scholarly journals Estimating the duration of seropositivity of human seasonal coronaviruses using seroprevalence studies

2021 ◽  
Vol 6 ◽  
pp. 138
Author(s):  
Eleanor M. Rees ◽  
Naomi R. Waterlow ◽  
Rachel Lowe ◽  
Adam J. Kucharski ◽  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Young Children ◽  
Credible Interval ◽  
Older Children ◽  
Force Of Infection ◽  
Antibody Persistence ◽  
Seroprevalence Data ◽  
Age Structured ◽  
Human Coronaviruses

Background: The duration of immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still uncertain, but it is of key clinical and epidemiological importance. Seasonal human coronaviruses (HCoV) have been circulating for longer and, therefore, may offer insights into the long-term dynamics of reinfection for such viruses. Methods: Combining historical seroprevalence data from five studies covering the four circulating HCoVs with an age-structured reverse catalytic model, we estimated the likely duration of seropositivity following seroconversion. Results: We estimated that antibody persistence lasted between 0.9 (95% Credible interval: 0.6 - 1.6) and 3.8 (95% CrI: 2.0 - 7.4) years. Furthermore, we found the force of infection in older children and adults (those over 8.5 [95% CrI: 7.5 - 9.9] years) to be higher compared with young children in the majority of studies. Conclusions: These estimates of endemic HCoV dynamics could provide an indication of the future long-term infection and reinfection patterns of SARS-CoV-2.

scholarly journals Estimating the duration of seropositivity of human seasonal coronaviruses using seroprevalence studies

2021 ◽  
Vol 6 ◽  
pp. 138
Author(s):  
Eleanor M. Rees ◽  
Naomi R. Waterlow ◽  
Rachel Lowe ◽  
Adam J. Kucharski ◽  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Young Children ◽  
Credible Interval ◽  
Older Children ◽  
Force Of Infection ◽  
Antibody Persistence ◽  
Seroprevalence Data ◽  
Age Structured ◽  
Human Coronaviruses

Background: The duration of immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still uncertain, but it is of key clinical and epidemiological importance. Seasonal human coronaviruses (HCoV) have been circulating for longer and, therefore, may offer insights into the long-term dynamics of reinfection for such viruses. Methods: Combining historical seroprevalence data from five studies covering the four circulating HCoVs with an age-structured reverse catalytic model, we estimated the likely duration of seropositivity following seroconversion. Results: We estimated that antibody persistence lasted between 0.9 (95% Credible interval: 0.6 - 1.6) and 3.8 (95% CrI: 2.0 - 7.4) years. Furthermore, we found the force of infection in older children and adults (those over 8.5 [95% CrI: 7.5 - 9.9] years) to be higher compared with young children in the majority of studies. Conclusions: These estimates of endemic HCoV dynamics could provide an indication of the future long-term infection and reinfection patterns of SARS-CoV-2.

scholarly journals Estimating the duration of seropositivity of human seasonal coronaviruses using seroprevalence studies

2021 ◽  
Vol 6 ◽  
pp. 138
Author(s):  
Eleanor M. Rees ◽  
Naomi R. Waterlow ◽  
Rachel Lowe ◽  
Adam J. Kucharski ◽  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Young Children ◽  
Credible Interval ◽  
Older Children ◽  
Force Of Infection ◽  
Antibody Persistence ◽  
Seroprevalence Data ◽  
Age Structured ◽  
Human Coronaviruses

Background: The duration of immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still uncertain, but it is of key clinical and epidemiological importance. Seasonal human coronaviruses (HCoV) have been circulating for longer and, therefore, may offer insights into the long-term dynamics of reinfection for such viruses. Methods: Combining historical seroprevalence data from five studies covering the four circulating HCoVs with an age-structured reverse catalytic model, we estimated the likely duration of seropositivity following seroconversion. Results: We estimated that antibody persistence lasted between 0.9 (95% Credible interval: 0.6 - 1.6) and 3.8 (95% CrI: 2.0 - 7.4) years. Furthermore, we found the force of infection in older children and adults (those over 8.5 [95% CrI: 7.5 - 9.9] years) to be higher compared with young children in the majority of studies. Conclusions: These estimates of endemic HCoV dynamics could provide an indication of the future long-term infection and reinfection patterns of SARS-CoV-2.

scholarly journals Rampant C→U Hypermutation in the Genomes of SARS-CoV-2 and Other Coronaviruses: Causes and Consequences for Their Short- and Long-Term Evolutionary Trajectories

mSphere ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
P. Simmonds
Keyword(s):  
Amino Acid ◽  
Severe Acute Respiratory Syndrome ◽  
Molecular Epidemiology ◽  
Substitution Rate ◽  
Directional Asymmetry ◽  
Sequence Change ◽  
Short And Long Term ◽  
Standard Models ◽  
Human Coronaviruses

