RESUMO
BACKGROUND: University students commonly received COVID-19 vaccinations before returning to U.S. campuses in the Fall of 2021. Given likely immunologic variation among students based on differences in type of primary series and/or booster dose vaccine received, we conducted serologic investigations in September and December 2021 on a large university campus in Wisconsin to assess anti-SARS-CoV-2 antibody levels. METHODS: We collected blood samples, demographic information, and COVID-19 illness and vaccination history from a convenience sample of students. Sera were analyzed for both anti-spike (anti-S) and anti-nucleocapsid (anti-N) antibody levels using World Health Organization standardized binding antibody units per milliliter (BAU/mL). Levels were compared across categorical primary COVID-19 vaccine series received and binary COVID-19 mRNA booster status. The association between anti-S levels and time since most recent vaccination dose was estimated by mixed-effects linear regression. RESULTS: In total, 356 students participated, of whom 219 (61.5%) had received a primary vaccine series of Pfizer-BioNTech or Moderna mRNA vaccines and 85 (23.9%) had received vaccines from Sinovac or Sinopharm. Median anti-S levels were significantly higher for mRNA primary vaccine series recipients (2.90 and 2.86 log [BAU/mL], respectively), compared with those who received Sinopharm or Sinovac vaccines (1.63 and 1.95 log [BAU/mL], respectively). Sinopharm and Sinovac vaccine recipients were associated with a significantly faster anti-S decline over time, compared with mRNA vaccine recipients (P <.001). By December, 48/172 (27.9%) participants reported receiving an mRNA COVID-19 vaccine booster, which reduced the anti-S antibody discrepancies between primary series vaccine types. CONCLUSIONS: Our work supports the benefit of heterologous boosting against COVID-19. COVID-19 mRNA vaccine booster doses were associated with increases in anti-SARS-CoV-2 antibody levels; following an mRNA booster dose, students with both mRNA and non-mRNA primary series receipt were associated with comparable levels of anti-S IgG.
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Vacinas contra COVID-19 , COVID-19 , Humanos , COVID-19/prevenção & controle , Wisconsin/epidemiologia , Universidades , Anticorpos Antivirais , RNA MensageiroRESUMO
BACKGROUND: To improve understanding of the antibody response to SARS-CoV-2 infection, we examined seroprevalence, incidence of infection, and seroconversion among a cohort of young adults living on university campuses during the fall of 2020. METHODS: At the beginning (semester start) and end (semester end) of an 11-week period, serum collected from 107 students was tested using the qualitative Abbott Architect SARS-CoV-2 IgG and AdviseDx SARS-CoV-2 IgG II assays. Results were matched to interim weekly surveillance viral testing and symptom data. RESULTS: With the SARS-CoV-2 IgG assay, 15 (14.0%) students were seropositive at semester start; 29 (27.1%) students were seropositive at semester end; 10 (9.3%) were seropositive at both times. With the AdviseDx SARS-CoV-2 IgG II assay, 17 (16.3%) students were seropositive at semester start, 37 (35.6%) were seropositive at semester end, and 16 (15.3%) were seropositive at both times. Overall, 23 students (21.5%) had positive viral tests during the semester. Infection was identified by serial testing in a large majority of individuals who seroconverted using both assays. Those seropositive at semester end more frequently reported symptomatic infections (56.5%) than asymptomatic infections (30.4%). CONCLUSION: Differences between antibody targets were observed, with more declines in antibody index values below the threshold of positivity with the anti-nucleocapsid assay compared to the anti-spike assay. Serology testing, combined with serial viral testing, can detect seroconversions, and help understand the potential correlates of protection provided by antibodies to SARS-CoV-2.
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COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , COVID-19/diagnóstico , COVID-19/epidemiologia , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática , Humanos , Soroconversão , Estudos Soroepidemiológicos , Estudantes , UniversidadesRESUMO
We characterized serology following a nursing home outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) where residents were serially tested by reverse-transcription polymerase chain reaction (RT-PCR) and positive residents were cohorted. When tested 46-76 days later, 24 of 26 RT-PCR-positive residents were seropositive; none of the 124 RT-PCR-negative residents had confirmed seropositivity, supporting serial SARS-CoV-2 RT-PCR testing and cohorting in nursing homes.
