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1.
J Appl Gerontol ; 43(3): 231-241, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37801694

RESUMEN

Home modification is essential in helping older adults age in place safely and independently. The purpose of this study was to examine the impact of housing location and disability status on home modification projects among older adults using the 2019 American Housing Survey Data. The study found that recent home modification strategies were significantly different according to older adults' housing locations and health status. Older adults in non-metropolitan areas and with disability were less likely to make home modifications, and when they did so, they spent less money on the modifications. The findings highlight the importance of providing adequate home modification programs and resources for home modifications, as well as support and education from community organizations, particularly for older adults in non-metropolitan areas. The results of this study can assist in developing housing policies and guidelines to address these current and future challenges in home modification implementation for the aging population.


Asunto(s)
Personas con Discapacidad , Vivienda , Anciano , Humanos , Envejecimiento , Composición Familiar , Estado de Salud , Estados Unidos , Ambiente en el Hogar
2.
Pediatr Res ; 94(4): 1327-1334, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37173406

RESUMEN

BACKGROUND: Although most children experience mild symptoms during acute SARS-CoV-2 infection, some develop the severe post-COVID-19 complication, Multisystem Inflammatory Syndrome in Children (MIS-C). While acute presentations of COVID-19 and MIS-C have been well immunophenotyped, little is known about the lasting immune profile in children after acute illness. METHODS: Children 2 months-20 years of age presenting with either acute COVID-19 (n = 9) or MIS-C (n = 12) were enrolled in a Pediatric COVID-19 Biorepository at a single medical center. We deeply profiled humoral immune responses and circulating cytokines following pediatric COVID-19 and MIS-C. RESULTS: Twenty-one children and young adults provided blood samples at both acute presentation and 6-month follow-up (mean: 6.5 months; standard deviation: 1.77 months). Pro-inflammatory cytokine elevations resolved after both acute COVID-19 and MIS-C. Humoral profiles continue to mature after acute COVID-19, displaying decreasing IgM and increasing IgG over time, as well as stronger effector functions, including antibody-dependent monocyte activation. In contrast, MIS-C immune signatures, especially anti-Spike IgG1, diminished over time. CONCLUSIONS: Here, we show the mature immune signature after pediatric COVID-19 and MIS-C, displaying resolving inflammation with recalibration of the humoral responses. These humoral profiles highlight immune activation and vulnerabilities over time in these pediatric post-infectious cohorts. IMPACT: The pediatric immune profile matures after both COVID-19 and MIS-C, suggesting a diversified anti-SARS-CoV-2 antibody response after resolution of acute illness. While pro-inflammatory cytokine responses resolve in the months following acute infection in both conditions, antibody-activated responses remain relatively heightened in convalescent COVID-19. These data may inform long-term immunoprotection from reinfection in children with past SARS-CoV-2 infections or MIS-C.


Asunto(s)
COVID-19 , Adulto Joven , Niño , Humanos , COVID-19/diagnóstico , SARS-CoV-2 , Enfermedad Aguda , Síndrome de Respuesta Inflamatoria Sistémica/diagnóstico , Citocinas , Anticuerpos Antivirales
3.
iScience ; 26(5): 106582, 2023 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-37082529

RESUMEN

The number of mutations in the omicron (B.1.1.529) BA.1 variant of concern led to an unprecedented evasion of vaccine induced immunity. However, despite rise in global infections, severe disease did not increase proportionally and is likely linked to persistent recognition of BA.1 by T cells and non-neutralizing opsonophagocytic antibodies. Yet, the emergence of new sublineage BA.2, which is more transmissible than BA.1 despite relatively preserved neutralizing antibody responses, has raised the possibility that BA.2 may evade other vaccine-induced responses. Here, we comprehensively profiled the BNT162b2 vaccine-induced response to several VOCs, including omicron BA.1 and BA.2. While vaccine-induced immune responses were compromised against both omicron sublineages, vaccine-induced antibody isotype titers, and non-neutralizing Fc effector functions were attenuated to the omicron BA.2 spike compared to BA.1. Conversely, FcγR2a and FcγR2b binding was elevated to BA.2, albeit lower than BA.1 responses, potentially contributing to persistent protection against severity of disease.

