viral kinetics
Recently Published Documents


TOTAL DOCUMENTS

362
(FIVE YEARS 83)

H-INDEX

34
(FIVE YEARS 6)

2021 ◽  
Author(s):  
Ayato Murata ◽  
Kiyohiko Angata ◽  
Maki Sogabe ◽  
Shunsuke Sato ◽  
Takafumi Ichida ◽  
...  

Abstract Serum hepatitis B surface antigen (HBsAg) is a component of hepatitis B virus (HBV) virions and non-infectious subviral particles (SVPs). O-glycosylation of the PreS2 domain of middle HBsAg protein is a distinct characteristic of genotype C HBV virions versus SVPs. We measured serum O-glycosylated HBsAg levels in 47 treatment-naïve patients with genotype C chronic hepatitis B (CHB) at baseline and after 48 weeks of nucleos(t)ide analog (NA) therapy by immunoassay using a monoclonal antibody against the O-glycosylated PreS2 domain of middle HBsAg, and analyzed their correlations with conventional HBV marker levels. At baseline, serum O-glycosylated HBsAg levels were significantly correlated with HBV DNA, HBsAg, and hepatitis B-core related antigen (HBcrAg) levels. HBV DNA and O-glycosylated HBsAg levels were decreased after 48 weeks of NA therapy. The correlation between O-glycosylated HBsAg and HBsAg or HBcrAg levels was lost in patients who achieved undetectable HBV DNA. HBV DNA and RNA were detected in the O-glycosylated HBsAg-binding serum fraction, and the proportion of HBV RNA increased during NA therapy. In conclusion, serum O-glycosylated HBsAg levels change during NA therapy and may reflect combined serum HBV DNA and RNA virion levels, and an O-glycosylated HBsAg-based immunoassay may allow monitoring viral kinetics during NA therapy.


2021 ◽  
Vol 118 (49) ◽  
pp. e2111477118
Author(s):  
Ruian Ke ◽  
Carolin Zitzmann ◽  
David D. Ho ◽  
Ruy M. Ribeiro ◽  
Alan S. Perelson

The within-host viral kinetics of SARS-CoV-2 infection and how they relate to a person’s infectiousness are not well understood. This limits our ability to quantify the impact of interventions on viral transmission. Here, we develop viral dynamic models of SARS-CoV-2 infection and fit them to data to estimate key within-host parameters such as the infected cell half-life and the within-host reproductive number. We then develop a model linking viral load (VL) to infectiousness and show a person’s infectiousness increases sublinearly with VL and that the logarithm of the VL in the upper respiratory tract is a better surrogate of infectiousness than the VL itself. Using data on VL and the predicted infectiousness, we further incorporated data on antigen and RT-PCR tests and compared their usefulness in detecting infection and preventing transmission. We found that RT-PCR tests perform better than antigen tests assuming equal testing frequency; however, more frequent antigen testing may perform equally well with RT-PCR tests at a lower cost but with many more false-negative tests. Overall, our models provide a quantitative framework for inferring the impact of therapeutics and vaccines that lower VL on the infectiousness of individuals and for evaluating rapid testing strategies.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hui Long ◽  
Jing Zhao ◽  
Hao-Long Zeng ◽  
Qing-Bin Lu ◽  
Li-Qun Fang ◽  
...  