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COVID-19 , SARS-CoV-2 , Surtos de Doenças , Humanos , Reação em Cadeia da Polimerase , Instituições de Cuidados Especializados de EnfermagemRESUMO
Rapid point-of-care tests (POCTs) for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies vary in performance. A critical need exists to perform head-to-head comparisons of these assays. The performances of 15 different lateral flow POCTs for the detection of SARS-CoV-2-specific antibodies were compared on a well-characterized set of 100 samples. Of these, 40 samples from known SARS-CoV-2-infected, convalescent individuals (collected an average of 45 days after symptom onset) were used to assess sensitivity. Sixty samples from the prepandemic era (negative control) that were known to represent infections with other respiratory viruses (rhinoviruses A, B, and C and/or coronavirus 229E, HKU1, and NL63 OC43) were used to assess specificity. The timing of seroconversion was assessed using five lateral flow assays (LFAs) and a panel of 272 longitudinal samples from 47 patients for whom the time since symptom onset was known. Among the assays that were evaluated, the sensitivity and specificity for any reactive band ranged from 55% to 97% and from 78% to 100%, respectively. Assessing the performance of the IgM and the IgG bands alone, sensitivity and specificity ranged from 0% to 88% and 80% to 100% for IgM and from 25% to 95% and 90% to 100% for IgG, respectively. Longitudinal testing revealed that the median times after symptom onset to a positive result were 7 days (interquartile range [IQR], 5.4 to 9.8) for IgM and 8.2 days (IQR, 6.3 to 11.3) for IgG. The testing performances differed widely among LFAs, with greatest amount of variation related to the sensitivity of the assays. The IgM band was the band most likely to misclassify prepandemic samples. The appearances of IgM and IgG bands occurred almost simultaneously.
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Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Testes Imediatos , SARS-CoV-2/isolamento & purificação , Anticorpos Antivirais/sangue , COVID-19/sangue , Reações Cruzadas , Humanos , Imunoensaio , Imunoglobulina G/sangue , Imunoglobulina M/sangue , SARS-CoV-2/imunologia , Sensibilidade e Especificidade , SoroconversãoRESUMO
The aim of this study was to assess the long-term dynamics and factors associated with the serological response against the severe acute respiratory syndrome coronavirus 2 after primary infection. A prospective longitudinal study was conducted with monthly serological follow-up during the first 4 months, and then at 6, 8, and 10 months after the disease onset of all recovered adult in- and outpatients with coronavirus disease 2019 (COVID-19) attending Udine Hospital (Italy) during the first wave (from March to May 2020). A total of 546 individuals were included (289 female, mean age 53.1 years), mostly with mild COVID-19 (370, 68.3%). Patients were followed for a median of 302 days (interquartile range, 186 to 311). The overall seroconversion rate within 2 months was 32% for IgM and 90% for IgG. Seroreversion was observed in 90% of patients for IgM at 4 months and in 47% for IgG at 10 months. Older age, number of symptoms at acute onset, and severity of acute COVID-19 were all independent predictors of long-term immunity both for IgM (ß, linear regression coefficient, 1.10, P = 0.001; ß 5.15 P = 0.014; ß 43.84 P = 0.021, respectively) and for IgG (ß 1.43 P < 0.001; ß 10.46 P < 0.001; ß 46.79 P < 0.001, respectively), whereas the initial IgG peak was associated only with IgG duration (ß 1.12, P < 0.001). IgM antibodies disappeared at 4 months, and IgG antibodies declined in about half of patients 10 months after acute COVID-19. These effects varied depending on the intensity of the initial antibody response, age, and burden of acute COVID-19.
