FRIDAY, April 6, 2007 (HealthDay News) -- Vaccinating infants with the pneumococcal conjugate vaccine has resulted in a 39 percent drop in the number of children hospitalized for pneumonia in the United States, researchers report.
Since the use of the PCV7 vaccine began in 2000 there has been a dramatic decline in hospital admissions for pneumonia, especially for children younger than 2 years of age, said lead researcher Dr. Carlos Grijalva, an assistant professor of preventive medicine at Vanderbilt University School of Medicine in Nashville.
"A large number of pneumonia can be prevented with this vaccine," Grijalva said. "It was believed that the primary focus of the vaccine was on diseases such as meningitis and bacteremia, but this vaccine also has the ability to protect against more common infections like pneumonia and otitis media (ear infections)," he said.
In the study, Grijalva's team used the Nationwide Inpatient Sample -- the largest inpatient database available in the United States -- to collect statistics on hospital admissions for pneumonia among children under 2 years of age. The researchers looked at hospital admissions for pneumonia between 1997 and 1999, and from 2001 to 2004.
Reporting in the April 7 issue of The Lancet, the researchers found that rates of hospital admissions for pneumonia fell by 506 cases per 100,000 children -- a reduction of some 41,000 admissions in 2004.
In addition, Grijalva's group found a "herd immunity effect," whereby parents and others close to the vaccinated children also benefited from the vaccination by not being exposed to pneumonia.
In the United States, pneumonia and influenza are the greatest infectious causes of death, accounting for between 3 percent and 18 percent of all childhood hospital admissions, according to the study.
Grijalva noted that more than 80 percent of infants are now being vaccinated with the PCV7 vaccine. "We would like to see the levels go even higher," he said.
He also believes the U.S. experience can serve as a model for similar vaccination programs elsewhere. "The number of diseases, especially pneumonia, that can be prevented is substantial," he said.
One expert was similarly impressed with the study findings.
"This study illustrates again that the vaccine is consistently meeting its expectations in terms of its health impacts," said Orin S. Levine, an associate professor and executive director of PneumoADIP at Johns Hopkins Bloomberg School of Public Health and the author of an accompanying journal editorial. "In terms of pneumonia it's more effective than people expected," he added.
When the original calculation of the cost-effectiveness of the vaccine was done, "no one counted on all of these pneumonia cases being prevented," Levine said. "So it shows that the vaccine is more valuable than people were giving it credit for."
Moreover, Levine believes the study shows how common pneumococcal disease is and "how valuable the vaccine is for its prevention."
For more information on pneumococcal vaccine, visit the U.S. Centers for Disease Control and Prevention.