ABSTRACT The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has motivated an intensive analysis of its molecular epidemiology following its worldwide spread. To understand the early evolutionary events following its emergence, a data set of 985 complete SARS-CoV-2 sequences was assembled. Variants showed a mean of 5.5 to 9.5 nucleotide differences from each other, consistent with a midrange coronavirus substitution rate of 3 × 10−4 substitutions/site/year. Almost one-half of sequence changes were C→U transitions, with an 8-fold base frequency normalized directional asymmetry between C→U and U→C substitutions. Elevated ratios were observed in other recently emerged coronaviruses (SARS-CoV, Middle East respiratory syndrome [MERS]-CoV), and decreasing ratios were observed in other human coronaviruses (HCoV-NL63, -OC43, -229E, and -HKU1) proportionate to their increasing divergence. C→U transitions underpinned almost one-half of the amino acid differences between SARS-CoV-2 variants and occurred preferentially in both 5′ U/A and 3′ U/A flanking sequence contexts comparable to favored motifs of human APOBEC3 proteins. Marked base asymmetries observed in nonpandemic human coronaviruses (U ≫ A > G ≫ C) and low G+C contents may represent long-term effects of prolonged C→U hypermutation in their hosts. The evidence that much of sequence change in SARS-CoV-2 and other coronaviruses may be driven by a host APOBEC-like editing process has profound implications for understanding their short- and long-term evolution. Repeated cycles of mutation and reversion in favored mutational hot spots and the widespread occurrence of amino acid changes with no adaptive value for the virus represent a quite different paradigm of virus sequence change from neutral and Darwinian evolutionary frameworks and are not incorporated by standard models used in molecular epidemiology investigations. IMPORTANCE The wealth of accurately curated sequence data for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), its long genome, and its low substitution rate provides a relatively blank canvas with which to investigate effects of mutational and editing processes imposed by the host cell. The finding that a large proportion of sequence change in SARS-CoV-2 in the initial months of the pandemic comprised C→U mutations in a host APOBEC-like context provides evidence for a potent host-driven antiviral editing mechanism against coronaviruses more often associated with antiretroviral defense. In evolutionary terms, the contribution of biased, convergent, and context-dependent mutations to sequence change in SARS-CoV-2 is substantial, and these processes are not incorporated by standard models used in molecular epidemiology investigations.

scholarly journals A 10-Year Immunopersistence Study of Hepatitis E Antibodies in Rural Bangladesh

2018 ◽  
Vol 187 (7) ◽  
pp. 1501-1510 ◽  
Author(s):  
Brittany L Kmush ◽  
Khalequ Zaman ◽  
Mohammed Yunus ◽  
Parimalendu Saha ◽  
Kenrad E Nelson ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Hepatitis E ◽  
Population Based ◽  
Cross Sectional ◽  
Rural Bangladesh ◽  
Antibody Persistence ◽  
Seroprevalence Data ◽  
Insight Into

Abstract Hepatitis E virus (HEV) is a major cause of acute viral hepatitis in Southeast Asia. Several studies have suggested that antibody persistence after HEV infection may be transient, possibly increasing the risk of reinfection and contributing to the frequency of outbreaks in HEV-endemic regions. The specific conditions under which antibodies to HEV are lost, or “seroreversion” occurs, are poorly understood. Here, 100 participants from population-based studies in rural Bangladesh were revisited in 2015, 10 years after a documented HEV infection, to examine long-term antibody persistence. Twenty percent (95% confidence interval: 12.0, 28.0) of the participants no longer had detectable antibodies at follow-up, suggesting that antibodies generally persist for at least a decade after infection in rural Bangladesh. Persons who were seronegative at follow-up were generally younger at infection than those who remained positive (14.4 years vs. 33.6 years; P < 0.0001). This age-dependent antibody loss could partially explain cross-sectional seroprevalence data from Southeast Asia, where children have reportedly low antibody prevalence. The results of this study provide new insight into the immunological persistence of HEV infection in a micronutrient-deficient rural population of South Asia, highlighting the importance of age at infection in the ability to produce long-lasting antibodies against HEV.

scholarly journals Long-term antibody persistence study (3 years after last dose) of the 7-valent pneumococcal conjugate vaccine in young children in China

Vaccine ◽  
2016 ◽  
Vol 34 (44) ◽  
pp. 5359-5365 ◽  
Author(s):  
Rongcheng Li ◽  
Kong-Xiong Fang ◽  
Mariano Young ◽  
Xin Zhou ◽  
Zhangjing Chen ◽  
...  
Keyword(s):  
Young Children ◽  
Conjugate Vaccine ◽  
Pneumococcal Conjugate Vaccine ◽  
Antibody Persistence

scholarly journals SARS-CoV-2 infection in households with and without young children: Nationwide cohort study

