2. Materials and methods
The protocol for the search and study characterization was designeda priori and is available (Rawal et al., 2019c). The term “frequency of detection” (i.e., number of positive samples/total samples tested) was used for cross-sectional studies to avoid term “prevalence” as we did not want to mislead the readers to think that all studies reported actual prevalence estimates. Anticipating based on quick search that most eligible studies have a limited sample size and have not considered all the age groups in that sampled population, and thus are likely not a true estimate of the astrovirus prevalence within that population. This study considered including data from records, following 4 phases (Fig 1).