4.
NPJ Vaccines ; 7(1): 158, 2022 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-36463314

RESUMEN

Currently available mRNA vaccines are extremely safe and effective to prevent severe SARS-CoV-2 infections. However, the emergence of variants of concerns (VOCs) has highlighted the importance of high population-based vaccine rates to effectively suppress viral transmission and breakthrough infections. While initially left out from vaccine efforts, children have become one of the most affected age groups and are key targets to stop community and household spread. Antibodies are central for vaccine-induced protection and emerging data points to the importance of additional Fc effector functions like opsononophagocytosis or cytotoxicity, particularly in the context of VOCs that escape neutralizing antibodies. Here, we observed delayed induction and reduced magnitude of vaccine-induced antibody titers in children 5-11 years receiving two doses of the age-recommended 10 µg dose of the Pfizer SARS-CoV-2 BNT162b2 vaccine compared to adolescents (12-15 years) or adults receiving the 30 µg dose. Conversely, children mounted equivalent or more robust neutralization and opsonophagocytic functions at peak immunogenicity, pointing to a qualitatively more robust humoral functional response in children. Moreover, broad cross-VOC responses were observed across children, with enhanced IgM and parallel IgG cross-reactivity to VOCs in children compared to adults. Collectively, these data argue that despite the lower magnitude of the BNT162b2-induced antibody response in children, vaccine-induced immunity in children target VOCs broadly and exhibit enhanced functionality that may contribute to the attenuation of disease.

5.
Cell ; 185(26): 4873-4886.e10, 2022 12 22.
Artículo en Inglés | MEDLINE | ID: mdl-36513064

RESUMEN

Respiratory syncytial virus (RSV) infection is a major cause of severe lower respiratory tract infection and death in young infants and the elderly. With no effective prophylactic treatment available, current vaccine candidates aim to elicit neutralizing antibodies. However, binding and neutralization have poorly predicted protection in the past, and accumulating data across epidemiologic cohorts and animal models collectively point to a role for additional antibody Fc-effector functions. To begin to define the humoral correlates of immunity against RSV, here we profiled an adenovirus 26 RSV-preF vaccine-induced humoral immune response in a group of healthy adults that were ultimately challenged with RSV. Protection from infection was linked to opsonophagocytic functions, driven by IgA and differentially glycosylated RSV-specific IgG profiles, marking a functional humoral immune signature of protection against RSV. Furthermore, Fc-modified monoclonal antibodies able to selectively recruit effector functions demonstrated significant antiviral control in a murine model of RSV.


Asunto(s)
Infecciones por Virus Sincitial Respiratorio , Virus Sincitial Respiratorio Humano , Ratones , Animales , Infecciones por Virus Sincitial Respiratorio/prevención & control , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Inmunoglobulina G , Fragmentos Fc de Inmunoglobulinas , Proteínas Virales de Fusión
6.
Cell Rep Med ; 3(11): 100811, 2022 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-36351430

RESUMEN

Coronavirus disease 2019 (COVID-19) convalescent plasma (CCP), a passive polyclonal antibody therapeutic agent, has had mixed clinical results. Although antibody neutralization is the predominant approach to benchmarking CCP efficacy, CCP may also influence the evolution of the endogenous antibody response. Using systems serology to comprehensively profile severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) functional antibodies of hospitalized people with COVID-19 enrolled in a randomized controlled trial of CCP (ClinicalTrials.gov: NCT04397757), we find that the clinical benefits of CCP are associated with a shift toward reduced inflammatory Spike (S) responses and enhanced nucleocapsid (N) humoral responses. We find that CCP has the greatest clinical benefit in participants with low pre-existing anti-SARS-CoV-2 antibody function and that CCP-induced immunomodulatory Fc glycan profiles and N immunodominant profiles persist for at least 2 months. We highlight a potential mechanism of action of CCP associated with durable immunomodulation, outline optimal patient characteristics for CCP treatment, and provide guidance for development of a different class of COVID-19 hyperinflammation-targeting antibody therapeutic agents.