2021 ◽  
Author(s):  
Anders Husby ◽  
Giulia Corn ◽  
Tyra Grove Krause
Keyword(s):  
Cohort Study ◽  
Young Children ◽  
Cox Regression ◽  
Immunological Response ◽  
Sensitivity Analyses ◽  
Older Children ◽  
Adult Age ◽  
Number Of Children ◽  
Household Members ◽  
Human Coronaviruses

ABSTRACTBackgroundInfections with seasonally spreading human coronaviruses (HCoVs) are common among young children during winter months in the northern hemisphere, with immunological response lasting around a year. However, it is not clear whether recent household exposure to HCoVs reduces the risk of SARS-CoV-2 infection.MethodsIn a nationwide cohort study we followed all adults in Denmark aged 18 to 60 years from February 27 to November 15, 2020. Hazard ratios of SARS-CoV-2 infection by number of young children aged ten months to five years living in the household were estimated using Cox regression adjusted for adult age, gender, and other potential confounders. In sensitivity analyses we investigated the effect of age of children in the household, number of children living outside of the household, and number of other adult household-members.ResultsAmong 449,915 adults in Denmark living in households with young children, 5,761 were tested positive for SARS-CoV-2, while among 2,629,821 adults without young children in their household, 33,788 were tested positive for SARS-CoV-2 (adjusted hazard ratio, 1.05; 95% confidence interval, 1.02 to 1.09). Sensitivity analyses of age of children in the household, number of children living outside of the household, and number of additional adult household members found increasing number of children, and especially increasing number of older children, to substantially increase the risk of SARS-CoV-2 infection.ConclusionsLiving in a household with young children was not associated with decreased risk of SARS-CoV-2 infection, thereby suggesting no strong preventive effect of recent exposure to HCoVs against SARS-CoV-2 infection.

scholarly journals The kinetic variations of anti-nucleocapsid antibody in SARS-CoV-2 infection

2021 ◽  
Author(s):  
Shoji Kawada ◽  
Atsushi Ogata ◽  
Yasuhiro Kato ◽  
Masashi Okamoto ◽  
Yuta Yamaguchi ◽  
...  
Keyword(s):  
Immune Response ◽  
Severe Acute Respiratory Syndrome ◽  
Antibody Response ◽  
Nucleocapsid Protein ◽  
Healthcare Workers ◽  
Humoral Immune ◽  
Antibody Persistence ◽  
Decay Pattern ◽  
Kinetics Of

AbstractThe humoral immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays a pivotal role in controlling coronavirus disease 2019 (COVID-19) infections. However, little is known about the persistence of the antibody response.We evaluated that the kinetics of anti-nucleocapsid protein antibody of SARS-CoV2 infected healthcare workers in COVID-19 cluster occurred hospital. The long-term kinetics of anti-N antibody was classified high and keep pattern, high and decay pattern, and low and keep pattern. COVID-19 contact and symptomaticity was not related to kinetic patterns.The reason of kinetic difference was still unclear. However natural anti-SARS-CoV-2 antibody persistence was not uniform, suggesting inter-individual difference of SARS-CoV2 vaccine efficacy.

Instruction Helps and Hinders Young Children’s Feature Learning

2018 ◽  
Author(s):  
Charles Kalish ◽  
Nigel Noll
Keyword(s):  
Young Children ◽  
Feature Learning ◽  
Irrelevant Information ◽  
Diagnostic Feature ◽  
Older Children ◽  
Prediction Task ◽  
Feature Correlation ◽  
The Future

Existing research suggests that adults and older children experience a tradeoff where instruction and feedback help them solve a problem efficiently, but lead them to ignore currently irrelevant information that might be useful in the future. It is unclear whether young children experience the same tradeoff. Eighty-seven children (ages five- to eight-years) and 42 adults participated in supervised feature prediction tasks either with or without an instructional hint. Follow-up tasks assessed learning of feature correlations and feature frequencies. Younger children tended to learn frequencies of both relevant and irrelevant features without instruction, but not the diagnostic feature correlation needed for the prediction task. With instruction, younger children did learn the diagnostic feature correlation, but then failed to learn the frequencies of irrelevant features. Instruction helped older children learn the correlation without limiting attention to frequencies. Adults learned the diagnostic correlation even without instruction, but with instruction no longer learned about irrelevant frequencies. These results indicate that young children do show some costs of learning with instruction characteristic of older children and adults. However, they also receive some of the benefits. The current study illustrates just what those tradeoffs might be, and how they might change over development.

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