Pneumococcal vaccine results in widespread reduction of serious disease
Researchers from the Johns Hopkins School of Public Health and the U.S. Centers for Disease Control and Prevention found that PCV7, a vaccine that covers seven strains of pneumococcal bacteria, decreased the rate of serious bacterial infections known as invasive pneumococcal disease. The vaccine also resulted in small increases in IPD caused by Streptococcus pneumoniae strains not covered by the vaccine.
"The most important public health implication of our analysis was that decreases in overall IPD rates in children - the group targeted for PCV7 vaccination - occurred quickly and were sustained after vaccine introduction despite increases in (non-vaccine serotype) rates," the authors said.
The authors combined IPD surveillance information from multiple countries to estimate changes in IPD rates before and after PCV7 introduction. The rate of IPD caused by vaccine serotypes decreased every year over the seven years studied, though the rate of IPD caused by non-vaccine serotypes increased each year.
The study has implications for the surveillance of newer pneumococcal conjugate vaccines like PCV10 and PCV13, which cover additional serotypes.
"Optimizing surveillance data that allows for valid interpretations of the vaccine effect on disease is essential for sound policy decisions," the authors said.
The authors added that the findings contain limitations. PCV7 is no longer made and extrapolation of the results to PCV10 and PCV13 formulations must be done cautiously. The surveillance data also came from high-income countries and may not be generalizable to low-income countries.