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COVID-19 , SARS-CoV-2 , Adulto , Idoso , Anticorpos Antivirais , Formação de Anticorpos , Estado Terminal , Feminino , Humanos , Imunoglobulina M , Estudos Longitudinais , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Serological assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to support clinical diagnosis and epidemiological investigations. Recently, assays for large-scale detection of total antibodies (Ab), immunoglobulin G (IgG), and IgM against SARS-CoV-2 antigens have been developed, but there are limited data on the diagnostic accuracy of these assays. This study was a Danish national collaboration and evaluated 15 commercial and one in-house anti-SARS-CoV-2 assays in 16 laboratories. Sensitivity was evaluated using 150 samples from individuals with asymptomatic, mild, or moderate COVID-19, nonhospitalized or hospitalized, confirmed by nucleic acid amplification tests (NAAT); samples were collected 13 to 73 days either from symptom onset or from positive NAAT (patients without symptoms). Specificity and cross-reactivity were evaluated in samples collected prior to the SARS-CoV-2 epidemic from >586 blood donors and patients with autoimmune diseases, cytomegalovirus or Epstein-Barr virus infections, and acute viral infections. A specificity of ≥99% was achieved by all total-Ab and IgG assays except one, DiaSorin Liaison XL IgG (97.2%). Sensitivities in descending order were Wantai ELISA total Ab (96.7%), CUH-NOVO in-house ELISA total Ab (96.0%), Ortho Vitros total Ab (95.3%), YHLO iFlash IgG (94.0%), Ortho Vitros IgG (93.3%), Siemens Atellica total Ab (93.2%), Roche Elecsys total Ab (92.7%), Abbott Architect IgG (90.0%), Abbott Alinity IgG (median 88.0%), DiaSorin Liaison XL IgG (median 84.6%), Siemens Vista total Ab (81.0%), Euroimmun/ELISA IgG (78.0%), and Snibe Maglumi IgG (median 78.0%). However, confidence intervals overlapped for several assays. The IgM results were variable, with the Wantai IgM ELISA showing the highest sensitivity (82.7%) and specificity (99%). The rate of seropositivity increased with time from symptom onset and symptom severity.
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Anticorpos Antivirais/isolamento & purificação , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Imunoensaio , Infecções por Citomegalovirus , Ensaio de Imunoadsorção Enzimática , Infecções por Vírus Epstein-Barr , Herpesvirus Humano 4 , Humanos , Imunoglobulina G/isolamento & purificação , Imunoglobulina M/isolamento & purificação , Laboratórios , SARS-CoV-2 , Sensibilidade e EspecificidadeRESUMO
Plenty of serologic tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed so far, thus documenting the importance of evaluating the relevant features of the immune response to this viral agent. The performance of these assays is currently under investigation. Amongst them, LIAISON® SARS-CoV-2 S1/S2 IgG by DiaSorin and Elecsys Anti-SARS-CoV-2 cobas® by Roche are currently used by laboratory medicine hospital departments in Italy and many other countries. In the present study, we firstly compared two serologic tests on serum samples collected at two different time points from 46 laboratory-confirmed coronavirus disease-2019 (COVID-19) subjects. Secondly, 85 negative serum samples collected before the SARS-CoV-2 pandemic were analyzed. Thirdly, possible correlations between antibody levels and the resulting neutralizing activity against a clinical isolate of SARS-CoV-2 were evaluated. Results revealed that both tests are endowed with low sensitivity on the day of hospital admission, which increased to 97.8% and 100% for samples collected after 15 days for DiaSorin and Roche tests, respectively. The specificity evaluated for the two tests ranges from 96.5% to 100%, respectively. Importantly, a poor direct correlation between antibody titers and neutralizing activity levels was evidenced in the present study. These data further shed light on both potentials and possible limitations related to SARS-CoV-2 serology. In this context, great efforts are still necessary for investigating antibody kinetics to develop novel diagnostic algorithms. Moreover, further investigations on the role of neutralizing antibodies and their correlate of protection will be of paramount importance for the development of effective vaccines.
