Acute Otitis Media: Influence of the PCV-7 vaccine on changes in the disease and its management

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Acute Otitis Media: Influence of the PCV-7 vaccine on changes in the disease and its management

J Fam Pract. 2005 November;54(11):961-968

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References

1. Fireman B, Black SB, Shinefield HR, et al. Impact of the pneumococcal conjugate vaccine on otitis media. Pediatr Infect Dis J. 2003;22:10-16.

2. Eskola J, Kilpi T, Palmu A, et al. Efficacy of a pneumococcal conjugate vaccine against acute otitis media. N Engl J Med. 2001;344:403-409.

3. Block SL, Harrison CH, Hedrick J, et al. Restricted use of antibiotic prophylaxis for recurrent acute otitis media in the era of penicillin non-susceptible Streptococcus pneumoniae. Int J Pediatr Otorhinolaryngol. 2001;61:47-60.

4. Advisory Committee on Immunization Practices. Preventing pneumococcal disease among infants and young children: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2000;49(RR-9):1-35.

5. American Academy of Family Physicians Subcommittee on Management of Acute Otitis Media. Diagnosis and management of acute otitis media. Pediatrics. 2004;113:1451-1465.

6. Dowell SF, Butler JC, Giebink GS, et al. Acute otitis media: management and surveillance in an era of pneumococcal resistance—a report from the Drug-resistant Streptococcus pneumoniae Therapeutic Working Group. Pediatr Infect Dis J. 1999;18:1-9.

7. Block SL. Causative pathogens, antibiotic resistance and therapeutic considerations in acute otitis media. Pediatr Infect Dis J. 1997;16:449-456.

8. Bluestone CD, Stephenson JS, Martin LM. Ten-year review of otitis media pathogens. Pediatr Infect Dis J. 1992;11(suppl 8):S7-S11.

9. Block SL, Hedrick J, Harrison CJ, et al. Community-wide vaccination with the heptavalent pneumococcal conjugate significantly alters the microbiology of acute otitis media. Pediatr Infect Dis J. 2004;23:829-833.

10. Casey JR, Pichichero ME. Changes in frequency and pathogens causing acute otitis media in 1995-2003. Pediatr Infect Dis J. 2004;23:824-828.

11. Centers for Disease Control and Prevention. Updated recommendations on the use of pneumococcal conjugate vaccine: suspension of recommendation for third and fourth dose. MMWR Morb Mortal Wkly Rep. 2004;53:177-178.

12. Centers for Disease Control and Prevention. Pneumococcal conjugate vaccine shortage resolved. MMWR Morb Mortal Wkly Rep. 2004;53:851-852.

13. Prevnar® (pneumococcal 7-valent vaccine) [prescribing information]. Philadelphia, Pa: Wyeth Pharmaceuticals. Rev. 01/04.

14. Watson W. Pneumococcal conjugate vaccines. Pediatr Infect Dis J. 2000;19:331-332.

15. Giebink GS. The prevention of pneumococcal disease in children. N Engl J Med. 2001;345:1177-1183.

16. Pelton SI, Loughlin AM, Marchand CD. Seven valent pneumococcal conjugate vaccine immunization in two Boston communities: changes in serotypes and antimicrobial susceptibility among Streptococcus pneumoniae isolates. Pediatr Infect Dis J. 2003;23:1015-1022.

17. Freed GL, Davis MM, Clark SJ. Variation in public and private supply of pneumococcal conjugate vaccine during a shortage. JAMA. 2003;289:575-578.

18. Centers for Disease Control and Prevention. Decreased availability of pneumococcal conjugate vaccine. MMWR Morb Mortal Wkly Rep. 2001;50:783-784.

19. Centers for Disease Control and Prevention. Limited supply of pneumococcal conjugate vaccine: suspension of recommendation for fourth dose. MMWR Morb Mortal Wkly Rep. 2004;53:108-109.

20. CDC National Immunization Survey. Estimated vaccination coverage with individual vaccines and selected vaccination series by 24 months of age by state and immunization action plan area US, Q3/2003-Q4/2004. Available at: http://www2a.cdc.gov/nip/coverage/nis/nis_iap.asp?fmt=v&rpt=tab09_24mo_iap_0304&qtr=Q3/2003-Q2/2004. Accessed September 20, 2005.

21. Whitney CG, Farley MM, Hadler J, et al. Decline in invasive pneumococcal disease after the introduction of protein-polysaccharide conjugate vaccine. N Engl J Med. 2003;348:1737-1746.

22. Black S, Shinefield H, Baxter R, et al. Postlicensure surveillance for pneumococcal invasive disease after use of heptavalent pneumococcal vaccine in Northern California Kaiser Permanente. Pediatr Infect Dis J. 2004;23:485-489.

