Prevalence of human bocavirus infections in Europe. A systematic review and meta-analysis.

Human bocaviruses (HBoVs) are recently described as human emergent viruses, especially in young children. In this study, we undertook a systematic review and meta-analysis to estimate their prevalence in Europe. PubMed, Web of Science and Scopus databases were systematically screened for clinical studies, up to October 2020. Study eligibility criteria were primary full-text articles from clinical studies, conducted using valid screening test methods and published in peer-reviewed journals, in English or Spanish and from European countries. The overall pooled prevalence, prevalence by country as well as the prevalence of HBoV as a single or co-pathogen were estimated using a random-effects model. Sub-group and meta-regression analyses explored potential sources of heterogeneity in the data. A total of 35 studies involving 32,656 subjects from 16 European countries met the inclusion criteria. Heterogeneity (I2  = 97.0%, p < .01) was seen among studies; HBoV prevalence varied from 2.0 to 45.69% with a pooled estimate of 9.57% (95%CI 7.66-11.91%). The HBoV prevalence both as a single infection (3.99%; 95%CI 2.99-5.31%) or as co-infection with other viruses (5.06%; 95%CI 3.88-6.58%) was also analysed. On a geographic level, prevalence by country did not show statistical differences, ranging from 3.24% (Greece) to 21.05% (Denmark). An odds ratio analysis was also included in order to evaluate the relevance of the variable 'age' as a risk factor of HBoV infection in children <5 years old. The OR value of 1.77 (95%CI 1.13-2.77; p < .01) indicated that being <5 years old is a risk factor for HBoV infection. This study showed that HBoV has a moderate prevalence among European countries.