VAIL, COLO. - American medicine emphatically surpassed the Healthy People 2010 goal for reduction of invasive Streptococcus pneumoniae infections well ahead of schedule in both of the highest-risk target groups: children under age 5 years and seniors. And the tougher Healthy People 2020 objectives are already well within striking distance.
"We get an A+ on this," Dr. Mary P. Glodé commented at the annual pediatric infectious diseases conference sponsored by Children’s Hospital Colorado.
CDC/Dr. Mike Miller
Streptococcus pneumoniae infections particularly among children under 5 and seniors in the U.S. have been drastically reduced, surpassing the goals of the Healthy People 2010 initiative.
The Healthy People 2010 objective was to reduce the incidence of invasive S. pneumoniae infections to 46 cases per 100,000 among children under age 5 years and to 42 per 100,000 persons age 65 or older. The actual 2010 rates were 19 and 36 per 100,000, respectively.
Between 1999 and 2010, the annual rate of invasive pneumococcal disease in children younger age 5 plummeted by 86% as a consequence of the licensure in 2000 of the pneumococcal conjugate vaccine 7 (PCV 7) vaccine.
Most impressively, the rate also fell by 50% during that period among seniors, even though they didn’t receive the vaccine. This is ascribed to herd immunity. The presumed mechanism is that once immunized, young children were far less likely to become colonized by virulent pneumococcal serotypes, with resultant diminished opportunity for transmission of the pathogens to older children and adults, explained Dr. Glodé, professor of pediatrics and head of the section of pediatric infectious disease at the University of Colorado, Denver, and Children’s Hospital Colorado.
The Healthy People 2020 goal is to further reduce the incidence of invasive pneumococcal infections in children under age 5 from the 2010 rate of 19 down to 12 per 100,000, and in seniors from the 2010 figure of 36 per 100,000 to 31 per 100,000.
The expectation is that the target in children will be handily reached, and early on, as a consequence of the spring 2010 recommendation by the American Academy of Pediatrics and the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices (ACIP) that all children aged 2-59 months be routinely vaccinated with the PCV 13 vaccine, which contains the PCV 7 serotypes plus six others causing invasive disease. Early unpublished CDC data suggest there has already been some decline in disease in children as a result of the added serotypes included in PCV 13, especially in cases involving serotypes 19A and 7F, according to Dr. Glodé.
The difficult unanswered question concerns the best way to get the nation’s seniors to the Healthy People 2020 target. The rate of invasive pneumococcal disease is higher in persons aged 65 and older than in any other age group, as is the associated mortality. Indeed, of an estimated 44,000 cases of invasive pneumococcal disease in the United States during 2009, 37,000 were in adults, including 15,000 cases in individuals age 65 or more.
Late last year the Food and Drug Administration licensed the PCV 13 vaccine for use in people aged 50 and up. But that doesn’t necessarily mean it will see widespread use. There has been no official recommendation from the ACIP that the vaccine be routinely used in this population. The expert panel has noted that to date there are no data showing that the PCV 13 vaccine is effective in preventing pneumococcal pneumonia in adults, although a Dutch trial in 85,000 people over age 65 is underway.
The committee also noted that one-quarter of all cases of invasive pneumococcal disease in seniors are caused by 11 serotypes in the PPSV 23 vaccine that are not included in the PCV 13 vaccine, which further complicates the situation. The PPSV 23 vaccine has been approved since 1983 and is recommended for use in all adults over age 65 and in younger adults with certain underlying medical conditions, including diabetes and chronic lung disease.
Also, if the serotypes contained in the PCV 13 vaccine are going to largely go away in the senior population as a consequence of universal pediatric immunization, which could happen based upon the earlier herd immunity experience noted with the PCV 7 vaccine, then it may not be reasonable to give PCV 13 to all older adults, Dr. Glodé noted.
She reported serving on the data safety monitoring board for trials of an unrelated Pfizer vaccine.