Infections Caused by HRSV A ON1 Are Predominant among Hospitalized Infants with Bronchiolitis in São Paulo City

Abstract

Human respiratory syncytial virus is the main cause of respiratory infections in infants. Several HRSV genotypes have been described. Goals. To describe the main genotypes that caused infections in São Paulo (2013–2015) and to analyze their clinical/epidemiological features. Methods. 94 infants (0–6 months) with bronchiolitis were studied. Clinical/epidemiological information was collected; a search for 16 viruses in nasopharyngeal secretion (PCR-real-time and conventional, sequencing, and phylogenetic analyses) was performed. Results. The mean age was 2.4 m; 48% were male. The mean length of hospital stay was 4.4 d (14% in the Intensive Care Unit). The positive rate of respiratory virus was 98.9%; 73 cases (77.6%) were HRSV (76,7% HRSVA). HRSVA formed three clusters: ON1 (n = 34), NA1 (n = 1), and NA2 (n = 4). All HRSVB were found to cluster in the BA genotype (BA9-n = 10; BA10-n = 3). Clinical analyses showed no significant differences between the genotype AON1 and other genotypes. Conclusion. This study showed a high rate of HRSV detection in bronchiolitis. HRSVA ON1, which has recently been described in other countries and has not been identified in previous studies in the southeast region of Brazil, was predominant. The clinical characteristics of the infants that were infected with AON1 were similar to infants with infections by other genotypes.

Seasonality, molecular epidemiology, and virulence of Respiratory Syncytial Virus (RSV): A perspective into the Brazilian Influenza Surveillance Program

“…In our study, the median age of four months in hospitalized children with RSV confirms the higher prevalence in children younger than one year of age [ 2 ], which justifies why RSV vaccine candidates are aiming to protect, primarily, infants and young children [ 7 ]. Although the median hospitalization length of stay found here is similar to some other studies [ 27 , 28 ], notably, most of them report a shorter duration [ 1 , 4 , 25 ]. One hypothesis that could explain this finding is the fact that all children included in our study were diagnosed with SARI, which makes our study group a cohort with severe RSV infection.…”

“…RSV prevalence in different Brazilian regions is highly diverse, ranging from 7.7% to 77.6% [24][25][26]. In the ES state, from 2016 to 2018, the prevalence in hospitalized children up to 3 years of age was 56%.…”

Respiratory Syncytial Virus in Greece, 2016–2018

“…A possible association between RSV subtypes and disease severity has been investigated; the interest was renewed since the identification of the ON1 genotype, but it was concluded that it is not associated with disease severity [10,18]. This is in accordance with the results of the current study, since none of the RSV ON1-infected patients required mechanical ventilation or admission to intensive care, and no relation was observed between subtype and disease severity.…”

Molecular epidemiology of human respiratory syncytial virus among children in Japan during three seasons and hospitalization risk of genotype ON1

“…We also used this definition in this study and the p-distance showed that NA1 and ON1 could be classified into a single clade (p-distance, 0.039). However, we retained NA1 and ON1 as independent clades in this study to keep consistency from the previous reports by the reason for an unique 72 nucleotide duplication observed in ON1 [ 12 , 37 , 54 , 56 – 60 ].…”