Fig. 3: Correlations between RSV test positivity rate and environmental factors (3-week prior) and distributions of environmental factors by epidemic and non-epidemic seasons.

A Nationwide Spearman correlation between RSV test positivity rate and environmental factors (3-week prior), as well as correlations among environmental factors. Red shades indicate positive correlations, and blue shades indicate negative correlations. Darker colors denote stronger associations. Cells marked with “X” indicate nonsignificant correlations with two-sided p > 0.05. B Region-specific correlations between RSV test positivity rate and environmental factors (3-week prior). Colors range from red (positive) to blue (negative), with darker shades indicating stronger correlations. The dotted line separates regions located above and below the Tropic of Capricorn. C Distributions of environmental factors during epidemic and non-epidemic seasons defined using the 10% test positivity rate as a cutoff. Panel (1) shows air pollutants, and panel (2) shows meteorological factors. Grey box plots represent epidemic seasons, and yellow box plots represent non-epidemic seasons. ***denotes statistically significant differences between seasons assessed by the two-sided Mann–Whitney U test, and “ns” indicates nonsignificant differences where p > 0.05.