3.2 Analysis of RV infection trends before and after the ending of Dynamic Zero-COVID Policy
Throughout the study period, 4,242 (21.55%) patients tested positive for RV. RV infections exhibited multiple peaks, with the highest infection rate observed in ARTIs during April 2021 and November 2022 (Figure 1). The overall prevalence of RV infections among pediatric inpatients with ARTIs was 24.36% (1150/4721) in 2021, decreasing to 22.54% (1178/5227) in 2022, and further to 19.67% (1914/9732) in 2023 (Table 2). Statistical analysis revealed significant difference indicating a disparity in the distribution of RV between different years (χ² = 45.45, p < 0.001). Pairwise comparisons further revealed statistically significant variations in the distribution of RV across these years, indicating that the overall infection rate of RV continues to decline from 2021 to 2023. In 2022, Hainan encountered two significant COVID-19 pandemic in March and August. Subsequently, stringent non-pharmaceutical interventions (NPIs) were implemented and maintained across the year until the repeal of the zero-COVID policies. Despite these measures, a notable suppression of RV infections was not observed, with the infection rate exhibiting only a marginal decrease from 24.36% in 2021. Considering gender divisions, RV infection rates were 22.75% (2759/12126) in males and 17.08% (1290/7554) in females among all inpatients with ARTIs, with a statistically significant difference observed between these rates (χ² = 91.75, p<0.001). The chi-square test for gender differences across the years did not reveal statistical significance (χ2=0.20, p=0.91), indicating a stable gender distribution over time (Table 2).
Specifically, in the spring of 2021, the RV infection rate was observed to be 37.62%, decreasing to 14.59% in the summer. The rate subsequently increased to 21.81% in the autumn and further to 26.56% in the winter, evidencing significant seasonal variation (χ² = 157.88, p < 0.001). The following year, 2022, exhibited a similar pattern with rates of 24.18% in spring, 12.48% in summer, a notable rise to 39.92% in autumn, and 20.77% in winter, again demonstrating significant seasonal differences (χ² = 216.25, p < 0.001). In 2023, the infection rates were 23.50% in spring, 16.83% in summer, 20.07% in autumn, and 17.67% in winter, maintaining the trend of significant seasonal variability (χ² = 38.74, p < 0.001). These results are in concordance with existing literature, which indicates a higher prevalence of RV in the autumn, winter, and spring months, with a reduced incidence observed during the summer. This consistency reinforces the established understanding of RV seasonal dynamics[20].