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1.
Klin Lab Diagn ; 65(11): 688-692, 2020 Dec 04.
Article in English | MEDLINE | ID: covidwho-1780383

ABSTRACT

The study presents the results of the creation and evaluation of the diagnostic characteristics of the rapid immunochromatographic test for the qualitative detection and differentiation of IgM/IgG antibodies to SARS-CoV-2 in human serum, plasma, and whole blood "ИХА-COVID-19-IgM / IgG". Have been tested some samples without antibodies to SARS-CoV-2 and a samples with two and one type of specific antibodies. The coincidence of the results of immunochromatographic analysis with the results of the immunochemiluminescent method was 87.2%. Test kit can be use as the rapid diagnostic test in the context of the COVID-19 pandemic and to assess the immune status of convalescents.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing , COVID-19/diagnosis , Immunoassay , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Humans
2.
Immunology ; 164(1): 135-147, 2021 09.
Article in English | MEDLINE | ID: covidwho-1295026

ABSTRACT

Detecting antibody responses during and after SARS-CoV-2 infection is essential in determining the seroepidemiology of the virus and the potential role of antibody in disease. Scalable, sensitive and specific serological assays are essential to this process. The detection of antibody in hospitalized patients with severe disease has proven relatively straightforward; detecting responses in subjects with mild disease and asymptomatic infections has proven less reliable. We hypothesized that the suboptimal sensitivity of antibody assays and the compartmentalization of the antibody response may contribute to this effect. We systematically developed an ELISA, optimizing different antigens and amplification steps, in serum and saliva from non-hospitalized SARS-CoV-2-infected subjects. Using trimeric spike glycoprotein, rather than nucleocapsid, enabled detection of responses in individuals with low antibody responses. IgG1 and IgG3 predominate to both antigens, but more anti-spike IgG1 than IgG3 was detectable. All antigens were effective for detecting responses in hospitalized patients. Anti-spike IgG, IgA and IgM antibody responses were readily detectable in saliva from a minority of RT-PCR confirmed, non-hospitalized symptomatic individuals, and these were mostly subjects who had the highest levels of anti-spike serum antibodies. Therefore, detecting antibody responses in both saliva and serum can contribute to determining virus exposure and understanding immune responses after SARS-CoV-2 infection.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antigens, Viral/immunology , COVID-19/blood , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Humans , Saliva
3.
Neurol Sci ; 42(9): 3527-3530, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1274855

ABSTRACT

Neurological manifestations of SARS-CoV-2 are increasingly being recognised and can arise as a result of direct viral invasion, para-infectious or postinfectious immune mechanisms. We report a delayed presentation of COVID-19 postinfectious immune-mediated encephalitis and status epilepticus occurring in a 47-year-old woman 4 weeks after SARS-CoV-2 pulmonary disease. SARS-CoV-2-specific IgG and IgM antibodies were detected in her cerebrospinal fluid with features of encephalitis evident in both magnetic resonance imaging of the brain and electroencephalogram. She made a complete recovery following treatment with high-dose intravenous corticosteroids and intravenous immunoglobulins. Diagnosis of COVID-19 postinfectious encephalitis may prove challenging in patients presenting many weeks following the initial infection. A high index of clinical suspicion and testing intrathecal SARS-CoV-2-specific antibodies are key to its diagnosis. Early immunotherapy is likely to result in a good outcome.


Subject(s)
COVID-19 , Encephalitis , Electroencephalography , Encephalitis/complications , Female , Humans , Magnetic Resonance Imaging , Middle Aged , SARS-CoV-2
4.
Anal Chem ; 93(25): 8754-8763, 2021 06 29.
Article in English | MEDLINE | ID: covidwho-1267985

