Studying PCV impact on clinical presentation of otitis media helps to understand its pathogenesis

BACKGROUND

Complex otitis media (OM) may present with intact tympanic membrane or spontaneous otorrhea. We compared dynamics of intact tympanic membrane and spontaneous otorrhea OM following 7- and 13-valent conjugated vaccines (PCV7, PCV13) implementation, since differences in dynamics may imply different underlying mechanisms.

METHODS

A prospective, population-based, active surveillance. Episodes with middle-ear fluid cultures in children < 3 years were included. Defined sub-periods were: pre-pneumococcal conjugated vaccines (PCV) (2004-2008); PCV7 (2009-2011); PCV13 (2014-2016).

RESULTS

Of 7705 episodes, 57.2% had intact tympanic membrane, 16.8% spontaneous otorrhea, 26.0% unknown. In the pre-PCV period, the spontaneous otorrhea group was older and had higher proportions of factors associated with recurrence/chronicity. During the PCV7 period, spontaneous otorrhea and intact tympanic membrane episodes caused by PCV13 serotypes decreased significantly (43% and 51%, respectively) and those caused by non-PCV13 serotypes and culture-negative episodes increased significantly. However, rates increases were steeper in the spontaneous otorrhea group for both non-PCV13 serotypes (117% vs. 38%) and culture-negative (720% vs. 69%). In the spontaneous otorrhea group, nontypeable Haemophilus influenzae rates increased non-significantly by 10% and all-cause OM rates increased significantly by 56%, while in the intact tympanic membrane group the respective rates decreased significantly by 22% and 11%. These trends were especially pronounced in ages 24-35 months. Despite these differences, after PCV13 introduction, both spontaneous otorrhea and intact tympanic membrane rates declined for all outcomes.

CONCLUSIONS

Spontaneous otorrhea was associated with older age, frequent history of complex OM and delayed PCV impact, suggesting a higher proportion of advanced-stage complex OM.

Comparative incidence dynamics and serotypes of meningitis, bacteremic pneumonia and other-IPD in young children in the PCV era: Insights from Israeli surveillance studies

INTRODUCTION

Widespread introduction of pneumococcal conjugated vaccines (PCVs) impacted on invasive pneumococcal disease (IPD). However, IPD reduction may not be similar in all outcomes within IPD. We assessed PCV7/PCV13 impact on pneumococcal meningitis, bacteremic pneumonia (BP) and other (non-meningitis, non-pneumonia) IPD episodes in children <5years in Israel.

METHODS

A prospective, population-based, active nationwide surveillance. All pneumococcal invasive episodes with positive blood/CSF cultures, July 2000 through June 2016, were included. Three sub-periods were defined: pre-PCV (2000-2008), PCV7 (2009-2011) and PCV13 (2014-2016). Incidence rate ratios (IRRs) were calculated.

RESULTS

Overall, 4321 episodes were recorded; 456 (10.6%) meningitis, 1478 (34.2%) pneumonia and 2387 (55.2%) other-IPD. In the pre-PCV period, proportion of serotypes in PCV13, but not in PCV7 (mainly serotypes 1, 5 and 19A) was higher in BP (43.3%) compared with other-IPD episodes (32.8%, p<0.001) and similar to that of meningitis (37.6%, p=0.1). The proportion of episodes in children <12months was higher in meningitis (52.1%) compared with pneumonia (23.2%) and other-IPD episodes (39.5%; p<0.001 for both). The declines of the 3 entities were not similar; Meningitis rate non-significantly declined by 24% (IRR=0.76; 95% CI 0.57-1.01), while BP and other-IPD rates significantly declined by 57% and 70%, respectively. In contrast to other entities, BP did not decline significantly after PCV7 introduction but started to decline only after PCV13 introduction. Rates of meningitis, pneumonia and other-IPD caused by PCV13-serotypes (VT13) substantially declined by 88%, 95% and 97%, respectively, comparing PCV13 and the pre-PCV periods. However, diseases caused by non-VT13 increased by 256%, 302% in meningitis and pneumonia, respectively, but only 116% in other-IPD.

CONCLUSIONS

Following PCV7/PCV13 introduction, rates of episodes caused by VT13 were substantially reduced in all 3 groups. However, differences in age distribution, serotype replacement and specific serotype decrease suggest different pathogenesis and host susceptibility between the 3 entities.