FIGURE 2.

Enrollment and NP/OP PCR positivity by month of study. A: PERCH enrollment by month, all cases, controls, and CXR+ cases. CXR+ defined as consolidation and/or other infiltrate on chest radiograph (subset of the all case groups).B: Enrollment and NP/OP PCR positivity for select viruses by month, CXR+ cases. CXR+ defined as consolidation and/or other infiltrate on chest radiograph. HMPV, human metapneumovirus A/B; NP/OP, nasopharyngeal/oropharyngeal; Para 1, parainfluenza virus types 1; Para 3, para, parainfluenza virus types 3; RSV, respiratory syncytial virus A/B.