Figure 1

Flow chart of the birth cohort study: demonstrating the number of participants with detailed quantities of various samples tested and valid questionnaire information. *Nasopharyngeal swab was performed at 1 month of age.
Flow chart of the birth cohort study: demonstrating the number of participants with detailed quantities of various samples tested and valid questionnaire information. *Nasopharyngeal swab was performed at 1 month of age.