Pharmacotherapy Newsletter

Volume 1, Issue 31, 08/17/2009

Question

Why do pediatric patients need their pneumococcal vaccination to be conjugated (Prevnar®) whereas adults can receive non-conjugated pneumococcal vaccine (Pneumovax®)?

Answer

It is well known that Streptococcus pneumoniae is one of the main causes of serious infections children and adults worldwide.(1,2)  Young children (less than 2 years of age) are at greatest risk, with S. pneumoniae being the most frequent cause of bacterial pneumonia, bacteremia, sinusitis, and acute otitis media.(1)  Fortunately, the risks and complications from S. pneumoniae infections have decreased with the approval and routine administration of the pneumococcal 7-valent conjugate vaccine (Prevnar®) for children less than 2 years of age and the pneumococcal vaccine polyvalent (Pneumovax® 23) in patients ³ 2 years of age with certain chronic conditions or in special environments as well as patients ³ 50 years of age.(1-4)    The different recommendations based on the age of the patient has to do with the ability of the patient to generate a protective, long term immune response.  It is evident from the names of the products that the Prevnar® formulation given to children less than 2 years of age is a conjugated vaccine, whereas the Pneumovax® 23 formulation for older patients is not conjugated.  In order to fully appreciate the answer to question for this issue, a short review of key concepts related to the development of immunity is provide below. 

What does it mean that a vaccine is conjugated?
A conjugate vaccine contains the antigens against which immunity is desired that are linked to highly... 

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