Longitudinal Study of Influenza Molecular Viral Shedding in Hutterite Communities

Loeb, Mark; Singh, Pratichi; Fox, Julie D.; Russell, Margaret L.; Pabbaraju, Kanti; Zarra, Danielle; Wong, Sallene; Neupane, Binod; Singh, Pardeep; Webby, Richard J.; Fonseca, Kevin

doi:10.1093/infdis/jis450

Cited by 63 publications

(75 citation statements)

References 32 publications

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“…What this study adds is the additional information of the comprehensive burden of all‐influenza cases in primary care, be they mild or more severe, not only by age, but also by type/subtype, over a long time period. It is interesting that the “typical” pattern of influenza B shows a substantially higher relative iMAARI attack rate among school‐age children5, 6, 7, 8, 9, 10, 11, 12, 13, 14 compared to that in age group 0‐4 (Figure 5, right panel), although in absolute terms the attack rate among 5‐ to 14‐year‐old children is comparable to that caused by A(H3N2). This striking characteristic of influenza B concurs with data from two serological studies, one from the Netherlands and one from Germany, which investigated the seroprevalence of antibodies against influenza virus types and subtypes by year of age among children 17, 18.…”

Section: Discussionmentioning

confidence: 96%

“…Similarly, in the three seasons following the pandemic, influenza‐associated consultations by patients with ILI were estimated in a population‐based surveillance project in 13 US health jurisdictions as 0.7%, 0.2% and 1.1% 16. Given that only between 30% and 80% of all influenza cases manifest themselves as ILI5, 6, 7, 8 and in the same year influenza seasons may be quite different in different countries, the estimated 2.6%, 1.0% and 8.9% in our study lie in a comparable magnitude as the US data. We believe that our combination of surveillance (using ARI data) followed by modelling estimates the population impact of influenza more realistically than sentinel systems that use ILI data.…”

Section: Discussionmentioning

confidence: 99%

“…As a result, ILI case definitions are more specific, but less sensitive compared to ARI, and as a corollary surveillance systems using ILI see more pronounced illness waves and peaks during influenza epidemics. However, because only a portion of all symptomatic influenza cases are captured by ILI case definitions,1, 5, 6, 7, 8, 9 ILI surveillance systems are less well suited to describe and capture the burden of disease of influenza.…”

Section: Introductionmentioning

confidence: 99%

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Estimation of influenza‐attributable medically attended acute respiratory illness by influenza type/subtype and age, Germany, 2001/02–2014/15

Heiden

Buchholz

2016

Influenza Resp Viruses

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BackgroundThe total burden of influenza in primary care is difficult to assess. The case definition of medically attended “acute respiratory infection” (MAARI) in the German physician sentinel is sensitive; however, it requires modelling techniques to derive estimates of disease attributable to influenza. We aimed to examine the impact of type/subtype and age.MethodsData on MAARI and virological results of respiratory samples (virological sentinel) were available from 2001/02 until 2014/15. We constructed a generalized additive regression model for the periodic baseline and the secular trend. The weekly number of influenza‐positive samples represented influenza activity. In a second step, we distributed the estimated influenza‐attributable MAARI (iMAARI) according to the distribution of types/subtypes in the virological sentinel.ResultsSeason‐specific iMAARI ranged from 0.7% to 8.9% of the population. Seasons with the strongest impact were dominated by A(H3), and iMAARI attack rate of the pandemic 2009 (A(H1)pdm09) was 4.9%. Regularly the two child age groups (0‐4 and 5‐14 years old) had the highest iMAARI attack rates reaching frequently levels up to 15%‐20%. Influenza B affected the age group of 5‐ to 14‐year‐old children substantially more than any other age group. Sensitivity analyses demonstrated both comparability and stability of the model.ConclusionWe constructed a model that is well suited to estimate the substantial impact of influenza on the primary care sector. A(H3) causes overall the greatest number of iMAARI, and influenza B has the greatest impact on school‐age children. The model may incorporate time series of other pathogens as they become available.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Estimation of influenza‐attributable medically attended acute respiratory illness by influenza type/subtype and age, Germany, 2001/02–2014/15

