Fooling with Mother Nature

It has been reported that Prevnar, the vaccine for seven strains of pneumococcal bacteria, has been behind the decreased incidence of pneumonia and ear infections in children. But when bacteria or viruses are eliminated, more aggressive microbes evolve. One particular strain of strep that is emerging, serotype 19A, is causing more invasive disease than the others have in the past. The new bug is called "replacement disease."

It happened with Hemophilus influenza b, the organism that used to be the most common cause of ear infections in kids. That microbe was eliminated when the HiB vaccine was introduced in 1991. In its place, aggressive strep bacteria became the most common causes of ear infections and pneumonia. Since the introduction of Prevnar in 2000, the most common types of strep in circulation were eliminated. The replacement disease--in addition to serotype 19A--is a highly aggressive bug for serious meningitis, Neisseria meningitidis. Now what is recommended? A new vaccine for meningitis (Menactra), that can result in paralysis called Guillian barre.

The overall "effectiveness" of the vaccines will continue to erode. You can't fool with Mother Nature for very long.