key: cord-0805325-feakoftb authors: Champredon, David; Bancej, Christina; Lee, Liza; Buckrell, Steven title: Implications of the unexpected persistence of human rhinovirus/enterovirus during the COVID‐19 pandemic in Canada date: 2021-11-07 journal: Influenza Other Respir Viruses DOI: 10.1111/irv.12930 sha: 68e12671a18d24d6a79d6f3f8c65d19d9b252a9a doc_id: 805325 cord_uid: feakoftb Stringent public health measures imposed across Canada to control the COVID‐19 pandemic have nearly suppressed most seasonal respiratory viruses, with the notable exception of human rhinovirus/enterovirus (hRV/EV). Thanks to this unexpected persistence, we highlight that hRV/EV could serve as a sentinel for levels of contact rate in populations to inform on the efficiency, or the need of, public health measures to control the subsequent COVID‐19 epidemic, but also for future epidemics from other seasonal or emerging respiratory pathogens. persistence, we highlight that hRV/EV could serve as a sentinel for levels of contact rate in populations to inform on the efficiency, or the need of, public health measures to control the subsequent COVID-19 epidemic, but also for future epidemics from other seasonal or emerging respiratory pathogens. The causes of hRV/EV persistence are not fully understood yet. The fact that hRV/EV are non-enveloped may help sustain transmission thanks to their prolonged survival on surfaces. 6 Masks may be less effective at stopping droplets and aerosols transporting hRV/EV. 7 Another possibility may be that the population groups that drive hRV/EV transmission (typically young children) did not experience a contact rate reduction as effective as the groups driving SARS-CoV-2 transmission 8 when social distancing and other PHMs were in place. Alternatively, hRV/EV transmissibility to and among children may be similar to or higher than that of SARS-CoV-2 in the pediatric population. 9 Finally, the baseline prevalence of hRV/EV may be significantly higher than other respiratory infections (it also shows typical summertime persistence), allowing hRV/EV to rebound more easily when PHMs ease. The persistence of hRV/EV highlights a new and unsuspected role for this family of viruses as a sentinel for the transmission rate for respiratory pathogens. Notably, it highlighted the unique role for hRV/EV incidence to gauge the contact rate of a population (most likely its younger age groups, where hRV/EV symptomatic infections may be more prevalent. 10, 11 Direct measurements of contact rates through population surveys (for example, Drolet et al 12 ) are valuable but not sufficiently timely for surveillance, near-term forecasting and thus for early warning of resurgence/re-emergence potential for respiratory infectious diseases. Testing volumes for hRV/EV in Canada during the 2019-2020 and 2020-2021 seasons were higher than pre-pandemic levels ( Figure S4) , suggesting potential different demographics tested during non-pandemic seasons. Our observations support the continuation for routine acute respiratory infections surveillance that includes hRV/EV and encourages enhancements (e.g., sampling and reporting across all ages and spectrum of illness). The current COVID-19 pandemic has shown that monitoring the incidence of hRV/EV may have been undervalued so far: It could be useful for the subsequent SARS-CoV-2 epidemic activity and, for the longer term, potentially providing early warnings for other seasonal respiratory illnesses (notably influenza and RSV) as well as the transmission intensity at the time of introduction of another emerging respiratory pathogen in the monitored population. The peer review history for this article is available at https://publons. com/publon/10.1111/irv.12930. All data are publicly available. 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Laboratory respiratory pathogen surveillance reports Time trends in social contacts before and during the COVID-19 pandemic: the CONNECT study SUPPORTING INFORMATION Additional supporting information may be found in the online version of the article at the publisher's website. How to cite this article Implications of the unexpected persistence of human rhinovirus/enterovirus during the COVID-19 pandemic in Canada