The impact of the COVID-19 pandemic on influenza, respiratory syncytial virus, and other seasonal respiratory virus circulation in Canada

Abstract

Background The ongoing coronavirus disease 2019 (COVID-19) pandemic has resulted in implementation of public health measures worldwide to mitigate disease spread, including; travel restrictions, lockdowns, messaging on handwashing, use of face coverings and physical distancing. As the pandemic progresses, exceptional decreases in seasonal respiratory viruses are increasingly reported. We aimed to evaluate the impact of the pandemic on circulation of influenza, respiratory syncytial virus and other seasonal respiratory viruses in Canada. Methods Epidemiologic data were obtained from the Canadian Respiratory Virus Detection Surveillance System. Weekly data from the week ending 30th August 2014 until the week ending the 13th February 2021 were analysed. We compared trends in laboratory detection and test volumes during the 2020/2021 influenza season with baseline pre-pandemic seasons from 2014 to 2019. Findings We observed a dramatically lower percentage of tests positive for all seasonal respiratory viruses during 2020-2021 compared to baseline. For influenza A and B the percent positive decreased to 0.0017 and 0.0061 times that of baseline respectively and for RSV, the percent positive dropped to 0.0145 times that of baseline. Ongoing detection of enterovirus/rhinovirus occurred, with regional variation in the epidemic patterns and intensity. Interpretation We report an effective absence of the annual seasonal epidemic of most seasonal respiratory viruses in 2020/2021. This dramatic decrease is likely related to implementation of multi-layered public health measures during the pandemic. The impact of such measures may have relevance for public health practice in mitigating seasonal respiratory virus epidemics and for informing responses to future respiratory virus pandemics.

Interactions among common non‐SARS‐CoV‐2 respiratory viruses and influence of the COVID‐19 pandemic on their circulation in New York City

“…In addition, we found a significantly lower number of cases were detected for several viruses (i.e., CoV-OC43, CoV-229E, HMPV, PIV-2, PIV-4, RSV, and IV) in 2020-2021, suggesting reduced circulation of these viruses, during the COVID-19 pandemic. Consistently, other studies have also found that circulation of influenza, seasonal coronaviruses, RSV, PIV, and HMPV reduced substantially in the United States8 and Canada15 and that RV was less affected,8,15 during 2020-2021.…”

Retrospective diagnosis of SARS-CoV-2 infection in patients with Long COVID by measuring specific T cell mediated IL-2 release.

“…This is likely to be a key issue as the SARS-CoV-2 T cell reactive unexposed individuals within the negative control group were likely infected with one or more of the four human circulating endemic coronaviruses that are known to cause the common cold. It is less likely that our Long COVID cohort have been infected recently with other coronaviruses, as infections with all respiratory viruses dropped during 2020 due to non-pharmacological interventions including social distancing and wearing of face masks, directed against SARS-CoV-2 [36,45]. This will however become an issue for retrospective diagnosis of SARS-CoV-2 infection using T cellbased assays as countries end restrictions on social interactions, which will likely see resurfacing and the spread of circulating endemic coronaviruses.…”

COVID‐19 implications for pediatric anesthesia: Lessons learnt and how to prepare for the next pandemic

“…Gradual opening of the society and relaxation of COVID-19 physical and social distancing measures has created an unseen RSV resurgence in the most unlikely season of spring/summer and virtually overrunning many pediatric departments to an extent that ambulatory and surgical procedures are being canceled on a similar scale as during the initial phases of the COVID-19 pandemic. 5,6 This temporal shift of RSV infection is indeed unique, and data do give cause for concern on how the impact of reduced immunity among children not having been exposed to pathogens such as influenza and RSV virus will come back to test our capabilities and capacity in the upcoming winter in the Northern Hemisphere. 6 This will certainly influence our daily practices when providing anesthesia and perioperative care not only in terms of respiratory and circulatory support but also in terms of infectious disease control.…”

“…5,6 This temporal shift of RSV infection is indeed unique, and data do give cause for concern on how the impact of reduced immunity among children not having been exposed to pathogens such as influenza and RSV virus will come back to test our capabilities and capacity in the upcoming winter in the Northern Hemisphere. 6 This will certainly influence our daily practices when providing anesthesia and perioperative care not only in terms of respiratory and circulatory support but also in terms of infectious disease control. We are certainly obliged to consider the risk of simultaneous and nosocomial respiratory infections (i.e., COVID-19 variants, RSV, influenza A and B, haemophilus influenzae, rhinovirus, and pneumococcal variants) in children admitted to hospital, but also among parents and staff.…”