OAKLAND, Calif. -- Kaiser Permanente researchers presented the results of four years' study of Prevnar, a pneumococcal vaccine effective against seven types of pneumococcal disease, at the Society for Pediatric Research conference in San Francisco last week.
Drs. Henry Shinefield and Steve Black followed Kaiser Permanente patients
from before children received the vaccine in 2000 up to March 2004.
Their data show that even unvaccinated adults and older children are
experiencing lower rates of pneumococcal disease since the vaccine's
introduction. Reduction of invasive pneumococcal disease was 52 percent in
children aged five to 19; 46 percent in people aged 20 to 39; 23 percent in
those 40 to 59; and 32 percent for adults 60 and over.
"We're excited by these findings," says Shinefield. "Truly, this is
an effect we hadn't expected -- that the vaccine would reduce the rate of
disease even in people who hadn't gotten it. It's clear that vaccinating
children diminishes the circulation of the pneumococcus in the environment,
prevents serious bacterial disease in infants and toddlers, and protects the
rest of the population as well."
The study also found that since the vaccine's introduction
penicillin-resistant pneumococcal infection has dropped from a high of 15
percent of all cases in 2000 to 5 percent in 2003.
"The decrease in penicillin resistance is related to the decrease in the
community of the seven penicillin-resistant pneumococcal types present in the
vaccine," says Shinefield.
Pneumococcus can cause pneumonia, meningitis and bacteremia -- an
infection of the bloodstream -- in children and adults. The fatality rate of
these diseases can go as high as 50 percent among adults. Immuno-compromised
adults and smokers carry higher risks of contracting the diseases.
In Kaiser Permanente's study, funded by the manufacturers of the vaccine,
Wyeth Inc., 37,868 children were vaccinated at two, four and six months, with
a booster at 12 to 15 months. The randomized controlled trial, completed in
1999, looked at incidences of invasive pneumococcal disease, and at otitis
media and pneumonia. The current report highlights the striking reduction of invasive pneumococcal disease in approximately 150,000 vaccinated and unvaccinated children under 5 years of age, as well the effects of the vaccine on the entire Kaiser Permanente Northern California population of more than 3 million.
Source: Kaiser Permanente