Meningitis Vaccine Leads to Greater Reduction in Ear Infections

Approximately 80% of children three years of age and younger are affected by otitis media, with treatment costs estimated at more than $5 billion per year. The affliction is painful for children and frustrating and costly for parents. The introduction of the heptavalent pneumococcal conjugate vaccine in 2000 caused a reduction in the number of ear infections caused by Streptococcus pneumoniae bacteria. New research shows that the effect of this vaccine on reduction of serious pediatric ear infections and the need for insertion of ventilating ear tubes may be even greater than anticipated.

The Heptavalent Pneumococcal Conjugate Vaccine

S. pneumoniae is the leading cause of bacterial meningitis in the United States. It also causes other serious problems such as blood infections, pneumonia, and ear infections. Up to one-third of ear infections are believed to be caused by the S. pneumoniae bacteria.

The heptavalent pneumococcal conjugate vaccine (PCV7), which was licensed in the United States in February 2000, is marketed by Wyeth Pharmaceuticals as Prevnar. In June 2000, the Centers for Disease Control and Prevention (CDC) recommended that all children aged 23 months and younger receive the PCV7 vaccine. That same month, the American Academy of Pediatrics (AAP) issued its own recommendation that mimicked that of the CDC. Both agencies further recommended that children between 24 and 59 months of age who were determined to be at especially high risk should also be vaccinated. This includes children who have illnesses or take medications that affect the immune system or who have chronic heart or lung disease.

The vaccine is administered in four doses, given at 2, 4, 6, and 12 to 15 months of age, and can be incorporated into the scheduled administration of other childhood vaccines. Children who are allergic to any component of Prevnar should not receive the vaccine, and any child who is moderately or severely ill should wait until he or she has recovered before receiving the vaccine. A full four-dose regimen of Prevnar is 97% effective in preventing the seven strains of the pneumococcus bacterium included in the vaccine. Health officials believe that even a reduced regimen of the vaccine will provide some benefit.

According to Peter Paradiso, PhD, Vice-President of Scientific Affairs for Wyeth Vaccines, the prelicensure studies of the Prevnar vaccine conducted in California and Finland showed 25% to 40% reductions in ear tube placement, regardless of cause. He stated in a telephone interview, It was clear in children who had serious ear infections and recurrent ear infections leading to ear tubes, that there was significant reduction as a result of the vaccination.

Studies have shown no serious reactions associated with this vaccine to date. Mild reactions can include:

• Redness, tenderness, or swelling at the administration site.
• Fever.
• Fussiness, drowsiness, or loss of appetite.

The Pediatrics Study

A study published earlier this year in Pediatrics, which was funded in part by the Centers for Disease Control and Prevention’s New Vaccine Surveillance Network, was the first to document the long-term effects of the vaccine on otitis media.1 The objective of the study was to estimate the effect of routine childhood immunization with heptavalent pneumococcal conjugate vaccine on frequent otitis media (three episodes in six months or four episodes in one year) and pressure-equalizing tube (PET) insertions.

The study included all children enrolled at birth in TennCare, Tennessee’s managed care program that includes the Medicaid population and other low-income children, and all children enrolled at birth in three selected commercial insurance managed care organizations in upstate New York. The study population included children born between February 1998 and May 2003. The participants were broken into four birth cohorts: those born between July 1 and June 30, 1998-1999, 1999-2000, 2000-2001, and 2001-2002. The participants were followed until they reached five years of age.

Frequency of otitis media decreased progressively for all birth cohorts in the New York group, with percentages of decrease ranging from 16% to 30%. Decline in PET insertion in the New York participants ranged from 13% to 23%.

The Tennessee group showed a 16% to 17% decrease in otitis media through the 2000-2001 cohort, and then reflected an increase in the 2001-2002 group. However, the frequency of otitis media in 2001-2002 cohort remained lower than the 1998-1999 group. The results reflected a 3% decrease in frequency of otitis media in the Tennessee group over the life of the study. After showing a 12% to 16% decrease in earlier cohorts, the number of PET procedures in the 2001-2002 cohort in Tennessee was comparable to that of the 1998-1999 group.

Katherine Poehling, MD, Associate Professor of Pediatrics at Brenner Children’s Hospital at Wake Forest University in Winston-Salem, NC, primary author of the study, pointed out that the two groups included in the study were intensely different populations. She stated, In New York private insurance, we saw a progressive increase in benefit. In Tennessee, we saw a different pattern. Initially, there was a progressive increase, and then in the last year it went back nearly to baseline. What that means is unclear at this time.

J. Pekka Nuorti, MD, Medical Epidemiologist at the Centers for Disease Control and Prevention and co-author of the study, opined that the different outcomes in the Tennessee group versus the New York group may reflect differences in vaccination coverage or prevalence of risk factors for pneumococcal disease in each group.

Due to discrepancies in the reporting and diagnosing by health care professionals, the authors were not able to compare the results for individual children who received the PCV7 vaccine with results for those who did not. However, there has been an overall increase nationally between 1998 and 2002 in the number of children under the age of two who received the vaccine. It is also believed that unvaccinated and undervaccinated children receive some indirect benefit by decreased carriage of the S. pneumoniae bacteria by children who have been fully vaccinated.

The study concluded that following the introduction of the heptavalent pneumococcal conjugate vaccine in 2000 children were less likely to develop frequent otitis media or have PET insertions. The authors cautioned that further study and monitoring should be conducted to determine whether the findings will continue or whether they will wane.

Dr. Nuorti summarized the importance of this study: These are the first data to show a longitudinal look at what happens when this vaccine is used in a population. It emphasizes that some of the important effects of a vaccine can only be seen through routine wide-scale use.

Additional Sources

1. Pneumococcal Conjugate Vaccine: What You Need to Know. Centers for Disease Control & Prevention. Available at www.cdc.gov/Nip/publications/VIX/vis-PneumoConjugate.pdf . (Accessed April 29, 2007.)
2. Preventing Pneumococcal Disease Among Infants and Young Children: Recommendations of the Advisory Committee on Immunization Practices (ACIP). Centers for Disease Control & Prevention. Available at www.cdc.gov/mmwr/preview/mmwrhtml/rr4909a1.htm . (Accessed April 29, 2007.)
3. Prevnar Web site: http://prevnar.com/pro_index.asp. (Accessed April 11, 2007.)

Reference

1. Poehling KA, Szilagyi PG, Grijalva CG, et al. Reduction of frequent otitis media and pressure-equalizing tube insertions in children after introduction of pneumococcal conjugate vaccine. Pediatrics 2007;119:707-15.

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©2007 The Triological Society