Role of Respiratory Viruses in Acute Upper and Lower Respiratory Tract Illness in the First Year of Life

TLDR

Acute respiratory illnesses are a leading cause of morbidity and mortality in early childhood, yet control efforts are limited and most research focuses on hospitalized or closed‑population cohorts. The study aimed to define the viral causes of upper and lower respiratory illnesses in infants during their first year by prospectively following 263 children in a community cohort. Researchers collected nasopharyngeal aspirates for every ARI episode and used PCR to detect common respiratory viruses, classifying episodes as upper or lower respiratory illnesses, with or without wheeze, in 263 infants who experienced an average of 4.1 episodes. Rhinoviruses were detected in 48.5% of ARI and accounted for over ten times as many upper respiratory illnesses and more than three times as many lower respiratory and wheezing lower respiratory illnesses compared to RSV, making.

Abstract

Although acute respiratory illnesses (ARI) are major causes of morbidity and mortality in early childhood worldwide, little progress has been made in their control and prophylaxis. Most studies have focused on hospitalized children or children from closed populations. It is essential that the viral etiology of these clinical diseases be accurately defined in the development of antiviral drugs.To investigate the role of all common respiratory viruses as upper and lower respiratory tract pathogens in the first year of life.This community-based birth cohort study prospectively collected detailed information on all ARI contracted by 263 infants from birth until 1 year of age. Nasopharyngeal aspirates were collected for each ARI episode, and all common respiratory viruses were detected by polymerase chain reaction. Episodes were classified as upper respiratory illnesses or lower respiratory illnesses (LRI), with or without wheeze.The majority reported 2-5 episodes of ARI in the first year (range, 0-11 episodes; mean, 4.1). One-third were LRI, and 29% of these were associated with wheeze. Viruses were detected in 69% of ARI; most common were rhinoviruses (48.5%) and respiratory syncytial virus (RSV) (10.9%). Compared with RSV, >10 times the number of upper respiratory illnesses and >3 times the number of both LRI and wheezing LRI were attributed to rhinoviruses.Rhinoviruses are the major upper and lower respiratory pathogens in the first year of life. Although RSV is strongly associated with severe LRI requiring hospitalization, the role of rhinoviruses as the major lower respiratory pathogens in infants has not previously been recognized.