Significant impact of nationwide SARS-CoV-2 lockdown measures on the circulation of other respiratory virus infections in Austria

Abstract

Background: Since the worldwide spread of SARS-CoV-2, different European countries reacted with temporary national lockdowns with the aim to limit the virus transmission in the population. Also Austria started a lockdown of public life in March 2020.

Objectives: In this study we investigated whether the circulation of different respiratory virus infections in Austria, as assessed by the established respiratory virus surveillance system, is affected by these measures as well and may reflect the success of the lockdown in limiting respiratory virus transmission.

Study design: Sentinel data obtained for influenza virus, respiratory syncytial virus, human metapneumovirus and rhinovirus cases were analyzed and compared between the season 2019/2020 and the five previous seasons.

Results: We observed a rapid and statistically significant reduction of cumulative cases for all these viruses within short time after the lockdown in March 2020, compared to previous seasons (each p < 0.001). Also, sentinel screening for SARS-CoV-2 infections was performed and a decrease of SARS-CoV-2 was seen after the lockdown. While for the seasonally occurring viruses as influenza, respiratory syncytial virus or human metapneumovirus the lockdown led to the end of the annual epidemics, a re-increase of rhinovirus infections was observed after liberalization of numerous lockdown measures.

Conclusions: Our data provide evidence that occurrence of different respiratory virus infections reflect not only the efficiency of lockdown measures taken against SARS-CoV-2 but it shows also the effects of lockdown releases on the transmission of respiratory viruses.

Keywords: COVID19 lockdown; Lockdown; Lockdown impact; Respiratory viruses; SARS-CoV-2.

Fig. 1

Number of Influenza virus, Respiratory Syncytial Virus (RSV), human Metapneumovirus (hMPV) and Rhinovirus (RHIV) detections per week during the period between week 40/2019 and 28/2020. Color coding shows the intensity of virus circulation for each virus, green = no activity, yellow = sporadic detections, orange = medium activity, red = peak activity, red arrow indicates state of lockdown (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article).

Fig. 2

Pattern in the circulation dynamics of (a) Influenza virus, (b) Respiratory Syncytial Virus (RSV), (c) human Metapneumovirus (hMPV) and (d) Rhinovirus (RHIV) of the six consecutive seasons 2014/15 to 2019/20. As Influenza, RSV, and hMPV exhibit clear seasonal activity, for a better comparability the weeks of the seasonal virus circulation was indicated. (a) (b) and (c): first week of seasonal virus circulation was defined as the first week of each season where >5% of samples were tested positive; as RHIV circulation has no expressed seasonality the calendar weeks are indicated.