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May 1, 2001

Pneumococcal Vaccine Extremely Effective for High-Risk Native American Communities

Vaccine Also Helps Prevent Children From Becoming Carriers of the Bacteria

Two separate studies conducted by the Johns Hopkins School of Public Health concluded that the new conjugated pneumococcal vaccine, which is sold under the brand name Prevnar, effectively protects Native American children from seven types of Streptococcus pneumoniae bacteria and helps protect vaccinated children from becoming carriers of those types. Pneumococcal infections can cause a number of serious illnesses including deadly bacterial meningitis.

The studies are the first to examine the vaccine's effectiveness in a high-risk community and the first to show that Prevnar-vaccinated children are less likely to carry the targeted types of pneumococcal bacteria. The findings of both studies were presented on May 1, 2001, at the Pediatric Academic Societies Conference in Baltimore, Md.

"Navajo and Apache Indian children are five times more likely to have serious pneumococcal infections compared to other children in the United States. Some vaccines do not work as well among Native American people, but our studies indicate that this new pneumococcal vaccine is extremely effective and should help prevent infections," says Katherine O'Brien, MD, who is lead author of both studies and a research professor with the Center for American Indian Health at the Johns Hopkins School of Public Health.

For the first study, researchers selected more than 8,000 infants and toddlers living in 38 Navajo and White Mountain Apache Indian communities between 1997 and 1999. All of the children were between six weeks and two years of age. Each of the 38 communities was randomly assigned to receive either the pneumococcal vaccine or a control vaccine.

"We found that the vaccine was nearly 83 percent effective at preventing serious pneumococcal infections among infants who received at least one dose of the vaccine prior to seven months of age. The vaccine was 86 percent efficacious among all infants who received at least one dose of the vaccine prior to two years of age. These results may also be good news for other groups who are also at increased risk for pneumococcal disease, such as children in daycare and African-American children," explains Dr. O'Brien.

For the second study, researchers randomly selected 577 children from the first study and examined their noses for the presence of pneumococcal bacteria. The pneumococcal vaccine did not impact the proportion of children carrying pneumococcal bacteria of any type. Overall pneumococcal bacteria were found in the noses of 62 percent of the children vaccinated with the pneumococcal vaccine and in 64 percent of the children vaccinated with the control vaccine. However, according to the research, children who received the pneumococcal vaccine were less likely to carry the seven types of pneumococcal bacteria targeted by the vaccine compared to children who received the control vaccine.

"The finding is significant, because it shows the vaccine protects children from becoming carriers of the targeted bacteria. This could help reduce the spread of the bacteria to children and adults in the community who have not been vaccinated," explains Dr. O'Brien.

L. Moulton, R. Reid, G. Kumar, J. Oski, L. Brown, R. Weatherholtz, M. Santosham, J. Hackell, R. Kohberger, I. Chang, and G. Siber contributed to the work of the first study. M.A. Bronsdon, G.M. Carlone, R.R. Facklam, B. Schwartz, R.R. Reid, and M. Santosham contributed to the work of the second study.

Funding for the study was provided by Wyeth Lederle Vaccines, the National Institutes of Health, USAID, and the Centers for Disease Control and Prevention.

Public Affairs Media Contacts:Tim Parsons @ 410.955.6878 or paffairs@jhsph.edu