Community-acquired pneumonia in children — a changing spectrum of disease
Pediatr Radiol
Community-acquired pneumonia in children - a changing spectrum of disease
David M. le Roux 0 1
Heather J. Zar 0 1
0 Department of Paediatrics, New Somerset Hospital , Cape Town , South Africa
1 5th Floor ICH Building Red Cross War Memorial Children's Hospital , Klipfontein Road Cape Town, 7700 , South Africa
2 David M. le Roux
Pneumonia remains the leading cause of death in children outside the neonatal period, despite advances in prevention and management. Over the last 20 years, there has been a substantial decrease in the incidence of childhood pneumonia and pneumonia-associated mortality. New conjugate vaccines against Haemophilus influenzae type b and Streptococcus pneumoniae have contributed to decreases in radiologic, clinical and complicated pneumonia cases and have reduced hospitalization and mortality. The importance of co-infections with multiple pathogens and the predominance of viral-associated disease are emerging. Better access to effective preventative and management strategies is needed in low- and middle-income countries, while new strategies are needed to address the residual burden of disease once these have been implemented.
Children; Conjugate vaccination; Epidemiology; Haemophilus influenzae; Incidence; Pneumococcus; Pneumonia; Radiology; Vaccination
Introduction
Pneumonia has been the leading cause of death in children
younger than 5 years for decades. Although there have been
substantial decreases in overall child mortality and in
pneumonia-specific mortality, pneumonia remains the major
single cause of death in children outside the neonatal period,
causing approximately 900,000 of the estimated 6.3 million
child deaths in 2013 [
1
]. Substantial advances have occurred
in the understanding of risk factors and etiology of pneumonia,
in development of standardized case definitions, and in
prevention with the production of improved vaccines and in treatment.
Such advances have led to changes in the epidemiology,
etiology and mortality from childhood pneumonia. However in
many areas access to these interventions remains sub-optimal,
with large inequities between and within countries and regions.
In this paper we review the impact of recent preventative and
management advances in pneumonia epidemiology, etiology,
radiologic presentation and outcome in children.
Epidemiology and burden of pneumonia in childhood
The overall burden of childhood pneumonia has been reduced
substantially over the last decade, despite an increase in the
global childhood population from 605 million in 2000 to 664
million in 2015 [
2
]. Recent data suggest that there has been a
25% decrease in the incidence of pneumonia, from 0.29
episodes per child year in low- and middle-income countries in
2000, to 0.22 episodes per child year in 2010 [
3
]. This is
substantiated by a 58% decrease in pneumonia-associated
disability-adjusted life years between 1990 and 2013, from 186 million
to 78 million as estimated in the Global Burden of Disease study
[
1
]. Pneumonia deaths decreased from 1.8 million in 2000 to
900,000 in 2013 [
1
]. These data do not reflect the full impact of
increasingly widespread use of pneumococcal conjugate
vaccine in low- and middle-income countries because the incidence
of pneumonia and number of deaths are likely to decrease still
further as a result of this widespread intervention [
4
].
Notwithstanding this progress, there remains a
disproportionate burden of disease in low- and middle-income
countries, where more than 90% of pneumonia cases and deaths
occur. The incidence in high-income countries is estimated at
0.015 episodes per child year, compared to 0.22 episodes per
child year in low- and middle-income countries [
3
]. On
average, 1 in 66 children in high-income countries is affected by
pneumonia per year, compared to 1 in 5 children in low- and
middle-income countries. Even within low- and
middleincome countries there are regional inequities and challenges
with access to health care services: up to 81% of severe
pneumonia deaths occur outside a hospital [
5
]. In addition to a
higher incidence of pneumonia, the case fatality rate is
estimated to be almost 10-fold higher in low- and middle-income
countries as compared to high-income countries [
3, 5
].
Childhood pneumonia can also lead to significant
morbidity and chronic disease. Early life pneumonia can impair
longterm lung health by decreasing lung function [
6
]. Severe or
recurrent pneumonia can have a worse effect on lung function;
increasing evidence suggests that chronic obstructive
pulmonary disease might be related to early childhood pneumonia
[
7, 8
]. A meta-analysis of the risk of long-term outcomes after
childhood pneumonia categorized chronic respiratory
sequelae into major (restrictive lung disease, obstructive lung
disease, bronchiectasis) and minor (chronic bronchitis, asthma,
abnormal pulmonary function) groups [9]. The risk of
developing at least one of the major sequelae (...truncated)