FIRS The Global Impact of Respiratory Disease – Second Edition | Page 17

Acute lower
respiratory tract infection
Scope of the disease
Lower respiratory tract infection and
pneumonia are two of the leading causes
of death, accounting for more than 4
million fatalities annually. It is a particularly
important cause of death in low- and middle-
income countries [27]. Lower respiratory
tract infection kills more people than human
immunodefi ciency virus (HIV), TB and malaria
combined [6]. It is the leading cause of death
in children under 5 years of age outside
the neonatal period [6]. Pneumonia killed
920,136 children aged under 5 years in 2015,
accounting for 15% of the deaths in this age
group [28]. It is also the second leading cause
of years of life lost due to premature mortality
[27] and one of the most frequent reasons for
hospitalisation.
Risk factors for pneumonia include being very
young or elderly, crowded living conditions,
malnutrition, HIV infection, lack of breast-
feeding in infants, lack of immunisation,
chronic health conditions and exposure to
tobacco smoke or indoor air pollutants.
Streptococcus pneumoniae remains the most
frequent bacterial cause of pneumonia and
killed 393,000 children aged under 5 years
in 2015 [1]. HIV infection increases the risk of
pneumonia caused by this organism twenty-
fold, although the incidence of severe disease
has declined with better immunisation and
the use of antiretroviral therapy. Pneumonia
can also lead to chronic respiratory diseases,
such as bronchiectasis.
Viral respiratory infections can occur in
epidemics and spread rapidly within
16
communities across the globe. Every year,
infl uenza leads to respiratory tract infections in
5–15% of the population and severe illness in
3–5 million people [29]. Respiratory syncytial
virus (RSV) is the most common cause of
acute respiratory infection in children, causing
almost 34 million episodes annually. More than
90% of deaths from RSV respiratory infection
in children occur in low- and middle-income
countries [30].
Ominously, new respiratory pathogens are
emerging. In 2003, severe acute respiratory
syndrome (SARS), caused by a previously
unrecognised coronavirus, rapidly spread
throughout the world. Its lethality mobilised
international efforts that rapidly identifi ed
the cause and the method of spread.
Stringent infection control measures reduced
its spread effectively and no further cases
were identifi ed [31]. The risk of another
global epidemic caused by a new virus or a
mutation in a known virus has encouraged
health offi cials and researchers to fi nd ways
to limit or prevent such a catastrophe. These
events can stress national healthcare systems,
leading to widespread disaster. Respiratory
viruses can spread quickly because of the
ease of transmission, as has been seen in past
infl uenza pandemics.
Prevention
Childhood respiratory disease can be
prevented or ameliorated by several measures:
improving childhood nutrition and promoting
breastfeeding (both of which improve
immune status); ensuring comprehensive
immunisation; improving living conditions to
prevent crowding; avoiding tobacco smoke
Forum of International Respiratory Societies