Asunto(s)
COVID-19 , Humanos , COVID-19/terapia , SARS-CoV-2 , Inmunización Pasiva/métodos , Anticuerpos Antivirales/uso terapéutico , Nucleocápside , Sueroterapia para COVID-19
7.
Sci Transl Med ; 14(672): eabn9237, 2022 11 23.
Artículo en Inglés | MEDLINE | ID: mdl-35881018

RESUMEN

Although children have been largely spared from coronavirus disease 2019 (COVID-19), the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) with increased transmissibility, combined with fluctuating mask mandates and school reopenings, has led to increased infections and disease among children. Thus, there is an urgent need to roll out COVID-19 vaccines to children of all ages. However, whether children respond equivalently to adults to mRNA vaccines and whether dosing will elicit optimal immunity remain unclear. Here, we aimed to deeply profile the vaccine-induced humoral immune response in 6- to 11-year-old children receiving either a pediatric (50 µg) or adult (100 µg) dose of the mRNA-1273 vaccine and to compare these responses to vaccinated adults, infected children, and children who experienced multisystem inflammatory syndrome in children (MIS-C). Children elicited an IgG-dominant vaccine-induced immune response, surpassing adults at a matched 100-µg dose but more variable immunity at a 50-µg dose. Irrespective of titer, children generated antibodies with enhanced Fc receptor binding capacity. Moreover, like adults, children generated cross-VOC humoral immunity, marked by a decline of omicron-specific receptor binding domain, but robustly preserved omicron spike protein binding. Fc receptor binding capabilities were also preserved in a dose-dependent manner. These data indicate that both the 50- and 100-µg doses of mRNA vaccination in children elicit robust cross-VOC antibody responses and that 100-µg doses in children result in highly preserved omicron-specific functional humoral immunity.


Asunto(s)
Formación de Anticuerpos , Vacunas contra la COVID-19 , COVID-19 , Niño , Humanos , Vacuna nCoV-2019 mRNA-1273 , Anticuerpos Antivirales , COVID-19/prevención & control , Vacunas contra la COVID-19/inmunología , Receptores Fc , SARS-CoV-2 , Vacunación
8.
Am J Obstet Gynecol ; 227(3): 493.e1-493.e7, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35430229

RESUMEN

BACKGROUND: SARS-CoV-2 infection is associated with enhanced disease severity in pregnant women. Despite the potential of COVID-19 vaccines to reduce severe disease, vaccine uptake remained relatively low among pregnant women. Just as coordinated messaging from the Centers for Disease Control and Prevention and leading obstetrics organizations began to increase vaccine confidence in this vulnerable group, the evolution of SARS-CoV-2 variants of concerns, including the Omicron variant, raised new concerns about vaccine efficacy because of their ability to escape vaccine-induced neutralizing antibodies. Early data point to a milder disease course following infection with the Omicron variant in vaccinated individuals. Thus, these data suggest that alternate vaccine-induced immunity beyond neutralization may continue to attenuate Omicron variant-induced disease, such as Fc-mediated antibody activity. OBJECTIVE: This study aimed to test whether vaccine-induced antibodies raised during pregnancy continue to bind to and leverage Fc receptors to protect against variants of concern including the Omicron variant. STUDY DESIGN: The receptor binding domain or whole spike-specific antibody isotype binding titers and Fc gamma receptor binding directed toward variants of concern, including the Omicron variant, were analyzed in pregnant women after receiving the full dose regimen of either the Pfizer/BioNTech BNT62b2 (n=10) or Moderna mRNA-1273 (n=10) vaccination using a multiplexing Luminex assay. RESULTS: Reduced isotype recognition of the Omicron receptor binding domain was observed following administration of either vaccine with relatively preserved, albeit reduced, recognition of the whole Omicron spike by immunoglobulin M and G antibodies. Despite the near complete loss of Fc receptor binding to the Omicron receptor binding domain, Fc receptor binding to the Omicron spike was more variable but largely preserved. CONCLUSION: Reduced binding titers to the Omicron receptor binding domain aligns with the observed loss of neutralizing activity. Despite the loss of neutralization, preserved, albeit reduced, Omicron spike recognition and Fc receptor binding potentially continue to attenuate disease severity in pregnant women.