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Anticorpos Antivirais/sangue , Teste para COVID-19/métodos , COVID-19/imunologia , SARS-CoV-2/imunologia , Testes Sorológicos/métodos , Animais , Anticorpos Neutralizantes , COVID-19/sangue , COVID-19/epidemiologia , COVID-19/virologia , Chlorocebus aethiops , Humanos , Imunoglobulina G/sangue , Itália/epidemiologia , Pandemias , Sensibilidade e Especificidade , Células VeroRESUMO
The aim of the study was to assess reinfection rates in relation to long-term antibody dynamics against SARS-CoV-2 after the first wave. A prospective longitudinal study with monthly serological follow-up during the first 4 months, and then at 6, 8, and 10 months after the disease onset of all recovered adult in- and outpatients with COVID-19 attending Udine Hospital (Italy) from March to May 2020. During the follow-up, reinfections were collected. A total of 546 unselected individuals with COVID-19 acquired from March to May 2020 were included (292 female, mean age 53 years). After a median follow-up of 10 months (IQR 6.2-10.4), reinfection occurred in 6 (1.1%) patients, median age of 44.5 years (IQR 33â49). All had a previous history of mild COVID-19 (all were healthcare workers) and reinfection occurred a median of 9 months (IQR 8.2â10.2) after the onset of the first episode. Patients with reinfection were either seronegative (2/56, n = 3.6%), seroreverted (2/137, 1.5%), or seropositive (2/353, 0.6%) (p = 0.085). All reinfections were mild (n = 5) or asymptomatic (n = 1). After reinfection, none of patients developed IgM response and only two had a transitory boosted IgG immunization response. In an unselected population after the first wave of COVID-19, after a prolonged observation period (mean 10 months), reinfection was very uncommon; occurred in patients with a previous history of mild infection, mostly with weak or absent serological response; and manifested with mild or asymptomatic clinical presentation.
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Anticorpos Antivirais/sangue , COVID-19/sangue , Reinfecção/virologia , Adulto , COVID-19/virologia , Feminino , Seguimentos , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reinfecção/sangue , SARS-CoV-2/genética , SARS-CoV-2/imunologiaAssuntos
COVID-19 , SARS-CoV-2 , Vacina BNT162 , Vacinas contra COVID-19 , Pessoal de Saúde , Humanos , Imunoensaio , Imunoglobulina G , RNA Mensageiro , VacinaçãoAssuntos
COVID-19 , Procedimentos Cirúrgicos Cardíacos , Convalescença , Humanos , Inflamação , SARS-CoV-2RESUMO
OBJECTIVES: To describe the dynamics and factors related to natural and hybrid humoral response against the SARS-CoV-2 and risk of reinfection among first-wave patients. METHODS: A prospective longitudinal study with periodic serological follow-up after acute onset of all recovered patients with SARS-CoV-2 infection cared in Udine Hospital (March-May 2020). Nucleocapsid (N) protein and spike receptor-binding domain (S-RBD) antibody tests were used to distinguish natural and vaccine-induced response. RESULTS: Overall, 153 patients (66 men, mean age 56 years) were followed for a median of 27.3 (interquartile range 26.9-27.8) months. Seroreversion was 98.5% (95% CI: 96.8-99.4) for SARS-CoV-2-N IgM at 1 year and 57.4% (95% CI: 51.5-63.5) for SARS-CoV-2-N IgG at 2 years. Initial serological response (hazard ratio [HR]: 0.99, 95% CI: 0.99-0.99, p 0.002 for IgM and HR: 0.97, 95% CI: 0.97-0.98, p < 0.001 for IgG) and severity of acute infection (HR: 0.62, 95% CI: 0.39-0.96, p 0.033 for IgM and HR: 0.60, 95% CI: 0.37-0.99, p < 0.001 for IgG) were independently associated with persistent SARS-CoV-2-N IgM/IgG response. Older age and smoker status were associated with long-term SARS-CoV-2-N IgM and SARS-CoV-2-N IgG, respectively (HR: 0.75, 95% CI: 0.57-0.98, p 0.038; HR: 1.77, 95% CI: 1.19-2.61, p 0.004 respectively). All patients maintained SARS-CoV-2-S-RBD IgG response at 24-month follow-up. Reinfections occurred in 25 of 153 (16.3%) patients, mostly during the omicron circulation. Reinfection rates did not differ significantly between SARS-CoV-2-N IgG seronegative and seropositive patients (14/89, 15.7% vs. 10/62, 16.1%, p 0.947). Unvaccinated patients had higher risk of reinfection (4/7, 57.1% vs. vaccinated 21/146, 14.4%, p 0.014). DISCUSSION: First-wave patients had durable natural humoral immunity in 40% and anti-S-RBD response in 100% up to 2 years after infection. Natural humoral response alone was not protective against reinfections with omicron SARS-CoV-2 variants, whereas vaccination was effective to reduce the risk of a new infection.
