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. 2025 Apr 9;8(4):e70618.
doi: 10.1002/hsr2.70618. eCollection 2025 Apr.

A Retrospective Analysis of Changes in Respiratory Pathogens During the Influenza Season Before and After the Relaxation of Non-Pharmaceutical Intervention Policies

Lin Zhang  1 , Xiang Long  1 , Yun-Ju Yuan  1 , Su-Li Zhao  2
Affiliations

A Retrospective Analysis of Changes in Respiratory Pathogens During the Influenza Season Before and After the Relaxation of Non-Pharmaceutical Intervention Policies

Lin Zhang et al. Health Sci Rep. .

Abstract

Background and aims: The COVID-19 pandemic has profoundly impacted the transmission dynamics and epidemiology of respiratory pathogens, primarily due to non-pharmaceutical interventions (NPIs). This study aims to evaluate the effects of NPIs on the characteristics of winter respiratory pathogens.

Methods: This study involved the collection of respiratory pathogen test results from all patients tested at our hospital during two distinct periods: September 2021 to May 2022 and September 2022 to May 2023. The comparison of positive rates was performed using the χ 2 test. A p-value less than 0.05 indicates no statistical significance. Data analysis was performed using SPSS version 22.0.

Results: The predominant pathogen during the 2021/2022 flu seasons was identified as Inf B (1095/9309, 11.76%). Conversely, during the 2022/2023 flu seasons, Inf A emerged as the most prevalent pathogen (4040/18,770, 21.52%). Notably, the positive rates of parainfluenza virus and M. pneumoniae were lower in the 2022/2023 flu seasons, while the positive rate of L. pneumophila was higher. Furthermore, the number of positive SARS-CoV-2 cases in the 2022/2023 flu seasons increased nearly fivefold compared to the 2021/2022 flu seasons.

Conclusions: The findings of this study suggest that the relaxation of NPIs has a notable influence on the transmission of certain respiratory pathogens within the population. We propose the implementation of ongoing surveillance to monitor the epidemiology and evolutionary dynamics of various respiratory pathogens, particularly in situations where NPIs are no longer necessary.

Keywords: COVID‐19 pandemic; NPIs; SARS‐CoV‐2; influenza; respiratory pathogens.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
The influenza A and B virus circulation during season 2021/2022 and 2022/2023.
Figure 2
Figure 2
The positive numbers of SARS‐CoV‐2 and other respiratory pathways. Blue: positive numbers of SARS‐CoV‐2; Orange: positive numbers of other respiratory pathogens.
Figure 3
Figure 3
The position rate of pathogens in flu seasons. The positivity rate of pathogens in 2021/2022 flu season (blue lines) and 2022/2023 (green lines) are presented. The unlocking in 2022/2023 flu season starting from December is shown (black arrow).
See this image and copyright information in PMC

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