Circulation of Respiratory Viruses in Hospitalized Adults before and during the COVID-19 Pandemic in Brescia, Italy: A Retrospective Study

Abstract

Different preventive public health measures were adopted globally to limit the spread of SARS-CoV-2, such as hand hygiene and the use of masks, travel restrictions, social distance actions such as the closure of schools and workplaces, case and contact tracing, quarantine and lockdown. These measures, in particular physical distancing and the use of masks, might have contributed to containing the spread of other respiratory viruses that occurs principally by contact and droplet routes. The aim of this study was to evaluate the prevalence of different respiratory viruses (influenza viruses A and B, respiratory syncytial virus, parainfluenza viruses 1, 2, 3 and 4, rhinovirus, adenovirus, metapneumovirus and human coronaviruses) after one year of the pandemic. Furthermore, another aim was to evaluate the possible impact of these non-pharmaceutical measures on the circulation of seasonal respiratory viruses. This single center study was conducted between January 2017–February 2020 (pre-pandemic period) and March 2020–May 2021 (pandemic period). All adults >18 years with respiratory symptoms and tested for respiratory pathogens were included in the study. Nucleic acid detection of all respiratory viruses was performed by multiplex real time PCR. Our results show that the test positivity for influenza A and B, metapneumovirus, parainfluenza virus, respiratory syncytial virus and human coronaviruses decreased with statistical significance during the pandemic. Contrary to this, for adenovirus the decrease was not statistically significant. Conversely, a statistically significant increase was detected for rhinovirus. Coinfections between different respiratory viruses were observed during the pre-pandemic period, while the only coinfection detected during pandemic was between SARS-CoV-2 and rhinovirus. To understand how the preventive strategies against SARS-CoV-2 might alter the transmission dynamics and epidemic patterns of respiratory viruses is fundamental to guide future preventive recommendations.

SARS-CoV-2 and other airborne respiratory viruses in outdoor aerosols in three Swiss cities before and during the first wave of the COVID-19 pandemic

“…2 Table. 1) in Switzerland ( FOPH, 2019 ; Cabecinhas et al 2021 ), similar as the situations in other places around the world ( Chiapinotto et al, 2021 , De Francesco et al, 2021 , Hsieh et al, 2020 , Kuitunen, 2021 ). Similarly, significant spring peaks of three other abundant viruses were also detected in our study (SI.…”

“…Due to the control measures, seasonal epidemics of influenza, HRSV and HMPV either ended earlier ( Kuitunen, 2021 , Redlberger-Fritz et al, 2021 ), were delayed ( Delestrain et al, 2021 , Williams et al, 2021 ) or even prevented ( Kuitunen 2021 ). In contrast, the case number of adenovirus did not decrease significantly ( De Francesco et al 2021 ), while Rhinovirus cases were commonly observed to be increased together with SARS-CoV-2 cases ( De Francesco et al, 2021 , Haapanen et al, 2021 , Redlberger-Fritz et al, 2021 ). These two along with enterovirus and HCoV-NL63 were also commonly observed in children in 2020–2021 winter ( Diesner-Treiber et al 2021 ).…”

“…Secondly, the relationship between SARS-CoV-2 and other respiratory viruses in aerosols is also largely unknown. So far, coinfections have been reported between SARS-CoV-2 and influenza A ( Dadashi et al 2021 ), influenza B ( Dadashi et al 2021 ), human parainfluenza virus (HPIV1) 1 ( Boschiero et al 2022 ), HPIV2 ( Boschiero et al 2022 ), HPIV3 ( Boschiero et al 2022 ), HPIV4 ( Rodriguez et al 2020 ), human coronaviruses (HCoV) NL63 ( Pigny et al 2021 ), HCoV-OC43 ( Boschiero et al 2022 ), HCoV-HKU1 ( Boschiero et al 2022 ), HCoV-229E ( Lau et al 2021 ), human respiratory syncytial virus (HRSV) ( Jiang et al 2020 ), human metapneumovirus (HMPV) ( Jiang et al, 2020 , Pigny et al, 2021 ), adenovirus ( Pigny et al 2021 ), and picornaviruses which include rhinovirus ( Boschiero et al, 2022 , De Francesco et al, 2021 , Pigny et al, 2021 ) and enterovirus ( Boschiero et al 2022 ). Moreover, lockdowns and other measures including mass masking and universal hygiene also seriously impacted other infectious respiratory diseases causing a significant decline of infections during the pandemic ( Chiapinotto et al, 2021 , Hsieh et al, 2020 ).…”

“…Moreover, lockdowns and other measures including mass masking and universal hygiene also seriously impacted other infectious respiratory diseases causing a significant decline of infections during the pandemic ( Chiapinotto et al, 2021 , Hsieh et al, 2020 ). Incidence numbers of influenza A and B, HMPV, HPIV, HRSV and other HCoV decreased or disappeared during the pandemic ( De Francesco et al, 2021 , Diesner-Treiber et al, 2021 ). Due to the control measures, seasonal epidemics of influenza, HRSV and HMPV either ended earlier ( Kuitunen, 2021 , Redlberger-Fritz et al, 2021 ), were delayed ( Delestrain et al, 2021 , Williams et al, 2021 ) or even prevented ( Kuitunen 2021 ).…”

The impact of COVID-19 pandemic on influenza surveillance: a systematic review and meta-analysis

“…The representative national network of primary care practitioners regularly conducts sentinel influenza surveillance among 1-6% of the WHO-European region population 20 . Hence, for studies with no information on the target population, 6% of the region's total population was taken as the target population 7,11,14,16,17 .…”