Influenza A(H1N1)pdm09 infection and viral load analysis in patients with different clinical presentations

Alves, Vitória Rodrigues Guimarães; Perosa, Ana Helena; Luna, Luciano Kleber de Souza; Cruz, Jéssica Santiago; Conte, D.; Bellei, Nancy

doi:10.1590/0074-02760200009

Cited by 17 publications

(15 citation statements)

References 14 publications

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“…Therefore, it is likely that these patients were already clearing the virus particularly that they were on antiviral therapy. These findings are consistent with previous studies showing that the highest influenza viral load is detected on day 0 of hospitalization in oseltamivir treated patients [ 67 , 68 ]. Our findings are also in line with studies done in college communities and multicentre areas, which revealed a negative association between the detection of aerosolized IAV and the time elapsed since illness onset [ 51 , 58 ].…”

Section: Discussionsupporting

confidence: 93%

Detection of influenza virus in air samples of patient rooms

Chamseddine

Soudani

Kanafani

et al. 2021

Journal of Hospital Infection

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Background Understanding the transmission and dispersal of influenza and respiratory syncytial virus (RSV) via aerosols is essential for the development of preventative measures in hospital environments and healthcare facilities. Methods During the 2017-2018 influenza season, patients with confirmed influenza or RSV infections were enrolled. Room air samples were collected close to (0.30 m) and far (2.20 m) from the patient’s head. Real-time polymerase chain reaction (PCR) was used to detect and quantify viral particles in the air samples. Plaque assay was used to determine the infectiousness of the detected viruses. Findings Fifty-one air samples were collected from the rooms of 29 patients with laboratory-confirmed influenza; 51% of the samples tested positive for influenza A virus (IAV). Among IAV-positive patients, 65% were emitters (have at least one positive air sample) reflecting a higher risk of nosocomial transmission compared to non-emitters. The majority (61.5%) of the IAV-positive air samples were collected at 0.3 m distance from the patients’ head, while the remaining were collected at 2.2 m. The positivity rate of IAV in air samplers was influenced by the distance from the patient’s head and the day of collection post-hospital admission. Only three patients with RSV infection were recruited and none were emitters. Conclusion This study demonstrates that influenza can be aerosolized beyond one meter in patient rooms, a distance considered to be safe by infection control practices. Further investigations are needed to determine the extent of infectivity of the aerosolized virus particles.

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Section: Discussionsupporting

confidence: 93%

Detection of influenza virus in air samples of patient rooms

Chamseddine

Soudani

Kanafani

et al. 2021

Journal of Hospital Infection

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“…Varying clinical presentations and virus shedding rates have been correlated with numbers of influenza virus copies in nasopharyngeal samples. 16,17 In this study, we have shown that virus copies were about two logs higher in the NPS samples of patients with mild disease compared to those with moderate or severe disease, though this was not statistically significant. Thus, disease severity/symptomatology of COVID-19 does not correlate with SARS-CoV2 copies in NPS samples: this may reflect stage in the evolution of disease.…”

Section: Sars-cov2 Primarily Infects Epithelial Cells Lining the Oral Oropharyngeal And Respiratorycontrasting

confidence: 53%

Implications in the quantitation of SARS-CoV2 copies in concurrent nasopharyngeal swabs, whole mouth fluid and respiratory droplets

