Rate of Bacterial Infections Drops among Infants; Vaccination of Older Children Linked to Findings
Byline: Joyce Howard Price, THE WASHINGTON TIMES
Infants too young to receive a vaccination against pneumonia, meningitis and other potentially deadly bacterial infections have experienced a drop in the rate of those diseases, possibly as a result of older children having been immunized.
The information is contained in a report by Vanderbilt University researchers, published in the current issue of Journal of the American Medical Association.
The study found a 42 percent decline in rates of invasive pneumococcal disease (IPD) caused by the bacteria, streptococcus pneumoniae, among children under 2 months old since a vaccine went on the market in February 2000.
Researchers say similar decreases in rates of IPD have been reported for children older than 5 years and adults who are not specific targets of recommendations for immunization with the so-called heptavalent pneumococcal conjugate vaccine, or PCV7. In the United States, PCV7 is recommended for all children between the ages of 2 months and 23 months. Younger babies and older youngsters are not receiving it.
Dr. Katherine A. Poehling and colleagues at the Vanderbilt University School of Medicine in Nashville, Tenn., said their report is the first to indicate that "neonates (infants up to 30 days old) and other infants too young to receive PCV7 are benefiting from herd immunity." Herd immunity, they said, "occurs when vaccinated persons in a population indirectly protect unvaccinated ones by impeding the spread of an infectious agent. …