Abstract Background The temporal relationship between SARS-CoV-2 and antibody production and clinical progression remained obscure. The aim of this study was to describe the viral kinetics of symptomatic patients with SARS-CoV-2 infection and identify factors that might contribute to prolonged viral shedding. Methods Symptomatic COVID-19 patients were enrolled in two hospitals in Wuhan, China, from whom the respiratory samples were collected and measured for viral loads consecutively by reverse transcriptase quantitative PCR (RT-qPCR) assay. The viral shedding pattern was delineated in relate to the epidemiologic and clinical information. Results Totally 2726 respiratory samples collected from 703 patients were quantified. The SARS-CoV-2 viral loads were at the highest level during the initial stage after symptom onset, which subsequently declined with time. The median time to SARS-CoV-2 negativity of nasopharyngeal test was 28 days, significantly longer in patients with older age (> 60 years old), female gender and those having longer interval from symptom onset to hospital admission (> 10 days). The multivariate Cox regression model revealed significant effect from older age (HR 0.73, 95% CI 0.55–0.96), female gender (HR 0.72, 95% CI 0.55–0.96) and longer interval from symptom onset to admission (HR 0.44, 95% CI 0.33–0.59) on longer time to SARS-CoV-2 negativity. The IgM antibody titer was significantly higher in the low viral loads group at 41–60 days after symptom onset. At the population level, the average viral loads were higher in early than in late outbreak periods. Conclusions The prolonged viral shedding of SARS-CoV-2 was observed in COVID-19 patients, particularly in older, female and those with longer interval from symptom onset to admission.


2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Thalia Rodriguez ◽  
Hana M. Dobrovolny

The SARS-CoV-2 virus disproportionately causes serious illness and death in older individuals. In order to have the greatest impact in decreasing the human toll caused by the virus, antiviral treatment should be targeted to older patients. For this, we need a better understanding of the differences in viral dynamics between SARS-CoV-2 infection in younger and older adults. In this study, we use previously published averaged viral titre measurements from the nose and throat of SARS-CoV-2 infection in young and aged cynomolgus macaques to parametrize a viral kinetics model. We find that all viral kinetics parameters differ between young and aged macaques in the nasal passages, but that there are fewer differences in parameter estimates from the throat. We further use our parametrized model to study the antiviral treatment of young and aged animals, finding that early antiviral treatment is more likely to lead to a lengthening of the infection in aged animals, but not in young animals.


Author(s):  
Da Young Kim ◽  
Eun Kyung Bae ◽  
Jun-Won Seo ◽  
Na Ra Yun ◽  
Choon-Mee Kim ◽  
...  

In our study, we analyzed the viral kinetics of COVID-19 patients. Our study reveals differences in viral shedding according to the severity of disease in COVID-19 patients. Viral shedding had a longer duration in severely affected patients, and the cyclic threshold values were lower in the group receiving steroids. This study is expected to be helpful in analyzing the trend of the disease course according to steroid use and severity of SARS-COV-2 disease.


2021 ◽  
Vol 40 ◽  
pp. 101129
Author(s):  
Yaping Wang ◽  
Ruchong Chen ◽  
Fengyu Hu ◽  
Yun Lan ◽  
Zhaowei Yang ◽  
...  

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1921
Author(s):  
David A. Swan ◽  
Ashish Goyal ◽  
Chloe Bracis ◽  
Mia Moore ◽  
Elizabeth Krantz ◽  
...  

SARS-CoV-2 vaccine clinical trials assess efficacy against disease (VEDIS), the ability to block symptomatic COVID-19. They only partially discriminate whether VEDIS is mediated by preventing infection completely, which is defined as detection of virus in the airways (VESUSC), or by preventing symptoms despite infection (VESYMP). Vaccine efficacy against transmissibility given infection (VEINF), the decrease in secondary transmissions from infected vaccine recipients, is also not measured. Using mathematical modeling of data from King County Washington, we demonstrate that if the Moderna (mRNA-1273QS) and Pfizer-BioNTech (BNT162b2) vaccines, which demonstrated VEDIS > 90% in clinical trials, mediate VEDIS by VESUSC, then a limited fourth epidemic wave of infections with the highly infectious B.1.1.7 variant would have been predicted in spring 2021 assuming rapid vaccine roll out. If high VEDIS is explained by VESYMP, then high VEINF would have also been necessary to limit the extent of this fourth wave. Vaccines which completely protect against infection or secondary transmission also substantially lower the number of people who must be vaccinated before the herd immunity threshold is reached. The limited extent of the fourth wave suggests that the vaccines have either high VESUSC or both high VESYMP and high VEINF against B.1.1.7. Finally, using a separate intra-host mathematical model of viral kinetics, we demonstrate that a 0.6 log vaccine-mediated reduction in average peak viral load might be sufficient to achieve 50% VEINF, which suggests that human challenge studies with a relatively low number of infected participants could be employed to estimate all three vaccine efficacy metrics.


