Effect of Pneumococcal Conjugate Vaccine on Nasopharyngeal Bacterial Colonization During Acute Otitis Media

Abstract

The heptavalent pneumococcal conjugate vaccine (PCV7) has been shown to reduce the incidence of acute otitis media (AOM) caused by Streptococcus pneumoniae by 34% and reduces the overall incidence of AOM by 6% to 8%. More recent studies have shown increases in the proportion of Haemophilus influenzae and Moraxella catarrhalis in the middle-ear fluid of PCV7-immunized children. There has been no report on the effect of PCV7 on all 3 bacterial pathogens combined, either in the middle-ear fluid or nasopharynx of individual children with AOM. We investigated the impact of PCV7 on nasopharyngeal colonization with bacterial pathogens during AOM in the pre-PCV7 and post-PCV7 vaccination eras. Four hundred seventeen children (6 months to 4 years of age) were enrolled onto AOM studies between September 1995 and December 2004. Of these, 200 were enrolled before the vaccine use (historical controls), and 217 were enrolled after the initiation of PCV7 vaccination (101 were underimmunized, and 116 were immunized). Although the nasopharyngeal colonization rate for S pneumoniae was not different between the 3 groups, a significantly higher proportion of PCV7-immunized children with AOM were colonized with M catarrhalis. Overall, the mean number of pathogenic bacteria types isolated from immunized children (1.7) was significantly higher than in controls (1.4). The increase in bacterial colonization of the nasopharynx during AOM could be associated with an increase in AOM pathogens and theoretically can predispose PCV7-immunized children with AOM to a higher rate of antibiotic treatment failure or recurrent AOM.

Effect of Pneumococcal Vaccination on Nasopharyngeal Carriage of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus in Fijian Children

“…Several studies investigated effects of pneumococcal vaccination on S. aureus, and most did not find any increases in S. aureus colonization associated with PCV7 (4, 5, 13) or PCV9 (14) vacci- (24). Consistent with our findings, studies on the effects of pneumococcal vaccination in healthy children found no increases in carriage of H. influenzae (14,35) or M. catarrhalis (35).…”

Pilot comparative study on the health of vaccinated and unvaccinated 6- to 12- year old U.S. children

“…A search of VAERS for "Cases where age is under 1 and onset interval is 0 or 1 or 2 or 3 or 4 or 5 or 6 or 7 days and Symptom is otitis media" [63] revealed that 438,573 cases were reported between 1990 and 2011, often with fever and other signs and symptoms of inflammation and central nervous system involvement. One study [64] assessed the nasopharyngeal carriage of S. pneumoniae, H. influenzae, and M. catarrhalis during AOM in fully immunized, partly immunized children with 0 or 1 dose of Pneumococcal Conjugate Vaccine-7 (PCV7), and "historical control" children from the pre-PCV-7 era, and found an increased frequency of M. catarrhalis colonization in the vaccinated group compared to the partly immunized and control groups (76% vs. 62% and 56%, respectively). A high rate of Moraxella catarrhalis colonization is associated with an increased risk of AOM [65].…”

Haemophilus influenzae Infections in the H. influenzae Type b Conjugate Vaccine Era

“…Widespread administration of this vaccine has resulted in a dramatic reduction in nasopharyngeal colonization by the 7 pneumococcal serotypes included in the vaccine. This has been accompanied by several important changes in the distribution of bacterial pathogens that cause otitis media: (i) a reduction in pneumococcal vaccine serotypes, (ii) a relative increase in pneumococcal nonvaccine serotypes, and (iii) a relative increase in H. influenzae and Moraxella catarrhalis causing nasopharyngeal colonization and otitis media (4,9,36). Two new pneumococcal conjugate vaccines have recently been approved for use, and these include a 13-valent vaccine in the United States and a 10-valent vaccine in Europe in which pneumococcal polysaccharides are conjugated to protein D, a surface protein of H. influenzae (34).…”