Kannian

Jayaraman²,

Alamelu

et al. 2021

Preprint

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ImportanceThe nasopharyngeal swab (NPS) is considered the ideal diagnostic specimen for Covid-19, while WMF is recently promoted due to collection simplicity and importance in disease transmission. There is limited knowledge on the relative viral load in these samples – NPS, whole mouth fluid (WMF) and respiratory droplets (RD; another important source in transmission), on how the loads vary with disease severity and on how much virus is shed.ObjectiveTo quantify and compare SARS-CoV2 copies in the NPS, WMF and RD samples, and correlate with disease severity.DesignCross sectional study.SettingTertiary care multi-speciality hospital with limited resources in a low-to-middle income country.ParticipantsEighty suspected COVID-19 patients were recruited from the COVID-19 out-patient clinic and hospital isolation wards.InterventionConcurrent NPS, WMF and RD samples were collected from all the recruited patients and tested for SARS-CoV2 copies by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).Main outcomes and measuresThe main outcome was COVID-19 measured by SARS-CoV2 quantitative RT-PCR in NPS samples. COVID-19 disease severity was determined according to NIH criteria. Virus shedding was defined as the presence of SARS-CoV2 copies in the WMF and RD samples.ResultsSARS-CoV2 was detected in 55/80 (69%) of the NPS samples. Of these 55, WMF and RD samples were positive in 44 (80%) and 17 (31%), respectively. The concordance of WMF with NPS was 84% (p=0.02). SARS-CoV2 copy numbers were comparable in the NPS (median: 8.74×10^5) and WMF (median: 3.07×10^4), but lower in RD samples (median: 3.60×10^2). Patients with mild disease had higher copies in the NPS (median: 3.46×10^6), while patients with severe disease had higher copies in the WMF (median: 1.34×10^6) and RD samples (median: 4.29×10^4). The 25-75% interquartile range of NPS SARS-CoV2 copies was significantly higher in the WMF (p=0.0001) and RD (p=0.01) positive patients.Conclusion and relevanceSARS-CoV2 copies are highest in NPS samples. WMF is a reliable surrogate sample for diagnosis. High copy numbers in the NPS imply initial virological phase and higher risk of virus shedding via WMF and RD.Key pointsQuestionHow the numbers of SARS-CoV2 copies in nasopharyngeal swab (NPS) samples might reflectvirus shedding from the whole upper aerodigestive tract and indicatedisease severity?FindingsIn this cross-sectional study involving 80 suspected COVID-19 patients, the data indicate higher SARS-CoV2 copies in NPS samples of patients with mild disease,and in the whole mouth fluid (WMF) and respiratory droplet (RD) samples of patients with severe disease. Patients with higher SARS-CoV2 copies in the NPS shed the virus in the WMF and RD samples at statistically higher levels.MeaningHigh SARS-CoV2 copies in NPS samples imply initial virological phase withhigh levels of shedding through both WMF and RD.

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“…Lee et al, 2011;C. C. Li et al, 2010;Loeb et al, 2012;Lu et al, 2012;Meschi et al, 2011;Ngaosuwankul et al, 2010;Rath et al, 2012;Rodrigues Guimaraes Alves et al, 2020;Suess et al, 2010;Thai et al, 2014;To, Chan, et al, 2010;To, Hung, et al, 2010;Watanabe, Nukuzuma, Ito, & Ihara, 2011;Wu, Wang, Chen, & Chang, 2012;Yang, Lo, Ho, Wu, & Liu, 2011) and data were collected from each study. For preprinted studies that were published as journal articles before the revised submission of this manuscript, we included the citation for the journal article.…”

Section: Med and Bmj)mentioning

confidence: 99%

Heterogeneity in transmissibility and shedding SARS-CoV-2 via droplets and aerosols

Chen

Bobrovitz

Premji

et al. 2021

eLife

133

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Background: Which virological factors mediate overdispersion in the transmissibility of emerging viruses remains a longstanding question in infectious disease epidemiology.Methods: Here, we use systematic review to develop a comprehensive dataset of respiratory viral loads (rVLs) of SARS-CoV-2, SARS-CoV-1 and influenza A(H1N1)pdm09. We then comparatively meta-analyze the data and model individual infectiousness by shedding viable virus via respiratory droplets and aerosols.Results: The analyses indicate heterogeneity in rVL as an intrinsic virological factor facilitating greater overdispersion for SARS-CoV-2 in the COVID-19 pandemic than A(H1N1)pdm09 in the 2009 influenza pandemic. For COVID-19, case heterogeneity remains broad throughout the infectious period, including for pediatric and asymptomatic infections. Hence, many COVID-19 cases inherently present minimal transmission risk, whereas highly infectious individuals shed tens to thousands of SARS-CoV-2 virions/min via droplets and aerosols while breathing, talking and singing. Coughing increases the contagiousness, especially in close contact, of symptomatic cases relative to asymptomatic ones. Infectiousness tends to be elevated between 1-5 days post-symptom onset.Conclusions: Intrinsic case variation in rVL facilitates overdispersion in the transmissibility of emerging respiratory viruses. Our findings present considerations for disease control in the COVID-19 pandemic as well as future outbreaks of novel viruses.Funding: Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, NSERC Senior Industrial Research Chair program and the Toronto COVID-19 Action Fund.

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Influenza A(H1N1)pdm09 infection and viral load analysis in patients with different clinical presentations

Cited by 17 publications

References 14 publications

Detection of influenza virus in air samples of patient rooms

Detection of influenza virus in air samples of patient rooms

Implications in the quantitation of SARS-CoV2 copies in concurrent nasopharyngeal swabs, whole mouth fluid and respiratory droplets

Heterogeneity in transmissibility and shedding SARS-CoV-2 via droplets and aerosols

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