ABSTRACT

To tackle the COVID-19 outbreak, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is an unmet need for highly accurate diagnostic tests at all stages of infection with rapid results and high specificity. Here, we present a label-free nanoplasmonic biosensor-based, multiplex screening test for COVID-19 that can quantitatively detect 10 different biomarkers (6 viral nucleic acid genes, 2 spike protein subunits, and 2 antibodies) with a limit of detection in the aM range, all within one biosensor platform. Our newly developed nanoplasmonic biosensors demonstrate high specificity, which is of the upmost importance to avoid false responses. As a proof of concept, we show that our detection approach has the potential to quantify both IgG and IgM antibodies directly from COVID-19-positive patient plasma samples in a single instrument run, demonstrating the high-throughput capability of our detection approach. Most importantly, our assay provides receiving operating characteristics, areas under the curve of 0.997 and 0.999 for IgG and IgM, respectively. The calculated p-value determined through the Mann-Whitney nonparametric test is <0.0001 for both antibodies when the test of COVID-19-positive patients (n = 80) is compared with that of healthy individuals (n = 72). Additionally, the screening test provides a calculated sensitivity (true positive rate) of 100% (80/80), a specificity (true negative rate) >96% (77/80), a positive predictive value of 98% at 5% prevalence, and a negative predictive value of 100% at 5% prevalence. We believe that our very sensitive, multiplex, high-throughput testing approach has potential applications in COVID-19 diagnostics, particularly in determining virus progression and infection severity for clinicians for an appropriate treatment, and will also prove to be a very effective diagnostic test when applied to diseases beyond the COVID-19 pandemic.


Subject(s)
Biosensing Techniques , COVID-19 , Antibodies, Viral , Humans , Immunoglobulin G , Immunoglobulin M , Pandemics , RNA , SARS-CoV-2 , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus
5.
Cell Rep Med ; 2(6): 100321, 2021 06 15.
Article in English | MEDLINE | ID: covidwho-1253745

ABSTRACT

The pathogenesis of severe coronavirus disease 2019 (COVID-19) remains poorly understood. While several studies suggest that immune dysregulation plays a central role, the key mediators of this process are yet to be defined. Here, we demonstrate that plasma from a high proportion (93%) of critically ill COVID-19 patients, but not healthy controls, contains broadly auto-reactive immunoglobulin M (IgM) and less frequently auto-reactive IgG or IgA. Importantly, these auto-IgMs preferentially recognize primary human lung cells in vitro, including pulmonary endothelial and epithelial cells. By using a combination of flow cytometry, analytical proteome microarray technology, and lactose dehydrogenase (LDH)-release cytotoxicity assays, we identify high-affinity, complement-fixing, auto-reactive IgM directed against 260 candidate autoantigens, including numerous molecules preferentially expressed on the cellular membranes of pulmonary, vascular, gastrointestinal, and renal tissues. These findings suggest that broad IgM-mediated autoimmune reactivity may be involved in the pathogenesis of severe COVID-19, thereby identifying a potential target for therapeutic interventions.


Subject(s)
Autoantibodies/immunology , COVID-19/pathology , Immunoglobulin M/immunology , Autoantibodies/blood , COVID-19/immunology , COVID-19/virology , Cell Line , Complement C4/metabolism , Critical Illness , Humans , Immunoglobulin M/blood , Intensive Care Units , Lung/metabolism , Protein Array Analysis , Proteome/analysis , SARS-CoV-2/isolation & purification
6.
J Taibah Univ Med Sci ; 16(4): 619-623, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1253296

ABSTRACT

OBJECTIVE: This study investigates the association of preventive measures with coronavirus disease (COVID-19) seropositivity. METHODS: This cross-sectional study was conducted at the Combined Military Hospital Kharian Medical College, Pakistan, in September 2020. A total of 442 participants from three different strata (faculty, students, and administration/technical staff) were enrolled using a convenient sampling technique. A rapid antibody testing method was used to detect antibodies. The Ichroma™ COVID-19 Ab test is an in vitro diagnostic device that helps in the rapid identification of COVID-19 by measuring the levels of IgG and IgM antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the blood. An automated fluorescent immunoassay system (AFIAS-6), with a clinical sensitivity of 95.8% and specificity of 96.7%, was used for qualitative analysis. A self-administered questionnaire was used to collect data, and data analysis was performed using SPSS version 25. RESULTS: In total, 442 participants were included in the study: 40 (9%) faculty members, 299 (67%) students, and 103 (23.3%) administrative/technical staff. As many as 14.9% of the participants were symptomatic; 32.4% always used masks, and 14% never wore masks. Furthermore, 69.7% of participants frequently washed their hands for 20 s, and 75.6% were aware of social distancing. A total of 16.96% of participants tested positive for IgG antibodies. Moreover, most of the administration/technical staff who tested positive for IgG were asymptomatic (68.42%). A significant association (p < 0.001) was found between following the safety guidelines (wearing masks, handwashing, and social distancing) and the occurrence of COVID-19. CONCLUSION: This study showed a higher seroprevalence rate than other studies as it was conducted toward the end of the first wave of the COVID-19 pandemic. However, we are still far from achieving herd immunity. Furthermore, strict compliance with preventive measures is the only way to ensure safety until an effective vaccine is developed.

