Impact of non-pharmaceutical interventions on circulating respiratory viruses during the COVID-19 pandemic in Turkey

BACKGROUND: Non-pharmaceutical interventions (NPIs) applied to limit the SARS-CoV-2 pandemic also affect the circulation and seasonal characteristics of other respiratory viruses.OBJECTIVES: Assess the impact of NPIs on the spread and seasonal characteristics of non-SARS-CoV-2 respiratory viruses and examine viral respiratory co-infections.DESIGN: Retrospective cohortSETTING: Single center in Turkey.PATIENTS AND METHODS: Syndromic multiplex viral polymerase chain reaction (mPCR) panel results of patients admitted to the Ankara Bilkent City Hospital with symptoms of acute respiratory tract infec-tion between April 1, 2020 and October 30, 2022 were evaluated. Two study periods before and after 1 July 2021, when the restrictions were discontinued, were statistically analyzed and compared to determine the effect of NPIs on circulating respiratory viruses.MAIN OUTCOME MEASURES: Prevalence of respiratory viruses as determined by syndromic mPCR panel.SAMPLE SIZE: 11 300 patient samples were evaluated.RESULTS: At least one respiratory tract virus was detected in 6250 (55.3%) patients. Of these, at least one respiratory virus was detected in 5% in the first period (between April 1, 2020 and June 30, 2021, when NPIs were applied), and in 95% in the second period (between July 1, 2021 and October 30, 2022, when NPIs were relaxed). After the removal of NPIs, there was a statistically significant increase in hRV/EV, RSV-A/B, Flu A/H3, hBoV, hMPV, PIV-1, PIV-4, hCoV-OC43, PIV-2 and hCoV-NL63 (P<.05). In the 2020-2021 season, when strict NPIs were applied, all respiratory viruses evaluated did not have the usual sea-sonal peak and there were no seasonal influenza epidemics during this period.CONCLUSIONS: NPIs resulted in a dramatic decrease in the preva-lence of respiratory viruses and notable disruption of seasonal charac-teristics.LIMITATIONS: Single-center study and retrospective.CONFLICT OF INTEREST: None.