Pneumonia Vaccine Brings New Challenge
Vaccine's Success May Lead to Rise in Pneumonia Caused by Other Bacteria
WebMD News Archive
April 24, 2007 -- The success of the pneumonia vaccine in children may allow a rise in kids' pneumonia caused by germs not targeted by the vaccine.
That's according to researchers including the CDC's Rosalyn Singleton, MD, MPH.
In The Journal of the American Medical Association, Singleton's team recommends monitoring children's pneumonia and updating pneumococcal disease vaccines as needed.
Journal editorialists agree. They call the children's pneumococcal vaccine "a towering success" but add that "the target is moving."
Pneumococcal Disease Vaccine
Pneumococcal diseases include life-threatening pneumonia and meningitis.
The CDC recommends the pneumococcal conjugate vaccine PCV7, given in four doses, for all children who are less than 2 years old. Children aged 2-5 can get catch-up doses of the vaccine.
The vaccine targets seven strains of Streptococcus pneumoniae bacteria. Those strains are the leading causes of pneumococcal disease, but other bacteria can also cause pneumonia.
Pneumococcal Vaccine Study
Singleton and colleagues studied Alaska Native children, who had high rates of pneumococcal disease before the vaccine.
The researchers focused on children who were 19-35 months old between Sept. 30, 2003, and Sept. 30, 2006. The PCV7 vaccine was introduced to children's routine immunization schedule in Alaska on Jan. 1, 2001.
As the vaccine became widely used, reported pneumococcal disease cases caused by vaccine-targeted bacteria plummeted 67% in Alaska Native children younger than 2 years old.
But at the same time, reported pneumococcal disease cases caused by other nonvaccine strains of bacteria soared 82% in Alaska Native children less than 2 years old.
The study also shows that since 2004, the children had a 96% drop in reported pneumococcal disease cases caused by vaccine-targeted bacteria. But there was also a 140% rise in children's pneumococcal disease cases caused by nonvaccine strains during the same time period.
The vaccine has been a "dramatic success," write Singleton and colleagues. But they note that other strains of the bacteria not targeted by the vaccine may be stepping up to fill the void.
It's not clear if the study's findings apply to children nationwide. Singleton's team calls for ongoing monitoring of pneumococcal disease and the development of expanded pneumococcal vaccines.
Meanwhile, the PCV7 vaccine is still effective against the bacteria it targets, note Timothy Peters, MD, and Katherine Poehling, MD, MPH, in their editorial.
Peters and Poehling work at Brenner Children's Hospital at Wake Forest University School of Medicine in Winston-Salem, N.C.