Effect of Pneumococcal Conjugate Vaccine on Pneumococcal Meningitis

Effect of Pneumococcal Conjugate Vaccine on Pneumococcal Meningitis  

ABSTRACT

Background Invasive pneumococcal disease declined among children and adults after the introduction of the pediatric heptavalent pneumococcal conjugate vaccine (PCV7) in 2000, but its effect on pneumococcal meningitis is unclear. Methods We examined trends in pneumococcal meningitis from 1998 through 2005 using active, population-based surveillance data from eight sites in the United States. Isolates were grouped into PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F), PCV7-related serotypes (6A, 9A, 9L, 9N, 18A, 18B, 18F, 19B, 19C, 23A, and 23B), and non-PCV7 serotypes (all others). Changes in the incidence of pneumococcal meningitis were assessed against baseline values from 1998–1999.

Results We identified 1379 cases of pneumococcal meningitis. The incidence declined from 1.13 cases to 0.79 case per 100,000 persons between 1998–1999 and 2004–2005 (a 30.1% decline, P<0.001). Among persons younger than 2 years of age and those 65 years of age or older, the incidence decreased during the study period by 64.0% and 54.0%, respectively (P<0.001 for both groups). Rates of PCV7-serotype meningitis declined from 0.66 case to 0.18 case (a 73.3% decline, P<0.001) among patients of all ages. Although rates of PCV7-related–serotype disease decreased by 32.1% (P=0.08), rates of non-PCV7–serotype disease increased from 0.32 to 0.51 (an increase of 60.5%, P<0.001). The percentages of cases from non-PCV7 serotypes 19A, 22F, and 35B each increased significantly during the study period. On average, 27.8% of isolates were nonsusceptible to penicillin, but fewer isolates were nonsusceptible to chloramphenicol (5.7%), meropenem (16.6%), and cefotaxime (11.8%). The proportion of penicillin-nonsusceptible isolates decreased between 1998 and 2003 (from 32.0% to 19.4%, P=0.01) but increased between 2003 and 2005 (from 19.4% to 30.1%, P=0.03).

Conclusions Rates of pneumococcal meningitis have decreased among children and adults since PCV7 was introduced. Although the overall effect of the vaccine remains substantial, a recent increase in meningitis caused by non-PCV7 serotypes, including strains nonsusceptible to antibiotics, is a concern.

 

NEJM:

Volume 360:244-256

 

January 15, 2009

Also:

Pediatric Vaccine Effectively Prevents Pneumococcal Meningitis, Study Suggests

ScienceDaily (Jan. 16, 2009) — A standard pediatric vaccine used to prevent several common types of life-threatening infections also effectively reduced the rates of another disease, pneumococcal meningitis, in children and adults, according to a multi-center study led by the University of Pittsburgh School of Medicine. The study, published in the Jan. 15 issue of the New England Journal of Medicine and based on a detailed review of pneumococcal meningitis cases, also noted an increase in strains of pneumococcal meningitis not covered by the vaccine and those resistant to antibiotics.

An often deadly disease, pneumococcal meningitis is an infection in the brain and spinal cord membranes caused by the pneumococcus – a bacterium that also causes pneumonia and other serious infections. The highest rates of pneumococcal infections occur in very young children. There are approximately 2,700 cases of pneumococcal meningitis in the U.S. every year.

After reviewing 1,379 cases of pneumococcal meningitis from 1998 through 2005, study authors found rates of the disease decreased in children and adults after the introduction of pediatric pneumococcal conjugate vaccine (PCV7) in 2000. PCV7 protects against seven of the most common pneumococcal types, which account for over 80 percent of pneumococcal disease in young children. PCV7 is not administered to adults.

According to the study, incidence rates for pneumococcal meningitis in all age groups declined 30.1 percent from 1998-1999 to 2004-2005. After PCV7 was made available, the incidence of meningitis decreased by 64 percent in children and by 54 percent in older adults.

“When you immunize children, they are much less likely to carry pneumococcal strains covered by the vaccine in the back of the throat,” explained Lee Harrison, M.D., senior author of the study and professor of medicine, University of Pittsburgh School of Medicine. “When vaccinated children don’t carry these virulent strains, they don’t end up transmitting them to other children, their parents and grandparents.” Prior to the study, conflicting data existed on the vaccine’s effect on the incidence of meningitis in adults, he said.

The authors also observed that non-PCV7 strains increased by 60.5 percent from the 1998-1999 period to 2004-2005, and the percentage of strains that were not sensitive to penicillin, which initially declined, increased from 19.4 percent in 2003 to 30.1 percent in 2005.

“PCV7 has been highly successful in preventing pneumococcal meningitis, but it remains a very serious and deadly disease,” said Dr. Harrison. “Of the patients in our study, 8 percent of children and 22 percent of adults died. These findings indicate the need to continue to explore new methods of prevention with a special emphasis on strains that are not covered by PCV7 and strains that are drug resistant. Next-generation vaccines are in development and patients and physicians need to avoid unnecessary use of antibiotics.”

In addition to Dr. Harrison, who conducted this study in collaboration with the Johns Hopkins Bloomberg School of Public Health, co-authors of the study include first author Heather Hsu, M.P.H. and Kathleen Shutt, both at the University of Pittsburgh; Matthew Moore, M.D., M.P.H., Bernard Beall, Ph.D., and Cynthia Whitney, M.D., M.P.H., Centers for Disease Control and Prevention; Nancy Bennett, M.D., University of Rochester; Allen Craig, M.D., Tennessee Department of Health; Monica Farley, M.D., Emory University; James Jorgensen, Ph.D., University of Texas Health Sciences Center; Catherine Lexau, Ph.D., M.P.H., Minnesota Department of Health; Susan Petit, M.P.H., Connecticut Department of Health; Arthur Reingold, M.D., University of California Berkeley; William Schaffner, M.D., Vanderbilt University School of Medicine; and Ann Thomas, M.D., Oregon State Public Health Division.

The study was funded by the Centers for Disease Control and Prevention (CDC) and the National Institute of Allergy and Infectious Diseases.

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