2021 ◽  
Vol 15 (8) ◽  
pp. e0009718
Author(s):  
Rima R. Sahay ◽  
Anita M. Shete ◽  
Pragya D. Yadav ◽  
Savita Patil ◽  
Triparna Majumdar ◽  
...  

Background Thirty-four CCHF cases (17 fatal; 17 survived) were confirmed from Gujarat state, India during the year 2019. We aimed to find out the viral load, antibody kinetics, cytokine profile and phylogenetic analysis between fatal and non- fatal cases. Methods Thirty four cases were included in this study. Blood and urine samples were collected from all the cases on the day of admission to hospital. Non-fatal cases were followed weekly for understanding the profile of viral kinetics, anti-CCHFV IgM and IgG antibodies. We also quantified the cytokines in both fatal and non-fatal cases. For epidemiological correlation, livestock were screened for anti-CCHF IgG antibodies and the tick pool specimens were tested by real time RT-PCR. Virus isolation was attempted on tick pools and human specimens and phylogenetic analysis performed on human and ticks complete genome sequences. Results CCHF cases were detected throughout year in 2019 with the peak in August. Out of 34 cases, eight secondary CCHF cases were reported. Cases were predominantly detected in males and in 19–45 years age group (55.88%). The persistence of viremia was observed till 76th POD (post onset date) in one case whereas anti-CCHFV IgM and IgG was detected amongst these cases from the 2nd and 20th POD respectively. Positivity observed amongst livestock and tick pools were was 21.57% and 7.4% respectively. The cytokine analysis revealed a significant increase in the level of serum IL-6, IL-10 and IFN-γ during the acute phase of the infection, but interestingly IL-10 lowered to normal upon clearance of the virus in the clinically recovered case. Fatal cases had high viral RNA copy numbers. Bleeding from one or two mucosal sites was significantly associated with fatality (OR-16.47;p-0.0034 at 95% CI). We could do CCHF virus isolation from two cases. Phylogenetic analysis revealed circulation of re-assortment of Asian-West African genotypes in humans and ticks. Conclusions The persistence of CCHF viral RNA was detected till 76th POD in one of the survivors. The circulation of a re-assortment Asian-West African genotype in a CCHF case is also reported first time from India.


Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1609
Author(s):  
Megan A. O’Connor ◽  
Paul V. Munson ◽  
Sandra E. Dross ◽  
Hillary C. Tunggal ◽  
Thomas B. Lewis ◽  
...  

Selection of a pre-clinical non-human primate (NHP) model is essential when evaluating therapeutic vaccine and treatment strategies for HIV. SIV and SHIV-infected NHPs exhibit a range of viral burdens, pathologies, and responses to combinatorial antiretroviral therapy (cART) regimens and the choice of the NHP model for AIDS could influence outcomes in studies investigating interventions. Previously, in rhesus macaques (RMs) we showed that maintenance of mucosal Th17/Treg homeostasis during SIV infection correlated with a better virological response to cART. Here, in RMs we compared viral kinetics and dysregulation of gut homeostasis, defined by T cell subset disruption, during highly pathogenic SIVΔB670 compared to SHIV-1157ipd3N4 infection. SHIV infection resulted in lower acute viremia and less disruption to gut CD4 T-cell homeostasis. Additionally, 24/24 SHIV-infected versus 10/19 SIV-infected animals had sustained viral suppression <100 copies/mL of plasma after 5 months of cART. Significantly, the more profound viral suppression during cART in a subset of SIV and all SHIV-infected RMs corresponded with less gut immune dysregulation during acute SIV/SHIV infection, defined by maintenance of the Th17/Treg ratio. These results highlight significant differences in viral control during cART and gut dysregulation in NHP AIDS models and suggest that selection of a model may impact the evaluation of candidate therapeutic interventions for HIV treatment and cure strategies.


Sign in / Sign up

Export Citation Format

Share Document