Ask the Experts - Should the Conjugate Pneumococcal Vaccine Be Offered...
Ask the Experts - Should the Conjugate Pneumococcal Vaccine Be Offered...
Any intervention that might result in a reduction of pneumococcal disease would obviously benefit older children and adults, as well as the age groups at highest risk -- ie, children younger than age 2 years and adults older than age 65. Does the recently approved conjugate pneumococcal vaccine therefore represent a vaccine that should be given to everyone, or would such a recommendation represent an inappropriate "leap of faith" at this point?
Neylon S. Pilkington, MD
There is some evidence that the previously available pneumococcal polysaccharide vaccine (PPV) has benefited children older than 5 years of age. The observed reduction in invasive infection among older vaccinated children with sickle cell disease offers the best support of clinical efficacy in the pediatric population. Although there have been no controlled clinical trials, children with cystic fibrosis usually receive pneumococcal vaccine, and the incidence of disease in this group is reported to be relatively low. On the other hand, PPV was not effective for the prevention of acute otitis media or sinusitis in children 2 to 7 years of age.
Several clinical trials have been conducted evaluating the protection afforded by PPV against pneumonia and pneumococcal bacteremia in adults. In addition, multiple case-controlled and serotype prevalence studies have provided evidence for pneumococcal vaccine effectiveness against invasive disease. These studies led to recommendations published by the Centers for Disease Control and Prevention (CDC) and the Advisory Committee on Immunization Practices. Most pneumococcal disease in the United States occurs in elderly adults or in persons with chronic medical conditions (both children and adults). Vaccine efficacy for nonbacteremic pneumonia was not demonstrated for these populations in 2 postlicensure trials conducted in the United States. However, these studies may have lacked sufficient statistical power to detect a difference in the incidence of laboratory-confirmed, nonbacteremic, pneumococcal pneumonia between the vaccinated and nonvaccinated study groups. A meta-analysis evaluating pneumococcal vaccine efficacy was conducted by combining the results of 9 randomized, controlled trials; a protective effect for nonbacteremic pneumonia was not demonstrated among persons in high-risk groups. Importantly, the ability to evaluate vaccine efficacy in all of the studies is limited because of the lack of specific and sensitive diagnostic tests for nonbacteremic pneumococcal pneumonia.
So where does that leave us with respect to medical decisions about how to use the new conjugate pneumococcal vaccine in children older than 5 years of age? The most recent guidelines for the conjugate pneumococcal vaccine are for those under 5 years of age. Either we believe in aggressive preventive interventions or we don't. Do we require extensive unequivocal results from vaccine efficacy trials before making a recommendation? These questions must be answered by the individual clinician. If you have had the experience of managing fatal cases of invasive pneumococcal disease in otherwise normal children older than 5 years, as I have, your decision might also be to provide this new vaccine to all of the older children and adults for whom you are responsible.
Any intervention that might result in a reduction of pneumococcal disease would obviously benefit older children and adults, as well as the age groups at highest risk -- ie, children younger than age 2 years and adults older than age 65. Does the recently approved conjugate pneumococcal vaccine therefore represent a vaccine that should be given to everyone, or would such a recommendation represent an inappropriate "leap of faith" at this point?
Neylon S. Pilkington, MD
There is some evidence that the previously available pneumococcal polysaccharide vaccine (PPV) has benefited children older than 5 years of age. The observed reduction in invasive infection among older vaccinated children with sickle cell disease offers the best support of clinical efficacy in the pediatric population. Although there have been no controlled clinical trials, children with cystic fibrosis usually receive pneumococcal vaccine, and the incidence of disease in this group is reported to be relatively low. On the other hand, PPV was not effective for the prevention of acute otitis media or sinusitis in children 2 to 7 years of age.
Several clinical trials have been conducted evaluating the protection afforded by PPV against pneumonia and pneumococcal bacteremia in adults. In addition, multiple case-controlled and serotype prevalence studies have provided evidence for pneumococcal vaccine effectiveness against invasive disease. These studies led to recommendations published by the Centers for Disease Control and Prevention (CDC) and the Advisory Committee on Immunization Practices. Most pneumococcal disease in the United States occurs in elderly adults or in persons with chronic medical conditions (both children and adults). Vaccine efficacy for nonbacteremic pneumonia was not demonstrated for these populations in 2 postlicensure trials conducted in the United States. However, these studies may have lacked sufficient statistical power to detect a difference in the incidence of laboratory-confirmed, nonbacteremic, pneumococcal pneumonia between the vaccinated and nonvaccinated study groups. A meta-analysis evaluating pneumococcal vaccine efficacy was conducted by combining the results of 9 randomized, controlled trials; a protective effect for nonbacteremic pneumonia was not demonstrated among persons in high-risk groups. Importantly, the ability to evaluate vaccine efficacy in all of the studies is limited because of the lack of specific and sensitive diagnostic tests for nonbacteremic pneumococcal pneumonia.
So where does that leave us with respect to medical decisions about how to use the new conjugate pneumococcal vaccine in children older than 5 years of age? The most recent guidelines for the conjugate pneumococcal vaccine are for those under 5 years of age. Either we believe in aggressive preventive interventions or we don't. Do we require extensive unequivocal results from vaccine efficacy trials before making a recommendation? These questions must be answered by the individual clinician. If you have had the experience of managing fatal cases of invasive pneumococcal disease in otherwise normal children older than 5 years, as I have, your decision might also be to provide this new vaccine to all of the older children and adults for whom you are responsible.
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