Background Human bocavirus (HBoV) is frequently detected in the airways of young children with respiratory symptoms. Because it is frequently co-detected with other viruses the role of HBoV1 in respiratory illness has been questioned.

Aims

• To evaluate the outcomes of children on the Paediatric Intensive Care Unit (PICU) with HBoV infection.

• To analyse the clinical features of HBoV infection.

• To clinically compare HBoV isolated infections and HBoV positive children with co-infections

Methods A retrospective study over 5 years was conducted in children admitted to PICU with respiratory symptoms requiring intubation and in asymptomatic control children.

Results HBoV was detected in 13 children admitted to the PICU over 5 years. This was confirmed by performing PCR on samples taken at bronchoscopy via brochioalveolar lavage. About 46% of these infections occurred November and Feburary with a second incidence peak in April (38.4% of cases). 5 (38%) of children had an isolated bocavirus infection compared with 9 (61%) who had co-infections with other viruses; rhinovirus (30.7%) adenovirus (15.3%) parainfluenza (15.3%) coronavirus (7.7%). Clinical features associated with HBoV infection were similar to those observed with HBoV with co-infections. All of the children were intubated, (mean 6 days median 4 days) Those with HBoV co-infections were intubated for on average 1 day and 4 h longer than children with isolated bocavirus infection indicating a more severe course of infection in those with HBoV co-infection. However those with just HBoV infection fared much better only being intubated for an average of 4 days (p = 0.04) indicating that the severity is significantly reduced if HBoV is the only pathogen.

Conclusion The difference observed in HBoV infections and HOBV co-infections provides support for a role of this virus in respiratory illness. The frequent associations of HBoV with other respiratory viruses might be explained by the persistence of HBoV in the respiratory tract. The observed increase in length intubation associated with HBoV co-infection warrants further investigation.