Quantification and determinants of the amount of respiratory syncytial virus (RSV) shed using real time PCR data from a longitudinal household study

Abstract

A better understanding of respiratory syncytial virus (RSV) Background epidemiology requires realistic estimates of RSV shedding patterns, quantities shed, and identification of the related underlying factors.: RSV infection data arise from a cohort study of 47 households with Methods 493 occupants, in coastal Kenya, during the 2009/2010 RSV season. Nasopharyngeal swabs were taken every 3 to 4 days and screened for RSV using a real time polymerase chain reaction (PCR) assay. The amount of virus shed was quantified by calculating the 'area under the curve' using the trapezoidal rule applied to rescaled PCR cycle threshold output. Multivariable linear regression was used to identify correlates of amount of virus shed.: The median quantity of virus shed per infection episode was 29.4 Results (95% CI: 15.2, 54.2) log ribonucleic acid (RNA) copies * days. Young age (<1 year), presence of upper respiratory symptoms, intra-household acquisition of infection, an individual's first infection episode in the RSV season, and having a co-infection of RSV group A and B were associated with increased amount of virus shed.: The findings provide insight into which groups of individuals Conclusions have higher potential for transmission, information which may be useful in designing RSV prevention strategies. Keywords Amendments from Version 1Differences between versions 1 and 2 of the article 'Quantification and determinants of the amount of respiratory syncytial virus (RSV) shed using real time PCR data from a longitudinal household study'.Version two of this article;1. Emphasizes that log transformed values are used for the viral densities and AUC values and why they are used. The reasons for this are given as being that the log transformed values have a smaller variance and they are less skewed. They are also more suitable for the linear regression analysis. 2. States that the reason sex is adjusted for in the final linear regression model despite not being statistically significant is because it was chosen a priori as an important factor for RSV infections.3. Includes additional information in Table 1 on the total number of individuals per category among all the individuals who took part in the study. 4. Adds a possible explanation as to why individuals who were living with smokers appeared to shed less virus than those who were not living with smokers. Some of the reasons stated are that there were very few individuals in the study who lived with smokers, and we do not have information on the contact patterns of individuals with the smokers. 5. Adds that we tried two different approaches in calculating the AUC. The first involved taking logs of the viral densities and calculating the AUC. The second involved calculating the AUC using untransformed viral densities, then taking logarithms of the AUC. These two approaches did not give substantially different results.

Targeted antiviral treatment using non-ionizing radiation therapy for SARS-CoV-2 and viral pandemics preparedness: Technique, methods and practical notes for clinical application

“…Thus, a simultaneous 10-17 GHz irradiation can provide 38% inactivation for~15 minutes exposure at 1.5 ± 0.4 W/m 2 (24 ± 3 V/m) threshold power density; and 100% inactivation for~15 minutes exposure at 14.5 ± 1 W/m 2 (74 ± 3 V/m) power density. Clinical viral densities inside patients are estimated using the equation y = -3.308x + 42.9 [34]; wherein x and y denote log 10 RNA equivalents (i.e. log 10 number of particles) and throat swab Ct values [5] respectively.…”

“…The equation y = -3.308x + 42.9 [34]; provides a relation between log 10 number of virus particles and clinical throat swab Ct values represented by x and y respectively. Patient-specific exposure durations of~15x minutes can be derived for providing 100% inactivation of SARS-CoV-2 virus particles by 10-17 GHz simultaneous irradiations at 14.5 ± 1 W/m 2 .…”

“…308x + 42 . 9 [ 34 ]; wherein x and y denote log 10 RNA equivalents (i.e. log 10 number of particles) and throat swab Ct values [ 5 ] respectively.…”

Risk factors and patterns of household clusters of respiratory viruses in rural Nepal

“…Over half of RSV infections in children 5–15 years in that study were asymptomatic, with a smaller proportion of asymptomatic infections in infants under 1 year and children 1–4 years at 9% and 17%, respectively [28]. However, they also reported viral shedding in symptomatic RSV infections was 14 log 10 RNA copies greater than in asymptomatic RSV cases suggesting that symptomatic episodes are more likely to transmit virus [29]. Last, we collected weekly specimens and our findings may be biased if non-infant younger children had longer shedding duration compared to older children.…”

“…Viral coinfection with RSV infection has been demonstrated to increase RSV viral load and shedding duration. However, this has not been consistently seen, including a study analysing seven respiratory viruses [29 31, 34]. Finally, electricity in the household, a proxy for socio-economic status and housing conditions, was negatively associated with transmission.…”