Heiden

Buchholz

2016

Influenza Resp Viruses

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“…As a consequence, if a good biomarker of infectivity is available, it might be advantageous simply to study the biomarker in a sample of influenza case patients, without having to follow up contacts of those patients. Viral shedding seems a natural candidate and has indeed been used as a proxy measure of infectivity in many studies [3][4][5][6][7][8][9][10][11]. One common approach is to use the duration of viral shedding as the infectious period.…”

mentioning

confidence: 99%

“…One common approach is to use the duration of viral shedding as the infectious period. This leads to estimates of the average infectious period in the range of 4-8 days [3][4][5][6][7][8][9][10][11]. However, this estimate does not take into account the major variations in viral loads that occur over time and may affect infectivity.…”

mentioning

confidence: 99%

Influenza A Virus Shedding and Infectivity in Households

Tsang¹,

Cowling²,

Fang³

et al. 2015

J Infect Dis.

109

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Background. Viral shedding is often considered to correlate with the infectivity of influenza, but the evidence for this is limited.Methods. In a detailed study of influenza virus transmission within households in 2008-2012, index case patients with confirmed influenza were identified in outpatient clinics, and we collected nose and throat swab specimens for testing by reverse-transcription polymerase chain reaction from all household members regardless of illness. We used individual-based hazard models to characterize the relationship between viral load (V ) and infectivity.Results. Assuming that infectivity was proportional to viral load V gave the worst fit, because it strongly overestimated the proportion of transmission occurring at symptom onset. Alternative models assuming that infectivity was proportional to a various functions of V provided better fits, although they all overestimated the proportion of transmission occurring >3 days after symptom onset. The best fitting model assumed that infectivity was proportion to V γ , with estimates of γ = 0.136 and γ = 0.156 for seasonal influenza A(H1N1) and A(H3N2) respectively.Conclusions. All the models we considered that used viral loads to approximate infectivity of a case imperfectly explained the timing of influenza secondary infections in households. Identification of more accurate correlates of infectivity will be important to inform control policies and disease modeling.

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Comparison of Clinical and Epidemiological Characteristics of Asymptomatic and Symptomatic SARS-CoV-2 Infection in Children

et al. 2020

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To understand the epidemiological and clinical features of the symptomatic and asymptomatic pediatric cases of COVID-19, we carried out a prospective study in Shanghai during the period of January 19 to April 30, 2020. A total of 49 children (mean age 11.5 ± 5.12 years) confirmed with SARS-CoV-2 infection were enrolled in the study, including 11 (22.4%) domestic cases and 38 (77.6%) imported cases. Nine (81.8%) local cases and 12 (31.6%) imported cases had a definitive epidemiological exposure. Twenty-eight (57.1%) were symptomatic and 21 (42.9%) were asymptomatic. Neither asymptomatic nor symptomatic cases progressed to severe diseases. The mean duration of viral shedding for SARS-CoV-2 in upper respiratory tract was 14.1 ± 6.4 days in asymptomatic cases and 14.8 ± 8.4 days in symptomatic cases ( P > 0.05). Forty-five (91.8%) cases had viral RNA detected in stool. The mean duration of viral shedding in stool was 28.1 ± 13.3 days in asymptomatic cases and 30.8 ± 18.6 days in symptomatic participants ( P > 0.05). Children < 7 years shed viral RNA in stool for a longer duration than school-aged children ( P < 0.05). Forty-three (87.8%) cases had seropositivity for antibodies against SARS-CoV-2 within 1–3 weeks after confirmation with infection. In conclusion, asymptomatic SARS-CoV-2 infection may be common in children in the community during the COVID-19 pandemic wave. Asymptomatic cases shed viral RNA in a similar pattern as symptomatic cases do. It is of particular concern that asymptomatic individuals are potentially seed transmission of SARS-CoV-2 and pose a challenge to disease control.

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Longitudinal Study of Influenza Molecular Viral Shedding in Hutterite Communities

Cited by 63 publications

References 32 publications

Estimation of influenza‐attributable medically attended acute respiratory illness by influenza type/subtype and age, Germany, 2001/02–2014/15

Estimation of influenza‐attributable medically attended acute respiratory illness by influenza type/subtype and age, Germany, 2001/02–2014/15

Influenza A Virus Shedding and Infectivity in Households

Comparison of Clinical and Epidemiological Characteristics of Asymptomatic and Symptomatic SARS-CoV-2 Infection in Children

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