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Dramatic Drop in Non-Covid Respiratory Viruses During Peak of Epidemic

MedicalResearch.com Interview with:
Dr Stephen Poole
BRC Clinical Research Fellow from the Southampton
Southampton, UK

MedicalResearch.com: What is the background for this study?

Response: Our understanding of how the emergence of COVID 19 (SARS-CoV-2) has effected existing seasonal respiratory viruses, like influenza or common cold viruses, is limited. Many labs stopped or reduced their testing for these other respiratory viruses during the first epidemic peak as healthcare providers were trying to save resources for COVID-19 testing. We know that the viruses in circulation prior to COVID caused a lot of exacerbations of asthma and chronic obstructive pulmonary disease (COPD) but it is unclear whether this is the case with SARS-CoV-2.

The aims of our study were to measure the impact of the emergence of SARS-CoV-2 on other respiratory viruses and to compare the patterns of illness. Our group in Southampton, UK led by Dr Tristan Clark were uniquely positioned to be able to do this. We have run 3 large trials in the last 5 winters which have tested for a wide range of respiratory viruses all in the same group of patients: adults arriving in hospital with a recent onset respiratory illness. We use this to compare the proportion of tests which were positive in the height of the COVID pandemic (March-May) with the same time period in previous years.

MedicalResearch.com: What are the main findings? Could the drop be due to the rise in social distancing, cleaning and mask wearing? 

Response: There was a dramatic drop in the proportion of non-COVID respiratory viruses which were detected during the peak of the epidemic. In 2020 only 4.1% of patients had one of these viruses compared to 54% of patients tested in previous years.

Interventions to curb the spread of COVID-19 are highly likely to have been responsible for some of this reduction. We know that other respiratory viruses are spread in similar ways, and generally have a shorter incubation period, so distancing measures may well have impacted the non-COVID viruses earlier on. It has been theorised for influenza that the spread of previous epidemics may have been slowed by interaction with other existing respiratory viral infections (i.e. the presence of one virus ‘pushes out’ another). This is a possible explanation for the absence of non-SARS-CoV-2 viruses during the peak of the pandemic.

We also found in the study that the proportion of patients who had exacerbations of asthma or COPD were much higher for existing respiratory viruses (37%) that for SARS-CoV-2 (1%). This is relevant as these conditions require different treatment to pneumonia, the disease most frequently seen in hospitalised patients with COVID-19.

MedicalResearch.com: What should readers take away from your report?

Response: The emergence of SARS-CoV-2 was associated with a reduction in other circulating respiratory viruses. Hospitalisation with seasonal respiratory virus infection disproportionately involved adults with existing lung disease, unlike COVID-19, which did not.

MedicalResearch.com: Is there anything else you would like to add?

Response: Our manuscript about this is still under review at a medical journal, so has not yet been peer reviewed. Our findings should be considered preliminary until this has been finalised (expected in next few weeks). Having said this, the large studies from which the data is taken are all peer-reviewed and either in press, or already available from large medical journals.


ECCVID abstract discussing the emergence of SARS-CoV-2 was associated with a large drop in circulation of other common respiratory viruses during the first wave.


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Last Updated on September 29, 2020 by Marie Benz MD FAAD