7.
J Med Virol ; 93(9): 5409-5415, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1209995

ABSTRACT

Timing of detection of immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and their use to support the diagnosis are of increasing interest. We used the Gold Standard Diagnostics ELISA to evaluate the kinetics of SARS-CoV-2 IgG, IgA, and IgM antibodies in sera of 82 hospitalized patients with polymerase chain reaction (PCR)-confirmed coronavirus disease 2019 (COVID-19). Serum samples were collected 1-59 days post-onset of symptoms (PoS) and we examined the association of age, sex, disease severity, and symptoms' duration with antibody levels. We also tested sera of 100 ambulatory hospital employees with PCR-confirmed COVID-19 and samples collected during convalescence, 35-57 days PoS. All but four of the admitted patients (95.1%) developed antibodies to SARS-CoV-2. Antibodies were detected within 7 days PoS; IgA in 60.0%, IgM in 53.3%, and IgG in 46.7% of samples. IgG positivity increased to 100% on Day 21. We did not observe significant differences in the rate of antibody development in regard to age and sex. IgA levels were highest in patients with a severe and critical illness. In multiple regression analyses, only IgA levels were statistically significantly correlated with critical disease (p = .05) regardless of age, sex, and duration of symptoms. Among 100 ambulatory hospital employees who had antibody testing after 4 weeks PoS only 10% had positive IgA antibodies. The most frequently isolated isotype in sera of employees after 30 days PoS was IgG (88%). IgA was the predominant immunoglobulin in early disease and correlated independently with a critical illness. IgG antibodies remained detectable in almost 90% of samples collected up to two months after infection.


Subject(s)
Antibodies, Viral/blood , COVID-19/immunology , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , COVID-19/blood , COVID-19/diagnosis , COVID-19/mortality , COVID-19 Serological Testing , Convalescence , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Sensitivity and Specificity , Severity of Illness Index , Survival Analysis
8.
J Med Virol ; 93(3): 1361-1369, 2021 03.
Article in English | MEDLINE | ID: covidwho-1196509

ABSTRACT

Current evidence suggests that coronavirus disease 2019 (COVID-19), caused by severe respiratory syndrome coronavirus 2 (SARS-CoV-2), is predominantly transmitted from human-to-human. However, evidence on vertical transmission and natural passive immunity among the newborns exposed to COVID-19 is scanty and varies. This poses a challenge on preventive interventions for the newborns. We conducted a systematic review to first, determine the likelihood of vertical transmission among COVID-19 exposed infants and second, determine whether antibodies against SARS-CoV-2 were generated among COVID-19 vertically exposed but negative infants. This review registered in PROSPERO searched evidence from PubMed/MEDLINE and Google Scholar, among others. About 517 studies were pooled, where 33 articles (5.8%) met the inclusion criteria such as infection prevention and control measures at birth. A total of 205 infants born to COVID-19 positive mothers were studied. Overall, 6.3% (13/205; 95% CI: 3.0%-9.7%) of the infants tested positive for COVID-19 virus at birth. Of 33 eligible studies, six studies (18.8%) reported about immunoglobulin G/M (IgG/IgM) against SARS-CoV-2. IgG/IgM were detected in 90% infants (10/11; 95% CI: 73.9%-107.9%) who tested negative for COVID-19 virus. The median antibody levels detected were 75.49 AU/ml (range, 7.25-140.32 AU/ml) and 3.79 AU/ml (range, 0.16-45.83 AU/ml), p = .0041 for IgG and IgM, respectively. In conclusion, the current evidence revealed a low possibility of vertical transmission of COVID-19 and antibodies against SARS-CoV-2 were detected among vertically exposed but negative infants. Further studies on transplacental transmission and the magnitude of natural passive immunity in infants born to mothers with COVID-19 are warranted.