23. Pichichero ME, Casey JR. Acute otitis media: Making sense of recent guidelines on antimicrobial treatment. J Fam Pract. 2005;54:313-332.

24. Block SL, Harrison CJ. Diagnosis and Management of Acute Otitis Media, 3rd ed. In press.

PCV-7 conjugate vaccine

The PCV-7 conjugate vaccine was approved for use in February 2000. It is a 7-valent pneumococcal conjugate of the capsular antigens of the S pneumoniae serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F, individually conjugated to diphtheria CRM197 protein.¹³ These serotypes have been responsible for approximately 80% of invasive pneumococcal disease in children younger than 6 years in the United States.^13,14 They also accounted for 74% of penicillin-susceptible S pneumoniae and 100% of pneumococci with high-level penicillin resistance isolated from children younger than age 6 years with invasive disease during a 1993-1994 surveillance by the Centers for Disease Control and Prevention (CDC).¹³

Mechanism of Action and Recommended Immunization Schedule

The conjugate vaccine is converted to a T-cell–dependent antigen, antibody formation is enhanced, and memory B cells are primed.¹⁴

The recommended immunization schedule was established as 3 primary doses at ages 2, 4, and 6 months and a booster dose at 12 to 15 months.¹ It is the first multivalent pneumococcal vaccine approved for use in children younger than 24 months.

An 89% reduction in invasive pneumococcal disease was observed in children receiving 1 or more doses, and the vaccine appears to reduce nasopharyngeal carriage of vaccine serotypes.^15,16

FAST TRACK

Despite vaccine shortages, a 29% decrease in the rate of pneumococal disease in both children and adults was observed

The older 23-valent polysaccharide vaccine does not stimulate good response in children younger than 2 years of age¹⁴ and does not reduce mucosal carriage or limit the spread of resistant strains.¹⁵

PCV-7 Supply Since 2000

In August 2001, a serious shortage of the vaccine developed in 34 state immunization programs.¹⁷ The following month, the CDC advised physicians to administer it only to children younger than 12 months and to those aged 1 to 5 years at increased risk of pneumococcal disease.¹⁸ As demand continued despite the change in recommendations, the CDC further changed recommendations to conserve vaccine supply, first suspending the fourth dose temporarily in healthy children¹⁹ and then discontinuing both the third and fourth doses.¹¹ In July 2004, production problems seemed to have resolved; the CDC recommended that every child receive 3 doses. In September, supplies were adequate for return to the 4-dose schedule.¹² As of June 2004, 67.7% of children aged 24 months had received 3 or more doses of PCV-7.²⁰ Thus, the effects of PCV-7 on the changing microbiology of AOM may only now, at the end of 2005, be fully realized.

Herd Immunity and Reduction in Carriage

Despite the shortages of vaccine during the first years of use, evidence of herd immunity and a decrease in antibiotic resistance in pneumococcal pathogens has been reported throughout the United States.^21,22 A 29% decrease in the rate of pneumococcal disease in both young children and adults has also been observed, along with a 35% reduction in the rate of disease caused by nonpenicillin-susceptible pneumococcal strains.²¹ The reduction in carriage among vaccinated children may be the reason.^21,22 Because of the impact of PCV-7, it will be important to record immunization history when collecting AOM data.

AOM treatment choices

The basis of recommendations for treating AOM depends on the presumed responsible pathogens, their susceptibility to antibiotics, and concerns for developing resistance, all influenced by clinical trial data. In practice, however, empiric choices are often made based on knowledge of local resistance patterns and of other patient characteristics; that is cost concerns, adverse event profiles, need to avoid initial treatment failure, adherence issues (eg, taste or palatability), convenience, and duration of dosing regimen.

All current guidelines recommend oral amoxicillin as first-line therapy in documented or presumed bacterial AOM. The 2004 American Academy of Pediatrics/American Academy of Family Physicians’ (AAP/AAFP) guidelines⁴ recommended increasing the dosage used for empiric treatment from 40 to 45 mg/kg/day to 80 to 90 mg/kg/day for all children. This was a result of concerns about the prevalence of penicillin-resistant S pneumoniae for which standard-dose amoxicillin is inadequate.²³

The guidelines were written and published before the data from the Kentucky and New York studies were available; therefore, although the guidelines recommended that empiric treatment of bacterial AOM should target S pneumoniae, H influenzae, and M catarrhalis, the pathogen shift discussed previously might today produce a modified antibiotic selection paradigm. The pathogen mix in persistent or recurrent AOM has already led to a guideline recommendation for high-dose amoxicillin/clavulanate, 90/6.4 mg/kg/day, cefdinir, cefprozil, cefpodoxime, cefuroxime, or ceftriaxone in these patients.²³

If an increase in the proportion of β-lactamase–producing pathogens due to PCV-7 occurs, amoxicillin may no longer be the best first choice.