Impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on acute mastoiditis (AM) in children
AM is a suppurative infection of the mastoid air cells and the most common intra-temporal complication of acute otitis media (AOM) in children. Incidence rates of AM in the developed world range from 1.2 to 15.0/100,000 children <18 years of age. The most common pathogens causing AOM and also AM are Streptococcus pneumoniae, non-typeableHaemophilus influenzae, Streptococcus pyogenes, Moraxella catarrhalis and Fusobacterium necrophorum.
The pneumococcal conjugate vaccine (PCV) in its 7-valent form (PCV7) was introduced in the USA more than 20 years ago and in Israel, in its 7 and 13-valent (PCV13) from 2009 and 2010, respectively. Both vaccines had been shown to decrease some of the pneumococcal-related morbidities, including AOM. The effect of the sequential introduction of the 2 PCVs on AOM was described in two studies from Israel by Ben-Shimol et al., who showed a significant decline in the incidence of both pneumococcal and nonpneumococcal AOM that required tympanocentesis in children <3 years. Additional prospective studies from USA and Europe reported that PVC13 prevents pneumococcal AOM caused by vaccine serotype.
Taking into consideration the fact that the microbiology of AOM and AM are quite similar, it was expected the incidence of AM will also decrease following the introduction of the PCVs. However, the worldwide incidence rates of AM reported following the introduction of the PCVs are contradictory. The incidence of AM reported in southern Israel in a tertiary care medical center continued to increase during the last two decades (from 6.1/100,000 during 1990–2001 to 11.5/100, 000 during 2002–2012). An additional retrospective Italian study, reporting on a total of 913 children with AM diagnosed during 2002-2013, showed increasing rates of AM only among older children (≥4 years) . On the other hand, other studies performed before the introduction of PCV13 in Western Europe reported no changes in AM rates, with pediatric incidence rates between 4.8 to 6.3/100,000].
The information on the impact of PCV13 vaccination on the rates and microbiology of AM is limited. We will present the evidence accumulated in the medical literature regarding the impact of PCV13 on AM in children, together with new data analyzing the trends in AM incidence, microbiology, complications and management in children <15 years of age in southern Israel, before and after the PVC13 introduction (2005-2016).