Persistence of SARS-CoV-2-Specific IgG in Children 6 Months After Infection, Australia.
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ABSTRACT:
SUBMITTER: Toh ZQ
PROVIDER: S-EPMC8314814 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description: Not available
| S-EPMC7833610 | biostudies-literature
Project description:BackgroundThis study evaluates spike protein IgG antibody response following Oxford-AstraZeneca COVID-19 vaccination using the AbC-19™ lateral flow device.MethodsPlasma samples were collected from n = 111 individuals from Northern Ireland. The majority were >50 years old and/or clinically vulnerable. Samples were taken at five timepoints from pre-vaccination until 6-months post-first dose.Results20.3% of participants had detectable IgG responses pre-vaccination, indicating prior COVID-19. Antibodies were detected in 86.9% of participants three weeks after the first vaccine dose, falling to 74.7% immediately prior to the second dose, and rising to 99% three weeks post-second vaccine. At 6-months post-first dose, this decreased to 90.5%. At all timepoints, previously infected participants had significantly higher antibody levels than those not previously infected.ConclusionThis study demonstrates that strong anti-spike protein antibody responses are evoked in almost all individuals that receive two doses of Oxford-AstraZeneca vaccine, and which largely persist beyond six months after first vaccination.
| S-EPMC8900637 | biostudies-literature
Project description:Although some COVID-19 patients maintain SARS-CoV-2-specific serum immunoglobulin G (IgG) for more than 6 months postinfection, others eventually lose IgG levels. We assessed the persistence of SARS-CoV-2-specific B cells in 17 patients, 5 of whom had lost specific IgGs after 5-8 months. Differentiation of blood-derived B cells in vitro revealed persistent SARS-CoV-2-specific IgG B cells in all patients, whereas IgA B cells were maintained in 11. Antibodies derived from cultured B cells blocked binding of viral receptor-binding domain (RBD) to the cellular receptor ACE-2, had neutralizing activity to authentic virus, and recognized the RBD of the variant of concern Alpha similarly to the wild type, whereas reactivity to Beta and Gamma were decreased. Thus, differentiation of memory B cells could be more sensitive for detecting previous infection than measuring serum antibodies. Understanding the persistence of SARS-CoV-2-specific B cells even in the absence of specific serum IgG will help to promote long-term immunity.
| S-EPMC8686444 | biostudies-literature
Project description:ObjectivesWe evaluated the length of time immunocompromised children (ICC) remain positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), identified factors associated with viral persistence, and determined cycle threshold (CT ) values of children with viral persistence as a surrogate of viral load.MethodsWe conducted a retrospective cohort study of ICC at a pediatric hospital from March 2020 to March 2021. Immunocompromised status was defined as primary, secondary, or acquired due to medical comorbidities/immunosuppressive treatment. The primary outcome was time to first of two consecutive negative SARS-CoV-2 polymerase chain reaction (PCR) tests at least 24 hours apart. Testing of sequential clinical specimens from the same subject was conducted using the Centers for Disease Control (CDC) 2019-nCoV real-time reverse transcriptase (RT)-PCR Diagnostic Panel assay. Descriptive statistics, Kaplan-Meier curve median event times and log-rank tests were used to compare outcomes between groups.ResultsNinety-one children met inclusion criteria. Median age was 15.5 years (interquartile range [IQR] 8-18), 64% were male, 58% were White, and 43% were Hispanic/Latinx. Most (67%) were tested in outpatient settings and 58% were asymptomatic. The median time to two negative tests was 42 days (IQR 25.0-55.0), with no differences in median time by illness presentation or level of immunosuppression. Seven children had more than one sample available for repeat testing, and five of seven (71%) children had initial CT values of <30 (moderate to high viral load); four children had CT values of <30, 3-4 weeks later, suggesting persistent moderate to high viral loads.ConclusionsMost ICC with SARS-CoV-2 infection had mild disease, with prolonged viral persistence >6 weeks and moderate to high viral load.
| S-EPMC8661864 | biostudies-literature
Project description:BackgroundMonitoring the adaptive immune responses during the natural course of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection provides useful information for the development of vaccination strategies against this virus and its emerging variants. We thus profiled the serum anti-SARS-CoV-2 antibody levels and specific memory B- and T-cell responses in convalescent coronavirus disease-2019 (COVID-19) patients.MethodsAltogether 119 samples from 88 convalescent donors who experienced mild to critical disease were tested for the presence of elevated anti-spike and anti-receptor binding domain antibody levels over a period of eight months. In addition, level of SARS-CoV-2 neutralizing antibodies, specific memory B- and T-cell responses were tested in a subset of samples.FindingsAnti-SARS-CoV-2 antibodies were present in 85% of the samples collected within 4 weeks after onset of symptoms in COVID-19 patients. Levels of specific IgM/IgA antibodies declined after 1 month while levels of specific IgG antibodies and plasma neutralizing activities remained relatively stable up to 6 months after diagnosis. Anti-SARS-CoV-2 IgG antibodies were still present, though at a significantly lower level, in 80% of the samples collected at 6-8 months after symptom onset. SARS-CoV-2-specific memory B- and T-cell responses developed with time and were persistent in all patients followed up till 6-8 months.ConclusionsOur data suggest that protective adaptive immunity following natural infection of SARS-CoV-2 might persist for at least 6-8 months, regardless of disease severity. Development of medium or long-term protective immunity through vaccination might thus be possible.FundingEU-ATAC consortium, the Italian Ministry of Health and SciLife/KAW.
