The apparent disparity between a 57% pneumococcal serotype specific efficacy and a 7% decrease of OM episodes is explained by the fact that OM is caused by numerous bacterial and viral pathogens. Thus, it is important to distinguish between the effect on a population versus the effect on an individual. As a result, the impact of Prevnar on OM for any one child would be expected to be limited. However, because OM is such a common disease, a small reduction in disease at a population level would have clinically significant impact on our healthcare system.
Frank J. Malinoski, MD, PhD
Dagna S. Laufer, MD
Clinical Affairs
Wyeth-Ayerst Pharmaceuticals
Philadelphia, Pennsylvania
- Kaufmann M, Dobie S. Does a multivalent pneumcoccal vaccine given to infants prevent otitis media? J Fam Pract 2001; 50:395.
- Eskola J, Kilpi T, Palmu A, et al. Efficacy of a pneumoccocal conjugate vaccine against acute otitis media. N Engl J Med 2001; 344:403-09.
- Black S, Shinefield H, Fireman B, et al. Efficacy, safety, and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Pediatr Infect Dis J 2000; 19:187-95.
The preceding letter was referred to Drs Kaufmann and Dobie who responded as follows:
Our review evaluated the article by Eskola and colleagues,1 “Efficacy of a pneumococcal vaccine against otitis media,” which described the results of the Finnish Otitis Media Vaccine Trial. Although the study showed that the pneumococcal CRM197 conjugate vaccine reduced episodes of pneumococcal acute otitis media, it did not show a statistically significant reduction in episodes of acute otitis media from all causes. It is possible that the trial failed to show this because it was not powered to evaluate this endpoint, but it is inappropriate to draw any clinical conclusions from statistically insignificant results or to compare these results to the results found in other studies. We stand by our assertion that this study alone does not provide sufficient evidence to recommend vaccination with a pneumococcal conjugate vaccine for the prevention of otitis media.
It is possible and hopeful that routine childhood immunization with the pneumococcal vaccine could reduce the incidence of acute otitis media as well as the incidence of severe or invasive pneumococcal disease. We thank the letter writers for highlighting the results of the large Northern California Kaiser Permanente trial that used computerized diagnosis and visit data for several different outcome measures.2 Although only 58% of the 37,868 infants enrolled in the trial received a full 4-dose series of immunizations, intention-to-treat analysis showed a reduction in clinical otitis media of 6.4% (95% confidence interval, 3.9%-8.7%). Although the risk reduction from immunization may be small for a given child, the impact of the pneumococcal vaccine on the population disease burden of otitis media could be considerable.
Mary Kauffman, MD, MPH
Sharon Dobie, MCP, MD
Family Medical Center Seattle, Washingon
- Eskola J, Kilpi T, Palmu A, et al. Efficacy of a pneumococcal conjugate vaccine against acute otitis media. N Engl J Med 2001; 344:403-09.
- Black S, Shinefield H, Fireman B, et al. Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Pediatr Infect Dis J 2000; 19:187-95.