Seasonal Respiratory Virus Circulation was Diminished during the
COVID-19 Pandemic
Abstract
Background: Measures introduced during the COVID-19 pandemic intended to
address the spread of SARS-CoV-2 may also influence the incidence of
other common seasonal respiratory viruses (SRV). This evaluation reports
laboratory confirmed cases of common SRV in a well-defined region of
central Canada to address this issue. Methods: Surveillance data for
common non-SARS-CoV-2 SRV in the Ottawa, Canada region was provided by
the Eastern Ontario Regional Laboratory Association (EORLA) reference
virology lab. Weekly reports of the number of positive tests and
proportion that yielded positive results was analyzed from August 26,
2018 to January 2, 2022. Results: A drastic reduction in influenza and
other common SRV was observed during the 2020-2021 influenza season in
the Ottawa region. Influenza was virtually undetected post SARS-CoV-2
emergence. Rhinoviruses and enteroviruses were the only viruses that
remained relatively unaffected during this period. Conclusions: We
speculated that the introduction of non-pharmaceutical measures
including masking to prevent SARS-CoV-2 transmission contributed to the
near absence of SRV in the Ottawa region. These measures should remain a
key component in addressing spikes in SRV activity and future pandemics.