Incidence of viral respiratory infections in a prospective cohort of outpatient and hospitalized children aged ≤5 years and its associated cost in Buenos Aires, Argentina

Abstract

Background: Although information about the incidence of viral respiratory illnesses and their associated cost can help health officials explore the value of interventions, data are limited from middle-income countries.

Methods: During 2008-2010, we conducted a prospective cohort study and followed ~1,800 Argentinian children aged ≤5 years to identify those children who were hospitalized or who sought care at an emergency room with any acute respiratory infection sign or symptom (e.g., rhinorrhea, cough, wheezing, tachypnea, retractions, or cyanosis). Respiratory samples were obtained for respiratory syncytial virus, influenza, parainfluenza, adenovirus, and metapneumovirus testing by immunofluorescence and for rhinovirus by real-time reverse transcription polymerase chain reaction.

Results: The incidence of respiratory syncytial virus (24/1000 children-years), human metapneumovirus (8/1000 children-years), and influenza (8/1000 children-years) illnesses was highest among hospitalized children aged <6 months and decreased among older children. In contrast, the incidence of rhinovirus was highest (12/1000 children-years) among those aged 6-23 months. In the emergency room, the incidence of rhinovirus was 459; respiratory syncytial virus 352; influenza 185; parainfluenza 177; metapneumovirus 130; and adenovirus 73/1,000 children-years. The total cost of hospitalization was a median of US$529 (Interquartile range, US$362-789).

Conclusions: Our findings indicate that respiratory viruses, in particular rhinovirus, respiratory syncytial virus, metapneumovirus, and influenza may be associated with severe illness causing substantial economic burden.

Fig. 1

Proportion of children testing positive for respiratory viruses each month during 2008–2010 From July 2008 to December 2010, respiratory samples from Argentina children aged ≤5 years, who were hospitalized or who sought care at an emergency room with any acute respiratory infection sign or symptom (e.g., rhinorrhea, cough, wheezing, tachypnea, retractions, or cyanosis), were taken and tested for several respiratory viruses (Human metapneumovirus, adenvirus, Para-influenza, influenza, RSV and rhinovirus). While rhinoviruses were detected throughout the year, RSV, human metapneumovirus, influenza, adenovirus, and parainfluenza 1 through 3 viruses were also identified starting April or May, with peak activity during June or July, during Argentina’s austral winter

Fig. 2

Proportion of hospitalized, emergency room, and asymptomatic control children testing positive for respiratory viruses, 2008–2010. From July 2008 to December 2010, respiratory samples from Argentina children aged ≤5 years, who were hospitalized or who sought care at an emergency room with any acute respiratory infection sign or symptom (e.g., rhinorrhea, cough, wheezing, tachypnea, retractions, or cyanosis), were taken and tested for several respiratory viruses (Human metapneumovirus, adenvirus, Para-influenza, influenza, RSV and rhinovirus). RSV, human metapneumovirus, and influenza were frequently identified among hospitalized children aged <6 months (37, 18, 13 %, respectively) but seldom among asymptomatic controls (<3 %). Rhinovirus, however, was identified among 40 % of hospitalized children and 22 % of asymptomatic controls