| S-EPMC7874960 | biostudies-literature
Project description:To evaluate longitudinally the persistence of humoral immunity for up to 6 months in a cohort of hospital employees with mild coronavirus disease 2019 (COVID-19). We measured anti-RBD (receptor binding domain of viral spike protein), anti-N (viral nucleoprotein) and neutralizing antibodies at 1, 3 and 6 months after mostly mild COVID-19 in 200 hospital workers using commercial ELISAs and a surrogate virus neutralization assay. Antibodies specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persisted in all participants for up to 6 months. Anti-RBD geometric mean concentrations (GMCs) progressively increased between months 1 (74.2 U/mL, 95%CI: 62.7-87.8), 3 (103.2 U/mL, 95%CI: 87.9-121.2; p < 0.001), and 6 (123.3 U/mL, 95%CI: 103.4-147.0; p < 0.001) in the whole cohort. Anti-N antibodies were detectable in >97% at all times. Neutralizing antibodies were detectable in 99.5% of participants (195/196) at 6 months post infection. Their GMC progressively decreased between months 1 (20.1 AU/mL, 95%CI: 16.9-24.0), 3 (15.2 AU/mL, 95%CI: 13.2-17.6; p < 0.001) and 6 (9.4 AU/mL, 95%CI: 7.7-11.4; p < 0.001). RBD-ACE2-inhibiting antibody titres and anti-RBD antibody concentrations strongly correlated at each timepoint (all r > 0.86, p < 0.001). Disease severity was associated with higher initial anti-RBD and RBD-ACE2-inhibiting antibody titres, but not with their kinetics. Neutralizing antibodies persisted at 6 months in almost all participants, indicating more durability than initially feared. Anti-RBD antibodies persisted better and even increased over time, possibly related to the preferential detection of progressively higher-affinity antibodies.
| S-EPMC7816882 | biostudies-literature
Project description:BackgroundMost SARS-CoV-2 infected patients develop IgG antibodies within 2-3 weeks after symptom onset. Antibody levels have been shown to gradually decrease in the first months after infection, but few data are available at six months or later.MethodsA retrospective multi-center study was performed using 652 samples of 236 PCR-confirmed SARS-CoV-2 infected patients from 2 Belgian University hospitals. Patients were included if at least two samples were available (range 2-7 samples); including at least one sample collected 30 days or later after first positive PCR (range 0-240 days). Of those 236 patients, 19.1 % were classified as mild/asymptomatic (mild) and 80.9 % as moderate to critical (severe). IgG anti-nucleocapsid antibodies (anti-N) were measured using the Abbott Architect immunoassay.Results22.2 % of mild and 2.6 % of severe COVID-19 cases never seroconverted (p < 0.001). Of the mild patients who seroconverted 0-59 days after PCR; 18.8 %, 40.0 % and 61.1 % were seronegative in the windows 60-119 days, 120-179 days and 180-240 days after PCR, respectively. In severe patients, these numbers were 1.9 %, 10.8 % and 29.4 % respectively (p < 0.05 each). Antibody levels were significantly higher in severe patients compared to mild patients in each 60 day window (p < 0.001 each).ConclusionsSARS-CoV-2 anti-N IgG antibody levels steadily decreased after 2 months up to 8 months post PCR. Of severe COVID-19 patients, 70.6 % remained positive up to eight months after infection. Antibody levels were significantly lower in mild SARS-CoV-2 infected patients and 61.1 % became seronegative within 6 months after the first positive PCR.
| S-EPMC7891078 | biostudies-literature
Project description:The immune response to SARS-CoV-2 is critical in controlling disease, but there is concern that waning immunity may predispose to reinfection. We analyzed the magnitude and phenotype of the SARS-CoV-2-specific T cell response in 100 donors at 6 months following infection. T cell responses were present by ELISPOT and/or intracellular cytokine staining analysis in all donors and characterized by predominant CD4+ T cell responses with strong interleukin (IL)-2 cytokine expression. Median T cell responses were 50% higher in donors who had experienced a symptomatic infection, indicating that the severity of primary infection establishes a 'set point' for cellular immunity. T cell responses to spike and nucleoprotein/membrane proteins were correlated with peak antibody levels. Furthermore, higher levels of nucleoprotein-specific T cells were associated with preservation of nucleoprotein-specific antibody level although no such correlation was observed in relation to spike-specific responses. In conclusion, our data are reassuring that functional SARS-CoV-2-specific T cell responses are retained at 6 months following infection.
| S-EPMC7610739 | biostudies-literature
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| S-EPMC8028697 | biostudies-literature
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| S-EPMC8486583 | biostudies-literature