Asunto(s)
COVID-19 , Complicaciones Infecciosas del Embarazo , Vacunas , Anticuerpos Antivirales , COVID-19/prevención & control , Vacunas contra la COVID-19 , Femenino , Humanos , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Embarazo , Complicaciones Infecciosas del Embarazo/prevención & control , ARN Mensajero , Receptores Fc , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/genética , Vacunación , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/metabolismo
9.
Sci Transl Med ; 14(642): eabn9243, 2022 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-35289637

RESUMEN

The Omicron variant of SARS-CoV-2 has been shown to evade neutralizing antibodies elicited by vaccination or infection. Despite the global spread of the Omicron variant, even among highly vaccinated populations, death rates have not increased concomitantly. These data suggest that immune mechanisms beyond antibody-mediated virus neutralization may protect against severe disease. In addition to neutralizing pathogens, antibodies contribute to control and clearance of infections through Fc effector mechanisms. Here, we probed the ability of vaccine-induced antibodies to drive Fc effector activity against the Omicron variant using samples from individuals receiving one of three SARS-CoV-2 vaccines. Despite a substantial loss of IgM, IgA, and IgG binding to the Omicron variant receptor binding domain (RBD) in samples from individuals receiving BNT162b2, mRNA-1273, and CoronaVac vaccines, stable binding was maintained against the full-length Omicron Spike protein. Compromised RBD binding IgG was accompanied by a loss of RBD-specific antibody Fcγ receptor (FcγR) binding in samples from individuals who received the CoronaVac vaccine, but RBD-specific FcγR2a and FcγR3a binding was preserved in recipients of mRNA vaccines. Conversely, Spike protein-specific antibodies exhibited persistent but reduced binding to FcγRs across all three vaccines, although higher binding was observed in samples from recipients of mRNA vaccines. This was associated with preservation of FcγR2a and FcγR3a binding antibodies and maintenance of Spike protein-specific antibody-dependent natural killer cell activation. Thus, despite the loss of Omicron neutralization, vaccine-induced Spike protein-specific antibodies continue to drive Fc effector functions, suggesting a capacity for extraneutralizing antibodies to contribute to disease control.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Vacuna BNT162 , COVID-19/prevención & control , Humanos , Inmunoglobulina G , ARN Mensajero/genética , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Vacunas de ARNm
10.
Immunity ; 55(2): 355-365.e4, 2022 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-35090580

RESUMEN

SARS-CoV-2 mRNA vaccines confer robust protection against COVID-19, but the emergence of variants has generated concerns regarding the protective efficacy of the currently approved vaccines, which lose neutralizing potency against some variants. Emerging data suggest that antibody functions beyond neutralization may contribute to protection from the disease, but little is known about SARS-CoV-2 antibody effector functions. Here, we profiled the binding and functional capacity of convalescent antibodies and Moderna mRNA-1273 COVID-19 vaccine-induced antibodies across SARS-CoV-2 variants of concern (VOCs). Although the neutralizing responses to VOCs decreased in both groups, the Fc-mediated responses were distinct. In convalescent individuals, although antibodies exhibited robust binding to VOCs, they showed compromised interactions with Fc-receptors. Conversely, vaccine-induced antibodies also bound robustly to VOCs but continued to interact with Fc-receptors and mediate antibody effector functions. These data point to a resilience in the mRNA-vaccine-induced humoral immune response that may continue to offer protection from SARS-CoV-2 VOCs independent of neutralization.


Asunto(s)
Vacuna nCoV-2019 mRNA-1273/inmunología , Anticuerpos Antivirales/inmunología , COVID-19/metabolismo , COVID-19/prevención & control , Receptores Fc/metabolismo , SARS-CoV-2/inmunología , Vacuna nCoV-2019 mRNA-1273/administración & dosificación , Adulto , Anticuerpos Neutralizantes/inmunología , Reacciones Cruzadas/inmunología , Femenino , Interacciones Huésped-Patógeno , Humanos , Masculino , Persona de Mediana Edad , Pruebas de Neutralización , Unión Proteica , Glicoproteína de la Espiga del Coronavirus/inmunología , Vacunación , Adulto Joven
11.
bioRxiv ; 2022 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-35018376