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COVID-19 , Masculino , Humanos , Pré-Escolar , COVID-19/epidemiologia , Formação de Anticorpos , Reinfecção/epidemiologia , SARS-CoV-2 , Estudos Longitudinais , Estudos Prospectivos , Anticorpos Antivirais , Imunoglobulina G , Imunoglobulina MRESUMO
OBJECTIVE: Multisystem inflammatory syndrome in children (MIS-C) is a rare yet serious pathological consequence of SARS-CoV-2 infection which is reported 4-12 weeks after the onset of COVID-19 in children and adolescents. The most common hyper-inflammatory conditions mimicking the clinical presentation of MIS-C include Kawasaki disease and toxic shock syndrome. The surveillance criteria of MIS-C were recently revised by US Center for Disease Control and Prevention to improve diagnostic precision. Although previous studies have shown that SARS-CoV-2 antibody titers correlate with COVID-19 severity, their relation to MIS-C severity remains poorly understood and the aim of the study was to investigate this. METHODS: As all the MIS-C patients get a SARS-CoV-2 antibody test performed on the first day of hospitalization, here we attempted to stratify risk for adverse outcomes due to MIS-C based on the SARS-CoV-2 antibody titers. RESULTS: Our studies demonstrated that SARS-CoV-2 antibody titers, specifically Total (IgG/IgM/partial IgA), Nucleocapsid IgG, and Spike IgM, do not correlate with MIS-C severity assessed based on the ICU admission, inotropic support, and mechanical respiratory support requirements. CONCLUSION: Therefore, it might not be appropriate to predict the clinical course of patients presenting with MISC based on quantitative serology testing.
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COVID-19 , Adolescente , Criança , Humanos , SARS-CoV-2 , Anticorpos Antivirais , Imunoglobulina G , Imunoglobulina MRESUMO
The aim of this study is to report the seroprevalence of SARS-CoV-2 antibodies in healthcare workers with various risk of occupational exposure in Kalmar County, Sweden, during the first year of the coronavirus disease 2019 (COVID-19) pandemic. We performed SARS-CoV-2 antibody measurements at four time points, from May 2020 to May 2021, in 401 healthcare workers (HCW) at seven hospital wards and two residential care facilities, with different risk of SARS-CoV-2 exposure. Overall, the prevalence of SARS-CoV-2 antibodies in HCW in Kalmar County was high compared to similar studies from other countries and increased from May 2020 to May 2021. Initially, 14% of the participants were SARS-CoV-2 seropositive. This number increased to 18% in September and 21% in December 2020. In May 2021, the prevalence of antibodies to nucleocapsid antigen had increased to 28%, while antibodies to spike protein had increased to 95% due to vaccination. A large variation in seroprevalence between different wards was detected and HCW in a COVID-19 designated ward had significantly higher seroprevalence than HCW working in wards without COVID-19 patients, with a risk ratio of 7.28, (95% CI 2.38-22.33) in May 2020. Our findings suggest a relationship between occupational COVID-19 exposure and seropositivity which implies that efficient hygiene routines for health- and social care workers are essential to avoid that COVID-19 care will constitute an occupational hazard.
