ACIP clarifies PPV23 revaccination for high-risk children.
ATLANTA -- Vaccination with 23-valent pneumococcal polysaccharide vaccine should be given 5 years after vaccination with 7-valent pneumococcal conjugate vaccine in high-risk children, the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices agreed at its fall meeting.
The purpose of the vote was to clarify existing recommendations, which called for an interval of 3-5 years between vaccinations in this population, despite a lack of data on revaccination safety and the best timing for revaccination, according to Dr. Pekka Nuorti of the CDC, who presented the recommendation on behalf of the Pneumococcal Vaccines Workgroup.
"'The [3- to 5-year interval] recommendation causes confusion among providers as to which time period is recommended," he said, noting that the suggestion that a 3-year interval might be warranted in some children was based on data from studies conducted several years ago that indicated some children had rapid declines in antibodies following initial vaccination.
However, those studies predated the availability of more sensitive and specific assays, he said.
The one-time, 5-year revaccination interval approved by the ACIP applies to those aged 2 years and older who are immunocompromised, have sickle cell disease, or have functional or anatomic asplenia.
These individuals are at highest risk for serious pneumococcal infection and may have a rapid decline in pneumococcal antibody levels after initial vaccination.
The 23-valent pneumococcal polysaccharide vaccine (PPV23) has been shown to provide excellent booster response in healthy children to the seven serotypes found in both the 7-valent pneumococcal conjugate vaccine (PCV7) and in PPV23. The intent of revaccination with PPV23 in high-risk children is to target the 16 serotypes included in PPV23 to better protect those who were previously vaccinated with PCV7.
The work group based its recommendation in part on the possibility that immunologic responses to PPV23 are improved in older children and also on the possibility that a longer interval between doses may reduce immunologic hyper-responsiveness, said Dr. Nuorti.
In other PPV23-related business, the committee also addressed revaccination in American Indians and Alaska Natives, who may have high rates of invasive pneumococcal disease. Vaccination is routine in those aged 24-59 months with medical conditions that are PPV23 indications, and existing language allows for revaccination in those who were previously vaccinated with PCV7, but the burden of the decision to revaccinate was put on individual practitioners who rarely employed this approach.
The new wording, upon CDC approval of the committee's recommendation, will advise against routine use of PPV23 in those aged 24-59 months who were previously vaccinated with PCV7, because the current consensus is that anticipated benefits of revaccination do not outweigh potential risks. The change however, will, allow for consideration of revaccination in special situations--namely in areas in which public health authorities deem the risk for invasive pneumococcal disease is increased.
BY SHARON WORCESTER
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|Title Annotation:||Infectious Diseases|
|Date:||Nov 1, 2008|
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