NECROTIZING PNEUMONIA AMONG ITALIAN CHILDREN IN THE PNEUMOCOCCAL
CONJUGATE VACCINE ERA
Abstract
ABSTRACT Background: Necrotizing pneumonia (NP) is a severe complication
of community-acquired pneumonia. The impact of 13-valent pneumococcal
conjugate vaccine (PCV13) on the epidemiology of NP in children has not
been formally assessed. Patients and methods: Medical records of
children <18 years admitted with NP to two pediatric hospitals
in Italy between 2005 through 2019 were retrospectively reviewed. The
following 4 periods were defined: 2005-2010 (pre-PCV13), 2011-2013
(early post-PCV13), 2014-2016 (intermediate post-PCV13), and 2017-2019
(late post-PCV13). Results: Forty-three children (median age, 44 months)
were included. Most of them (93%) were previously healthy. No
differences in age, sex, season of admission, comorbidity, clinical
presentation, or hospital course were identified between pre-PCV13 and
post-PCV13 periods. A significant decrease in the rate of NP-associated
hospitalizations was found between the early (1.5/1000 admissions/year)
and the intermediate (0.35/1000 admissions/year) post-PCV13 period
(p=0.001). Streptococcus pneumoniae was the most common agent detected
in both periods (pre-PCV13: 11/18, 61%; post-PCV13: 13/25, 52%).
Serotype 3 was the most common strain in both periods (pre-PCV13: 3/11,
27%; post-PCV13; 4/13, 31%). There were no changes in the bacterial
etiology over time, but most patients with Streptococcus pyogenes or
Staphylococcus aureus infection were admitted during the post-PCV13
period. Conclusions: The hospitalization rate for NP in children
decreased a few years after the implementation of PCV13 immunization in
Italy. However, an increased trend in admissions was found thereafter.
S. pneumoniae was the most frequent causal agent in both pre- and
post-PCV13 periods. Pneumococcal serotypes were mainly represented by
strain 3.