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COVID-19 , Humanos , COVID-19/epidemiologia , SARS-CoV-2 , Pandemias , Suécia/epidemiologia , Estudos Prospectivos , Estudos Soroepidemiológicos , Anticorpos Antivirais , Pessoal de Saúde , HospitaisRESUMO
OBJECTIVES: To investigate serological correlates of protection against SARS-CoV-2 B.1.617.2 (Delta) infection after two vaccinations. METHODS: We performed a case-control study, where cases were Delta infections after the second vaccine dose and controls were vaccinated, never infected participants, matched by age, gender and region. Sera were tested for anti-SARS-CoV-2 Spike antibody levels (anti-S) and neutralising antibody titres (nAbT), using live virus microneutralisation against Ancestral, Delta and Omicron (BA.1, B.1.1.529). We modelled the decay of anti-S and nAbT for both groups, inferring levels at matched calendar times since the second vaccination. We assessed differences in inferred antibody titres between groups and used conditional logistic regression to explore the relationship between titres and odds of infection. RESULTS: In total, 130 sequence-confirmed Delta cases and 318 controls were included. Anti-S and Ancestral nAbT decayed similarly between groups, but faster in cases for Delta nAbT (p = 0.02) and Omicron nAbT (p = 0.002). At seven days before infection, controls had higher anti-S levels (p < 0.0001) and nAbT (p < 0.0001; all variants) at matched calendar time. A two-fold increase in anti-S levels was associated with a 29% ([95% CI 14-42%]; p = 0.001) reduction in odds of Delta infection. Delta nAbT>40 were associated with reduced odds of Delta infection (89%, [69-96%]; p < 0.0001), with additional benefits for titres >100 (p = 0.009) and >400 (p = 0.007). CONCLUSIONS: We have identified correlates of protection against SARS-CoV-2 Delta, with potential implications for vaccine deployment, development, and public health response.
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Hepatite D , Vacinas , Humanos , Estudos de Casos e Controles , Anticorpos Neutralizantes , Vacinação , Anticorpos Antivirais , Reino Unido/epidemiologiaRESUMO
To facilitate interpretation of clinical SARS-CoV-2 anti-spike IgG analyses post-vaccination, 82 healthcare workers were followed through three vaccination-regimens: two regimens were comprised of two doses of BNT162b2 three or six weeks apart, followed by a dose of mRNA-vaccine, and in the other regimen, the first dose was replaced by ChAdOx1 nCov-19. After each dose, anti-spike IgG was compared between regimens. As many participants became infected, anti-spike IgG persistence was compared between infected and uninfected participants. Thirteen to twenty-one days after the first dose, seroconversion, and the median anti-spike IgG level in the ChAdOx1 group was significantly lower than in the BNT162b2 groups (23 versus 68 and 73 AU/mL). The second dose caused a significant increase in anti-spike IgG, but the median level was lower in the BNT162b2-short-interval group (280 AU/mL), compared to the BNT162b2-long-interval (1075 AU/mL) and ChAdOx1 (1160 AU/mL) group. After the third dose, all groups showed increases to similar anti-spike IgG levels (2075-2390 AU/mL). Over the next half year, anti-spike IgG levels declined significantly in all groups, but appeared to persist longer after post-vaccination infection. This is the first three-dose study with one dose of ChAdOx1. Despite initial differences, all vaccine regimens gave similarly high antibody levels and persistence after the third dose.
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Vacina BNT162 , COVID-19 , Humanos , COVID-19/prevenção & controle , Vacinas contra COVID-19 , ChAdOx1 nCoV-19 , Estudos Longitudinais , SARS-CoV-2 , Vacinação , Anticorpos Antivirais , Pessoal de Saúde , Imunoglobulina GRESUMO
In 2019, an emerging coronavirus, SARS-COV-2, was first identified. In the months since, SARS-CoV-2 has become a global pandemic of unimaginable scale. In 2021, SARS-CoV-2 continues to be a huge public health burden and a dominating issue in health care. In addition, SARS-CoV-2 has placed a spotlight on laboratory medicine and its key role in infectious disease management. The SARS-CoV-2 antibody testing landscape is vast and consists of dozens of antibody tests that have received EUA. The laboratory is faced with choosing the right test, staying current with the rapidly evolving recommendations, and updating test information for clients and clinicians. This review addresses what we know about the humoral response in SARS-CoV-2 infection and how this knowledge translates into appropriate serology test choice, utility, and interpretation.
