School of Public Health, Nanjing Medical University, Nanjing, China.
Department of Acute Infectious Disease Control and Prevention, Nanjing Municipal Center for Disease Control and Prevention, Nanjing, China.
J Med Virol. 2022 May;94(5):1959-1966. doi: 10.1002/jmv.27553. Epub 2022 Jan 8.
Since the pandemic of coronavirus disease-19 (COVID-19), the incidence of influenza has decreased significantly, but there are still few reports in the short period before and after the pandemic period. This study aimed to explore influenza activity and dynamic changes before and during the pandemic.
A total of 1 324 357 influenza-like illness (ILI) cases were reported under the ILI surveillance network from January 1, 2018, to September 5, 2021, in Nanjing, of which 16 158 cases were detected in a laboratory. Differences in ILI and influenza were conducted with the χ test.
The number of ILI cases accounted for 8.97% of outpatient and emergency department visits. The influenza-positive ratio (IPR) was 7.84% in ILI cases. During the COVID-19 pandemic, ILI% and IPR dropped by 6.03% and 11.83% on average, respectively. Besides this, IPR rose slightly in Week 30-35 of 2021. Not only differences in gender, age, and employment status, but also the circulating strains had changed from type A to B through the COVID-19 pandemic.
The level of influenza activity was severely affected by COVID-19, but it seems that it is inevitable to be vigilant against the co-circulation in the future.
自 2019 冠状病毒病（COVID-19）大流行以来，流感发病率显著下降，但大流行前后的短期报告仍较少。本研究旨在探讨大流行前后流感活动和动态变化。
2018 年 1 月 1 日至 2021 年 9 月 5 日，在南京流感样病例（ILI）监测网络中报告了 1324357 例 ILI 病例，其中 16158 例在实验室中检测到。采用卡方检验比较 ILI 和流感之间的差异。
ILI 病例数占门诊和急诊就诊人数的 8.97%。ILI 病例的流感阳性率（IPR）为 7.84%。在 COVID-19 大流行期间，ILI%和 IPR 分别平均下降了 6.03%和 11.83%。此外，2021 年第 30-35 周 IPR 略有上升。不仅性别、年龄和就业状况的差异，而且循环毒株也通过 COVID-19 大流行从 A 型转变为 B 型。
流感活动水平受到 COVID-19 的严重影响，但未来似乎仍不可避免地要警惕共同循环。
