Vaccine Cuts Pneumococcal Disease
Vaccine-Targeted Infections Down, Other Strains Up, Study Shows
April 5, 2006 -- A vaccine launched in 2000 has cut U.S. cases of invasive pneumococcal disease.
Invasive pneumococcal disease includes pneumonia and meningitis. The vaccine is among those routinely given to children. It targets seven strains of invasive pneumococci bacteria; five of those strains resist treatment with antibiotics.
After the vaccine's introduction, U.S. cases of invasive pneumococcal disease dropped for strains covered by the vaccine. The CDC's Moe Kyaw, MD, PhD, and colleagues report that news in The New England Journal of Medicine.
However, Kyaw's team also notes a rise in cases of pneumococcal disease caused by strains not targeted by the vaccine.
Before and After
Data covered 1996-2004. That period spans the four years before and after the vaccine's introduction.
Information came from eight U.S. locations: Atlanta; Baltimore; Connecticut; parts of Tennessee; Minneapolis and St. Paul; Portland, Ore.; San Francisco County, Calif.; and Rochester, N.Y.
The study shows that from 1996 to 2004, rates of resistant invasive pneumococcal disease peaked in 1999. Rates of those resistant infections covered by the vaccine fell 87% from 1999 to 2004, Kyaw's team writes.
The drop in infection among vaccine recipients was "remarkable," writes editorialist Daniel Musher, MD. Musher works in Houston at Baylor College of Medicine and the Michael E. DeBakey Veterans Affairs Medical Center. He wasn't involved in Kyaw's study.
Cases Down in Kids, Elders
The vaccine is recommended for all kids younger than 2 years old and for 2- to 4-year-olds who have certain high-risk health conditions.
However, infections caused by strains covered by the vaccine fell in a wider range of age groups after the vaccine's introduction.
Among kids less than 2 years old, cases caused by penicillin-resistant strains fell 81% from the 1999 peak to 2004. Those cases were also nearly halved in adults aged 65 and older during that time.
Seniors might have been helped by greater use of their own pneumococcal vaccine, which is different from the ones kids take. Vaccinating kids may also mean less transmission to adults, Kyaw and colleagues note.
Beyond the Vaccine
The kids' vaccine doesn't cover all strains of pneumococcal disease. Kyaw's team saw a rise in cases caused by strains not covered by the vaccine.
However, "the magnitude of this effect was relatively small," the researchers write. One of those strains, called serotype 19A, resists antibiotics, which is "worrisome," Musher writes.
Musher warns parents not to count on their unvaccinated children being protected by the drop in invasive pneumococcal disease. Cases may have fallen nationwide, but invasive pneumococcal disease hasn't gone away.