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COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , Humanos , Laboratórios , PandemiasRESUMO
OBJECTIVES: To investigate serological differences between SARS-CoV-2 reinfection cases and contemporary controls, to identify antibody correlates of protection against reinfection. METHODS: We performed a case-control study, comparing reinfection cases with singly infected individuals pre-vaccination, matched by gender, age, region and timing of first infection. Serum samples were tested for anti-SARS-CoV-2 spike (anti-S), anti-SARS-CoV-2 nucleocapsid (anti-N), live virus microneutralisation (LV-N) and pseudovirus microneutralisation (PV-N). Results were analysed using fixed effect linear regression and fitted into conditional logistic regression models. RESULTS: We identified 23 cases and 92 controls. First infections occurred before November 2020; reinfections occurred before February 2021, pre-vaccination. Anti-S levels, LV-N and PV-N titres were significantly lower among cases; no difference was found for anti-N levels. Increasing anti-S levels were associated with reduced risk of reinfection (OR 0·63, CI 0·47-0·85), but no association for anti-N levels (OR 0·88, CI 0·73-1·05). Titres >40 were correlated with protection against reinfection for LV-N Wuhan (OR 0·02, CI 0·001-0·31) and LV-N Alpha (OR 0·07, CI 0·009-0·62). For PV-N, titres >100 were associated with protection against Wuhan (OR 0·14, CI 0·03-0·64) and Alpha (0·06, CI 0·008-0·40). CONCLUSIONS: Before vaccination, protection against SARS-CoV-2 reinfection was directly correlated with anti-S levels, PV-N and LV-N titres, but not with anti-N levels. Detectable LV-N titres were sufficient for protection, whilst PV-N titres >100 were required for a protective effect. TRIAL REGISTRATION NUMBER: ISRCTN11041050.
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COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , COVID-19/prevenção & controle , Estudos de Casos e Controles , Humanos , Reinfecção/prevenção & controle , VacinaçãoRESUMO
Well-regulated clinical trials have shown FDA-approved COVID-19 vaccines to be immunogenic and highly efficacious. We evaluated seroconversion rates in adults reporting ≥ 1 dose of an mRNA COVID-19 vaccine in a cohort study of nearly 8000 adults residing in North Carolina to validate immunogenicity using a novel approach: at-home, participant administered point-of-care testing. Overall, 91.4% had documented seroconversion within 75 days of first vaccination (median: 31 days). Participants who were older and male participants were less likely to seroconvert (adults aged 41-65: adjusted hazard ratio [aHR] 0.69 [95% confidence interval (CI): 0.64, 0.73], adults aged 66-95: aHR 0.55 [95% CI: 0.50, 0.60], compared to those 18-40; males: aHR 0.92 [95% CI: 0.87, 0.98], compared to females). Participants with evidence of prior infection were more likely to seroconvert than those without (aHR 1.50 [95% CI: 1.19, 1.88]) and those receiving BNT162b2 were less likely to seroconvert compared to those receiving mRNA-1273 (aHR 0.84 [95% CI: 0.79, 0.90]). Reporting at least one new symptom after first vaccination did not affect time to seroconversion, but participants reporting at least one new symptom after second vaccination were more likely to seroconvert (aHR 1.11 [95% CI: 1.05, 1.17]). This data demonstrates the high community-level immunogenicity of COVID-19 vaccines, albeit with notable differences in older adults, and feasibility of using at-home, participant administered point-of-care testing for community cohort monitoring. Trial registration: ClinicalTrials.gov NCT04342884.
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COVID-19 , Vacinas , Idoso , Anticorpos Antivirais , Vacina BNT162 , COVID-19/prevenção & controle , Vacinas contra COVID-19/efeitos adversos , Estudos de Coortes , Feminino , Humanos , Imunogenicidade da Vacina , Masculino , North Carolina/epidemiologia , RNA Mensageiro , SoroconversãoRESUMO
Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has been identified as the causative agent of COVID-19. Accurate detection of SARS-CoV-2 infection is not only important for management of infected individuals but also to break the chain of transmission. Although the polymerase chain reaction (PCR) is the gold standard for diagnosis of acute SARS-CoV-2 infection, there are a number of limitations of these assays, which include the inability to detect past infection and decline in sensitivity 14 days post-symptom onset. There are several serology tests developed for the detection of SARS-CoV-2 antibodies including high-throughput serology platforms and lateral flow immunoassays. These tests should be evaluated for their performance to meet local regulations acceptance criteria. To optimize the diagnostic algorithm for SARS-CoV-2, this protocol describes the evaluation of serological antibody testing using various automated serology platforms and lateral flow immunoassays. This protocol was evaluated in both serum and plasma samples. The sample preparation, procedure, and data analysis are described. The protocol can be adapted for any serological testing.