RESUMEN

While children have been largely spared from COVID-19 disease, the emergence of viral variants of concern (VOC) with increased transmissibility, combined with fluctuating mask mandates and school re-openings have led to increased infections and disease among children. Thus, there is an urgent need to roll out COVID-19 vaccines to children of all ages. However, whether children respond equivalently to adults to mRNA vaccines and whether dosing will elicit optimal immunity remains unclear. Given the recent announcement of incomplete immunity induced by the pediatric dose of the BNT162b2 vaccine in young children, here we aimed to deeply profile and compare the vaccine-induced humoral immune response in 6-11 year old children receiving the pediatric (50µg) or adult (100µg) dose of the mRNA-1273 vaccine compared to adults and naturally infected children or children that experienced multi inflammatory syndrome in children (MIS-C) for the first time. Children elicited an IgG dominant vaccine induced immune response, surpassing adults at a matched 100µg dose, but more variable immunity at a 50µg dose. Irrespective of titer, children generated antibodies with enhanced Fc-receptor binding capacity. Moreover, like adults, children generated cross-VOC humoral immunity, marked by a decline of omicron receptor binding domain-binding, but robustly preserved omicron Spike-receptor binding, with robustly preserved Fc-receptor binding capabilities, in a dose dependent manner. These data indicate that while both 50µg and 100µg of mRNA vaccination in children elicits robust cross-VOC antibody responses, 100ug of mRNA in children results in highly preserved omicron-specific functional humoral immunity.

12.
Sci Immunol ; 6(64): eabj2901, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34652962

RESUMEN

The introduction of vaccines has inspired hope in the battle against SARS-CoV-2. However, the emergence of viral variants, in the absence of potent antivirals, has left the world struggling with the uncertain nature of this disease. Antibodies currently represent the strongest correlate of immunity against SARS-CoV-2, thus we profiled the earliest humoral signatures in a large cohort of acutely ill (survivors and nonsurvivors) and mild or asymptomatic individuals with COVID-19. Although a SARS-CoV-2­specific immune response evolved rapidly in survivors of COVID-19, nonsurvivors exhibited blunted and delayed humoral immune evolution, particularly with respect to S2-specific antibodies. Given the conservation of S2 across ß-coronaviruses, we found that the early development of SARS-CoV-2­specific immunity occurred in tandem with preexisting common ß-coronavirus OC43 humoral immunity in survivors, which was also selectively expanded in individuals that develop a paucisymptomatic infection. These data point to the importance of cross-coronavirus immunity as a correlate of protection against COVID-19.


Asunto(s)
COVID-19/inmunología , Reacciones Cruzadas , Inmunidad Humoral , SARS-CoV-2/inmunología , Adolescente , Estudios de Cohortes , Coronavirus Humano OC43/inmunología , Progresión de la Enfermedad , Humanos , Cambio de Clase de Inmunoglobulina , Receptores Fc/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Sobrevivientes , Adulto Joven
13.
bioRxiv ; 2021 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-34013263

RESUMEN

The introduction of vaccines has inspired new hope in the battle against SARS-CoV-2. However, the emergence of viral variants, in the absence of potent antivirals, has left the world struggling with the uncertain nature of this disease. Antibodies currently represent the strongest correlate of immunity against COVID-19, thus we profiled the earliest humoral signatures in a large cohort of severe and asymptomatic COVID-19 individuals. While a SARS-CoV-2-specific immune response evolved rapidly in survivors of COVID-19, non-survivors exhibited blunted and delayed humoral immune evolution, particularly with respect to S2-specific antibody evolution. Given the conservation of S2 across ß-coronaviruses, we found the early development of SARS-CoV-2-specific immunity occurred in tandem with pre-existing common ß-coronavirus OC43 humoral immunity in survivors, which was selectively also expanded in individuals that develop paucisymptomatic infection. These data point to the importance of cross-coronavirus immunity as a correlate of protection against COVID-19.

