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oai:figshare.com:article/33771742 2026-09-15T05:35:13Z category_427 portal_316 item_type_3 month_year_09_2026

Table 1_Temporal association between influenza A and B positivity and fever-clinic visit burden in Shanghai, China, 2022–2025: a retrospective time-series study.docx Shan Yu (219591) Tongtong Xu (4959505) Cunzheng Song (24912562) Xiaosong Chen (621316) Yueqiu Gao (8610597) Public Health and Health Services not elsewhere classified fever clinic healthcare utilization hospital preparedness influenza A influenza B respiratory virus surveillance Background<p>Temporal changes in respiratory virus circulation after the COVID-19 pandemic have created new challenges for fever-clinic preparedness. Outpatient influenza laboratory activity may provide useful operational information, but its type-specific temporal relationship with subsequent fever-clinic burden has not been well characterized.</p>Methods<p>We conducted a retrospective time-series study using aggregated fever-clinic visit records and outpatient influenza testing data from Renji Hospital, Shanghai, China, from 2022 to 2025. Lead–lag correlations were evaluated over a primary −28 to +28-day window using 7-day centered moving averages, with trailing moving averages and an extended −56 to +56-day window as sensitivity analyses. High-burden days were defined as days with visits at or above the 90th percentile. Adjusted quasi-Poisson models accounted for day of week, calendar month, calendar year, and testing volume. Additional analyses excluded 2022, evaluated adjacent 0–21-day influenza A leads, and used Newey–West autocorrelation-robust inference.</p>Results<p>We included 254,346 fever-clinic visits and 303,597 outpatient influenza testing episodes. Overall influenza positivity was 33.96%, with 84,819 influenza A-positive and 18,504 influenza B-positive episodes. Influenza A was the main contributor to increased overall activity, particularly in 2023 and 2025. Peak correlations occurred at −12 days for overall influenza positivity and −15 days for influenza A positivity, whereas influenza B peaked at the positive boundary of the primary window. In the extended analysis, the influenza B peak shifted to +50 days, indicating no stable leading relationship. High-burden days were preceded by higher overall influenza and influenza A positivity than reference days. In the conventional testing-volume-adjusted model, influenza A positivity at a 15-day lead was associated with daily fever-clinic visits, but this association was attenuated after exclusion of 2022 and was no longer statistically significant with Newey–West inference. Adjacent-lag analyses did not identify a robust positive day-specific association after false discovery rate correction.</p>Conclusion<p>Outpatient influenza A positivity showed clearer temporal alignment with subsequent fever-clinic burden than influenza B. Although the fixed 15-day estimate was sensitive to period restriction and residual serial correlation, influenza A positivity may still serve as a complementary hospital-level surveillance indicator rather than a stand-alone forecasting tool.</p> 2026-09-15T05:35:13Z Dataset Dataset 10.3389/fpubh.2026.1912599.s003 https://figshare.com/articles/dataset/Table_1_Temporal_association_between_influenza_A_and_B_positivity_and_fever-clinic_visit_burden_in_Shanghai_China_2022_2025_a_retrospective_time-series_study_docx/33771742 CC BY 4.0