Introduction
Respiratory viruses are a leading cause of morbidity and mortality among
children and adults worldwide 1, 2. The burden of
respiratory viruses is disproportionately high in low-to-middle income
countries (LMICs) 3, 4. Specific respiratory virus
infections (RVIs), such as influenza and respiratory syncytial virus
(RSV), and more recently SARS-CoV-2, are the major contributors to this
high burden of disease 3, 4, 5. In 2018, influenza
virus accounted for 870,000 influenza-virus-associated hospital
admissions, 15,300 in-hospital deaths, and around 34,800 overall
influenza-virus-associated acute lower respiratory infections (ALRI)
deaths among children under 5 years of age 6. Around
82% of in-hospital deaths due to influenza virus occurred in low-income
countries (LICs) and LMICs 6. Whereas, it is estimated
that RSV accounts for 33 million cases and 118,000 deaths annually in
children under five, of which 22 million cases and 103,000 deaths are in
LICs and LMICs 7. In addition to the annual impact of
common respiratory viruses like influenza and RSV, emerging respiratory
viruses such as avian influenza A (H5N1) virus, influenza A(H1N1) pdm09
virus, MERS-CoV, avian influenza A(H7N9), and most recently, SARS-CoV-2
represent elevated threats to global health security 1,
8. Collectively these viruses markedly contribute to respiratory
disease morbidity and mortality in populous countries like Indonesia9, 10, 11.
Indonesia is a tropical archipelago of islands with high humidity and a
population of around 271 million 12. Indonesia has
year-round respiratory virus activity with seasonal peaks ranging
between October and April, which corresponds with the wet and dry
seasons 13. More recent surveillance efforts have
shown dominant seasonal influenza activity occurring December through
February with clear patterns of phased infections among the different
seasonal influenza virus strains (influenza A/pH1, influenza A/H3, and
influenza B) 10, 14. Far less is known about the
epidemiology and burden of RSV and other respiratory viral infections in
Indonesia as comprehensive surveillance for non-influenza viruses is
limited. Indonesia also has a growing population of animal reservoirs
for zoonotic infections including poultry, rodents, wild birds, dogs,
pigs, and monkeys 15. Given that Indonesia is an LMIC
with a large and diverse population, the risk of viral respiratory
disease burden is high. Therefore, this literature review was conducted
to better understand the epidemiology of viral respiratory disease in
Indonesia.