Pneumococcal polysaccharide vaccine

Pneumococcal polysaccharide vaccine (PPSV)—the latest version known as Pneumovax 23 (PPV-23)—is the first pneumococcal vaccine derived from a capsular polysaccharide, and an important landmark in medical history. The polysaccharide antigens were used to induce type-specific antibodies that enhanced opsonization, phagocytosis, and killing of Streptococcus pneumoniae (pneumococcal) bacteria by phagocytic immune cells. The pneumococcal polysaccharide vaccine is widely used in high-risk adults. As a result, there have been important reductions in the incidence, morbidity, and mortality from invasive pneumococcal disease. Pneumococcal polysaccharide vaccine (PPSV)—the latest version known as Pneumovax 23 (PPV-23)—is the first pneumococcal vaccine derived from a capsular polysaccharide, and an important landmark in medical history. The polysaccharide antigens were used to induce type-specific antibodies that enhanced opsonization, phagocytosis, and killing of Streptococcus pneumoniae (pneumococcal) bacteria by phagocytic immune cells. The pneumococcal polysaccharide vaccine is widely used in high-risk adults. As a result, there have been important reductions in the incidence, morbidity, and mortality from invasive pneumococcal disease. First used in 1945, the tetravalent vaccine was not widely distributed, since its deployment coincided with the discovery of penicillin. In the 1970s, Robert Austrian championed the manufacture and distribution of a 14-valent PPSV. This evolved in 1983 to a 23-valent formulation (PPSV23). A significant breakthrough affecting the burden of pneumococcal disease was the licensing of a protein conjugate heptavalent vaccine (PCV7) beginning in February 2000. In the United States, PPSV is recommended for adults 65 years of age or older, adults with serious long-term health problems, smokers, children older than two years with serious long-term health problems, giving the protection of 5 years or more. The World Health Organization recommendations are similar. The WHO does not recommend use of PPV in routine childhood immunization programs. Pneumococcal vaccine is beneficial to control exacerbations of chronic obstructive pulmonary disease (COPD) and asthma. In March 2011, The Joint Committee on Vaccination and Immunisation (JCVI) of the United Kingdom advised to stop using PPSV, for those aged 65 years and older. However, as of 2013, the Green Book, which is the United Kingdom's official government recommendations on immunizations, still carried the recommendation to give PPSV to those aged 65 and over. PPSV should be offered to those in clinical risk groups. PPSV is important for those with HIV/AIDS. In Canadian HIV patients, the vaccine has been reported to decrease the incidence of invasive pneumococcal disease from 768/100,000 person-years to 244/100,000 patient-years. Current WHO guidelines recommend immunization with PPV-23 for HIV patients in clinical stage 1, while the CDC recommends immunization in those with a CD4 cell count greater than 200/μL. Approximately half of people who receive PPSV experience pain and soreness at the vaccination site. Fewer than one percent develop a fever and/or muscle aches. The 23-valent vaccine (e.g., Pneumovax 23) is effective against 23 different pneumococcal capsular types (serotypes 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F and 33F), and so covers 90 percent of the types found in pneumococcal bloodstream infections. Children under the age of two years fail to mount an adequate response to the 23-valent adult vaccine, and instead a 13-valent Pneumococcal Conjugated Vaccine (PCV) (e.g. Prevnar 13) must be used. Prevnar 13 is a new vaccine which has replaced Prevnar 7, adding six new serotypes to the vaccine. While this covers only thirteen strains out of more than ninety strains, these thirteen strains caused 80 percent to 90 percent of cases of severe pneumococcal disease in the US before introduction of the vaccine, and it is considered to be nearly 100 percent effective against these strains.