Spread and clinical severity of respiratory syncytial virus A genotype ON1 in Germany, 2011-2017

Abstract

Background: The Respiratory Syncytial Virus (RSV) A genotype ON1, which was first detected in Ontario (Canada) in 2010/11, appeared in Germany in 2011/12. Preliminary observations suggested a higher clinical severity in children infected with this new genotype. We investigated spread and disease severity of RSV-A ON1 in pediatric in- and outpatient settings.

Methods: During 2010/11 to 2016/17, clinical characteristics and respiratory samples from children with acute respiratory tract infections (RTI) were obtained from ongoing surveillance studies in 33 pediatric practices (PP), one pediatric hospital ward (PW) and 23 pediatric intensive care units (PICU) in Germany. RSV was detected in the respiratory samples by PCR; genotypes were identified by sequencing. Within each setting, clinical severity markers were compared between RSV-A ON1 and RSV-A non-ON1 genotypes.

Results: A total of 603 children with RSV-RTI were included (132 children in PP, 288 in PW, and 183 in PICU). Of these children, 341 (56.6%) were infected with RSV-A, 235 (39.0%) with RSV-B, and one child (0.2%) with both RSV-A and RSV-B; in 26 (4.3%) children, the subtype could not be identified. In the 341 RSV-A positive samples, genotype ON1 was detected in 247 (72.4%), NA1 in 92 (26.9%), and GA5 in 2 children (0.6%). RSV-A ON1, rarely observed in 2011/12, was the predominant RSV-A genotype in all settings by 2012/13 and remained predominant until 2016/17. Children in PP or PW infected with RSV-A ON1 did not show a more severe clinical course of disease compared with RSV-A non-ON1 infections. In the PICU group, hospital stay was one day longer (median 8 days, inter-quartile range (IQR) 7-12 vs. 7 days, IQR 5-9; p = 0.02) and duration of oxygen treatment two days longer (median 6 days, IQR 4-9 vs. 4 days, IQR 2-6; p = 0.03) for children infected with RSV-A ON1.

Conclusions: In children, RSV-A ON1 largely replaced RSV-A non-ON1 genotypes within two seasons and remained the predominant RSV-A genotype in Germany during subsequent seasons. A higher clinical severity of RSV-A ON1 was observed within the group of children receiving PICU treatment, whereas in other settings clinical severity of RSV-A ON1 and non-ON1 genotypes was largely similar.

Keywords: Children; Disease severity; Epidemiology; RSV-A ON1; Respiratory tract infection.

Fig. 1

Seasonal distribution of 341 children with acute respiratory tract infection with RSV-A ON1 (n = 247) or RSV-A non-ON1 infection (n = 94) in pediatric practices (PP), a general pediatric ward (PW) and pediatric intensive care units (PICU) in Bavaria/Germany, 2010/11 to 2016/17. The columns represent the number of children included per RSV season. Note that any inter-setting comparison should be regarded with caution, as data were collected from separate surveillance studies differing in observation period, number of participating units, and inclusion criteria: in 33 PP, 72 children from 1 to 5 years of age with RSV-A infection were included during the RSV-seasons 2012/13 to 2014/15. In the PW, 165 children up to 16 years of age with RSV-A infection were included from 2011/12 to 2016/17. In 23 PICU, 104 children from 1 month to16 years of age with RSV-A infection were included from 2010/11 to 2012/13, and in 9 PICU, children from 1 month to 5 years of age were included during 2013/14 to 2016/17. The numbers per setting and RSV-A subtype are listed in Additional file 2: Table S1