Seasonal respiratory virus circulation was diminished during the COVID-19 pandemic.

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 Ottawa, Canada, was provided by the Eastern Ontario Regional Laboratory Association (EORLA) reference virology lab. Weekly reports of the number of positive tests and the proportion that yielded positive results were 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 nonpharmaceutical 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.

Seasonality of Respiratory Viruses Including SARS-CoV-2

We propose that a reservoir of respiratory viruses in clumps of micro-sized dust exists in tropospheric clouds from which virions can be seasonally released into the lower atmosphere and thence to ground level. Respiratory Syncytial Virus (RSV), Seasonal Influenza and Human Para Influenza Virus (HPIV) are all diseases that fall in this category, including SARS-CoV-2. The seasonal incidence of disease at ground level would appear to be patchy over distance scales that are largely dictated by viral-laden dust cloud size modulated by scales of atmospheric turbulence. This could produce clustering of cases in space and time that has given rise to ‘contagion' concepts of community spread and of superspreaders. © 2022 by World Scientific Publishing Co. Pte. Ltd.

A Silver Lining? Fewer Non-Severe Acute Respiratory Syndrome Coronavirus 2 Respiratory Viruses During the Coronavirus Disease 2019 Pandemic.

Nonpharmaceutical interventions (NPIs) have "flattened the curve" of the coronavirus disease 2019 pandemic; however the effect of these interventions on other respiratory viruses is unknown. We used aggregate level case count data for 8 respiratory viruses and compared the institutional and statewide case counts before and during the period that NPIs were active. We observed a 61% decrease (incidence rate ratio, 0.39; 95% confidence interval, .37-.41; P < .001) in non-severe acute respiratory syndrome coronavirus 2 respiratory viral infections when NPIs were implemented. This finding, if further verified, should guide future public health initiatives to mitigate viral epidemics.

Prevalence of Co-Infections with Respiratory Viruses in Individuals Investigated for SARS-CoV-2 in Ontario, Canada.

BACKGROUND: Co-infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with respiratory viruses, bacteria and fungi have been reported to cause a wide range of illness. OBJECTIVES: We assess the prevalence of co-infection of SARS-CoV-2 with seasonal respiratory viruses, document the respiratory viruses detected among individuals tested for SARS-CoV-2, and describe characteristics of individuals with respiratory virus co-infection detected. METHODS: Specimens included in this study were submitted as part of routine clinical testing to Public Health Ontario Laboratory from individuals requiring testing for SARS-CoV-2 and/or seasonal respiratory viruses. RESULTS: Co-infection was detected in a smaller proportion (2.5%) of individuals with laboratory confirmed SARS-CoV-2 than those with seasonal respiratory viruses (4.3%); this difference was not significant. Individuals with any respiratory virus co-infection were more likely to be younger than 65 years of age and male than those with single infection. Those with SARS-CoV-2 co-infection manifested mostly mild respiratory symptoms. CONCLUSIONS: Findings of this study may not support routine testing for seasonal respiratory viruses among all individuals tested for SARS-CoV-2, as they were rare during the study period nor associated with severe disease. However, testing for seasonal respiratory viruses should be performed in severely ill individuals, in which detection of other viruses may assist with patient management.

Climate and Human coronaviruses 229E and Human coronaviruses OC43 Infections: Respiratory Viral Infections Prevalence in Hospitalized Children in Cheonan, Korea.

The study of climate and respiratory viral infections using big data may enable the recognition and interpretation of relationships between disease occurrence and climatic variables. In this study, realtime reverse transcription quantitative PCR (qPCR) methods were used to identify Human respiratory coronaviruses (HCoV). infections in patients below 10 years of age with respiratory infections who visited Dankook University Hospital in Cheonan, South Korea, from January 1, 2012, to December 31, 2018. Out of the 9010 patients who underwent respiratory virus real-time reverse transcription qPCR test, 364 tested positive for HCoV infections. Among these 364 patients, 72.8% (n = 265) were below 10 years of age. Data regarding the frequency of infections was used to uncover the seasonal pattern of the two viral strains, which was then compared with local meteorological data for the same time period. HCoV-229E and HCoV-OC43 showed high infection rates in patients below 10 years of age. There was a negative relationship between HCoV-229E and HCoV-OC43 infections with air temperature and wind-chill temperatures. Both HCoV-229E and HCoV-OC43 rates of infection were positively related to atmospheric pressure, while HCoV-229E was also positively associated with particulate matter concentrations. Our results suggest that climatic variables affect the rate in which children below 10 years of age are infected with HCoV. These findings may help to predict when prevention strategies may be most effective.