Fig. 2

Respiratory virus PCR-positive rates in groups. The respiratory viral infection rate in the AP group was 47%, showing no significant difference compared to the non-AP (50%) and AB (53%) groups (Chi-square test, p = 0.873, Cramér's V = 0.036). The chi-square test did not show a statistically significant association between the variables (p = 0.873). Furthermore, the effect size as measured by Cramér's V was 0.036, indicating that there is a negligible relationship between the groups. Based on this, it is unlikely that increasing the sample size would meaningfully alter the results, as the observed association appears to be minimal. Abbreviations: AP, aspiration pneumonia; non-AP, pneumonia except for aspiration pneumonia; AB, acute bronchitis