 23-valent pneumococcal polysaccharide vaccine contains 23 serotypes that are responsible for causing more than 80% of invasive S. pneumoniae infections in adults. The vaccine includes those serotypes that are associated with drug resistance. Use of the vaccine will not prevent the development of antibiotic-resistant S. pneumoniae, but is likely to prevent infection from drug-resistant strains. The 23-valent pneumococcal polysaccharide vaccine has demonstrated good immunogenicity in adults, but an individual will not develop immunity to all 23 serotypes following vaccination.10... 

Meningococcal Polysaccharide Vaccine (Menomune A/C/Y/ W-135) Uses Immunize against N. meningitidis Action Active immunization )o ei Adults Feds >2y. 0.5 mL SQ (not IM, intradOTnaUy, IV) may rqieat... 

Pneumococcal Polysaccharide. Pneumococcal polysaccharide vaccine may be used for immunization of persons two years of age or older who are at increased risk of pneumococcal disease. 

S. pneumoniae has more than 80 sero-types. The current polysaccharide vaccine consists of 23 serotypes and covers about 87% of all pneumococcal diseases in the United States. Current vaccine development is based on conjugate technology and concentrates on die most prevalent 7-9 serotypes. Three multivalent vaccine candidates are in clinical trials. All are based on conjugating the polysaccharide to a T-dependent protein carrier. The results of phase 1 and 11 trials in infants have demonstrated the safety and immnnogenicity of these vaccines. Phase. Ill trials to demonstrate efficacy are in progress and final approval of this vaccine for infant immunization will be by the year 2000. 

An important distinction must be made between the humoral response to a pure, capsular polysaccharide, and to the same polysaccharide when it is an integral part of the bacterium. Thus, the immunity received on recovery from infection by encapsulated bacteria, in terms of the polysaccharide antigen, differs from that generated by purposeful immunization with purified capsular-polysaccharide vaccines. Fortunately, with the exception of infants, the polysaccharide vaccines still stimulate protective-antibody levels in humans, despite these differences. In infants, due to the immature nature of their immune systems, these polysaccharide vaccines are of only marginal benefit.7 Some insights into the nature of these different responses in humans can be found in studies on the cellular basis of the immune response to polysaccharides. However, for the purposes of this Chapter, it would be inappropriate to provide a lengthy description of this incompletely understood mechanism in-depth reviews of this burgeoning field of research can be referred to.144-147,162-166... 

During an immunization campaign with a polysaccharide vaccine in 130 000 children in Auckland, New Zealand, there were 92 reports of apparent peripheral nerve involvement, including 80 reports of unexplained weakness and 57 reports of paresthesia or dysesthesia (12). 

The question of whether revaccination with 23-valent pneumococcal polysaccharide vaccine (PPV) at least 5 years after the first vaccination is associated with more frequent or more serious adverse events than those after the first vaccination has been studied in patients aged 50-74 years who had never been vaccinated with PPV (n = 901) or who had been vaccinated once at least 5 years before enrolment (n = 513) (8). After one dose of PPV, local injection site reactions and prevaccination concentrations of type-specific antibodies were measured. Those who were re-vaccinated were more likely than those who received their first vaccinations to report a local injection site reaction of at least 10.2 cm (4 in.) in diameter within 2 days of vaccination (55/513 versus 29/ 901, or 11 versus 3%). The reactions resolved by a median of 3 days after vaccination. The highest rate was among revaccinated patients who were immune competent and did not have chronic illnesses 15% (33/228) compared with 3% (10/337) among comparable patients receiving their first vaccinations. The risk of these local reactions correlated significantly with prevaccination geometric mean antibody concentrations. The authors concluded that physicians and patients should be aware that selflimited local injection site reactions occur more often after revaccination compared with a first vaccination however, this risk does not represent a contraindication to revaccination with PPV in recommended patients. 

The efficacy of polysaccharide vaccine in preventing invasive pnenmococcal disease, pnenmonia, and death has been assessed in a donble-blind, randomized, placebo-controlled trial in 1392 HIVl-infected adnlts in Uganda (14). The vaccine was well tolerated. However, it was ineffective and is not recommended for nse in HIVl-infected indivi-dnals. Reassessment of recommendations for polysaccharide vaccine immunization may be necessary in some countries. The authors suggested that the vaccine causes destruction of polysaccharide-responsive B cell clones. 

In another clinical trial the immunogenicity and safety of polysaccharide vaccine has been assessed in 21 renal transplant recipients (15). Protective antibody titers were reached at 6 and 12 weeks after immunization in aU recipients, bar one. No local or systemic adverse effects were observed. 

Arthus reactions and systemic reactions have commonly been reported after booster doses of polysaccharide vaccine and are thought to result from antigen-antibody reactions involving antibodies induced by the previous immunization (16). Data on revaccination of children are not yet sufficient to provide a basis for recommendation. 

Kazancioglu R, Sever MS, Yuksel-Onel D, Eraksoy H, Yildiz A, Cehk AV, Kayacan SM, Badur S. Immunization of renal transplant recipients with pneumococcal polysaccharide vaccine. Clin Transplant 2000 14(l) 61-5. 

Capsular polysaccharides purified from bacteria are almost non-toxic and considerably less toxic than the whole-cell and elicited anti-polysaccharide antibodies at a single dose of 10-50 pg [17]. The antibodies provide type-specific immunity lasting for several years in healthy humans [18]. The simplicity of polysaccharides as vaccines and its low toxicity prompted development of the first polysaccharidic pneumococcal vaccine (tetravalent) marketed as early as 1946 [19]. Polysaccharide vaccines were only really introduced during the 1970s to counteract the emergence of bacterial resistance to antibiotics. 

In vivo assessment of B-lymphocyte function involves immunizing the patient with a protein (e.g., tetanus toxoid) and a polysaccharide (e.g., pneumococcal polysaccharide vaccine) antigen to elicit and... 

Two different pneumococcal vaccines are available. The 7-valent pneumococcal conjugate vaccine (PCV 7 Prevnar) induces good antibody responses in infants. Immunization with the PCV 7 is recommended for all children less than 24 months of age. Infants should receive the first dose between 6 weeks and 6 months. Two additional doses should be given at approximately 2-month intervals, followed by a fourth dose at age 12 to 15 months. The 23-valent pneumococcal polysaccharide vaccine (PPV 23 Pneumovax 23) was not recommended for use in children less than 2 years of age because... 

Vaccines also may be used to boost specific immune processes directed against the bacteria themselves or against adherence appendages, cytotoxins, or enterotoxins. Currently available vaccines for typhoid fever in the United States are the parenteral Vi capsular polysaccharide vaccine, the oral live-attenuated Ty21a vaccine, and the older heat-phenol-inactivated parenteral vaccine. Only the older parenteral cholera vaccine is licensed for use in the United States, but it is not recommended owing to the low risk of cholera to the traveler and the limited efficacy of the vaccine. New oral five and killed vaccines are licensed outside the United States and are used by some travelers. The rotavirus vaccine, although effective, has presented complications in the form of rare cases of intussusceptions it is no longer marketed and thus is not recommended. ... 

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