14.
Nat Med ; 27(3): 454-462, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33589825

RESUMEN

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic continues to spread relentlessly, associated with a high frequency of respiratory failure and mortality. Children experience largely asymptomatic disease, with rare reports of multisystem inflammatory syndrome in children (MIS-C). Identifying immune mechanisms that result in these disparate clinical phenotypes in children could provide critical insights into coronavirus disease 2019 (COVID-19) pathogenesis. Using systems serology, in this study we observed in 25 children with acute mild COVID-19 a functional phagocyte and complement-activating IgG response to SARS-CoV-2, similar to the acute responses generated in adults with mild disease. Conversely, IgA and neutrophil responses were significantly expanded in adults with severe disease. Moreover, weeks after the resolution of SARS-CoV-2 infection, children who develop MIS-C maintained highly inflammatory monocyte-activating SARS-CoV-2 IgG antibodies, distinguishable from acute disease in children but with antibody levels similar to those in convalescent adults. Collectively, these data provide unique insights into the potential mechanisms of IgG and IgA that might underlie differential disease severity as well as unexpected complications in children infected with SARS-CoV-2.


Asunto(s)
Anticuerpos Antivirales/sangre , COVID-19/epidemiología , SARS-CoV-2/inmunología , Adolescente , Adulto , Edad de Inicio , Anciano , Anticuerpos Neutralizantes/análisis , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/análisis , Infecciones Asintomáticas , COVID-19/sangre , COVID-19/patología , Portador Sano/sangre , Portador Sano/epidemiología , Niño , Preescolar , Estudios de Cohortes , Femenino , Humanos , Inmunidad/fisiología , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Pandemias , Índice de Severidad de la Enfermedad , Síndrome de Respuesta Inflamatoria Sistémica/sangre , Síndrome de Respuesta Inflamatoria Sistémica/epidemiología , Adulto Joven
15.
Nat Commun ; 12(1): 1018, 2021 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-33589636

RESUMEN

Antibodies serve as biomarkers of infection, but if sustained can confer long-term immunity. Yet, for most clinically approved vaccines, binding antibody titers only serve as a surrogate of protection. Instead, the ability of vaccine induced antibodies to neutralize or mediate Fc-effector functions is mechanistically linked to protection. While evidence has begun to point to persisting antibody responses among SARS-CoV-2 infected individuals, cases of re-infection have begun to emerge, calling the protective nature of humoral immunity against this highly infectious pathogen into question. Using a community-based surveillance study, we aimed to define the relationship between titers and functional antibody activity to SARS-CoV-2 over time. Here we report significant heterogeneity, but limited decay, across antibody titers amongst 120 identified seroconverters, most of whom had asymptomatic infection. Notably, neutralization, Fc-function, and SARS-CoV-2 specific T cell responses were only observed in subjects that elicited RBD-specific antibody titers above a threshold. The findings point to a switch-like relationship between observed antibody titer and function, where a distinct threshold of activity-defined by the level of antibodies-is required to elicit vigorous humoral and cellular response. This response activity level may be essential for durable protection, potentially explaining why re-infections occur with SARS-CoV-2 and other common coronaviruses.


Asunto(s)
Anticuerpos Antivirales/inmunología , COVID-19/inmunología , SARS-CoV-2/inmunología , Adolescente , Adulto , Anciano , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , COVID-19/sangre , Femenino , Humanos , Inmunidad Humoral/inmunología , Inmunoglobulina G/inmunología , Masculino , Persona de Mediana Edad , Glicoproteína de la Espiga del Coronavirus/inmunología , Linfocitos T/inmunología , Vacunas Virales/inmunología , Adulto Joven
16.
Cyberpsychol Behav ; 9(3): 261-74, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16780394

RESUMEN

This study was designed to understand which factors influence consumer hesitation or delay in online product purchases. The study examined four groups of variables (i.e., consumer characteristics, contextual factors perceived uncertainty factors, and medium/channel innovation factors) that predict three types of online shopping hesitation (i.e., overall hesitation, shopping cart abandonment, and hesitation at the final payment stage). We found that different sets of delay factors are related to different aspects of online shopping hesitation. The study concludes with suggestion for various delay-reduction devices to help consumers close their online decision hesitation.


Asunto(s)
Comercio , Toma de Decisiones , Internet , Humanos , Tiempo de Reacción
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