Subject(s)
Antibodies, Viral/blood , COVID-19/transmission , Infectious Disease Transmission, Vertical , Pregnancy Complications, Infectious , SARS-CoV-2/immunology , COVID-19/immunology , COVID-19 Serological Testing , Female , Humans , Immunity, Maternally-Acquired , Immunoglobulin G/blood , Immunoglobulin M/blood , Infant, Newborn , Pregnancy , Seroepidemiologic Studies
9.
J Pediatr Endocrinol Metab ; 34(7): 925-936, 2021 Jul 27.
Article in English | MEDLINE | ID: covidwho-1197410

ABSTRACT

OBJECTIVES: COVID-19 pandemic significantly impacted the diagnosis of type 1 diabetes and its acute complications. Thus, the study aimed to evaluate the characteristics of pediatric patients with type 1 diabetes hospitalized during the first wave of the pandemic and the prevalence of new onset diabetes among patients with evidence of COVID-19 infection. METHODS: A single-center surveillance study included all patients with diabetes admitted to Children's Hospital, Ain Shams University, in Egypt between May to August 2020. Data were collected to evaluate patients' clinical and laboratory characteristics as well as their outcomes. RESULTS: Thirty-six patients were admitted during the study period. The mean age was 8.4 ± 3.8 years. Patients presented late to the emergency department with a mean delay of 3.05 ± 1.19 days from onset of symptoms. 34/36 patients presented in diabetic ketoacidosis (DKA), 50% presenting in severe DKA. Almost 81% of the patients were newly diagnosed. During the study period, SARS-CoV-2 PCR was found positive in four patients, COVID Ig M antibodies were positive in another two patients; all were symptomatic requiring ICU admission. Four patients showed a picture suggestive of the multi-inflammatory syndrome (MIS-C); cardiac affection was a constant feature. CONCLUSIONS: The pandemic affected both the prevalence and severity of DKA among pediatric patients. The increased prevalence of severe DKA could be partly related to delayed hospital admission or the effect of COVID-19 in triggering DKA. Efforts should be done to continuously raise awareness about diabetes in children as well as the importance of seeking timely medical guidance.


Subject(s)
COVID-19/epidemiology , Diabetes Mellitus, Type 1/complications , Diabetic Ketoacidosis/epidemiology , SARS-CoV-2 , Adolescent , Child , Child, Hospitalized , Child, Preschool , Egypt/epidemiology , Female , Humans , Logistic Models , Male , Severity of Illness Index
10.
Front Pediatr ; 8: 601327, 2020.
Article in English | MEDLINE | ID: covidwho-1186848

ABSTRACT

Background: The occurrence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the associated coronavirus disease 2019 (COVID-19) have profoundly affected adult kidney disease patients. In contrast, pediatric solid organ transplant recipients, including pediatric kidney transplant (KT) recipients, do not seem to be at particularly higher risk for SARS-CoV-2 infection or for severe COVID-19 disease. This patient population might be protected by certain mechanisms, such as the immunosuppressive medications with their anti-inflammatory properties or simply being well-versed in self-protection techniques. Assessing SARS-CoV-2 antibody serologies could potentially help understand why this patient population is apparently spared from severe SARS-CoV-2 clinical courses. Objective: To examine SARS-CoV-2 serologic status in a cohort of pediatric KT recipients. Methods: SARS-CoV-2 anti-spike IgG and IgM antibodies were measured by three different methods in pediatric KT recipients coming for routine clinic visits immediately post-confinement in May-June of 2020. The patients were considered seroconverted if SARS-CoV-2 antibodies were positive by 2/3 methods and weak positive/indeterminate if positive by 1/3. Results: Thirty-one patients were evaluated (about 1/3 of our institution's pediatric KT population). One patient seroconverted, while three were considered weak positive/indeterminate. None were symptomatic and none had nasopharyngeal PCR confirmed SARS-CoV-2 disease. Conclusions: Seroconversion to SARS-CoV-2 was rare in this population and likely reflects the social distancing practiced by these patients. The results will serve as a foundation for a future longitudinal study to evaluate the long-term emergence and persistence of antibodies in this population and may inform studies of response to a future vaccine.

11.
J King Saud Univ Sci ; 33(4): 101439, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1185114

ABSTRACT

By the end of year 2019, the new virus SARS-CoV-2 appeared, causing the Coronavirus Disease 2019 (COVID-19), and spread very fast globally. A continuing need for diagnostic tools is a must to contain its spread. Till now, the gold standard method, the reverse transcription polymerase chain reaction (RT-PCR), is the precise procedure to detect the virus. However, SARS-CoV-2 may escape RT-PCR detection for several reasons. The development of well-designed, specific and sensitive serological test like enzyme immunoassay (EIA) is needed. This EIA can stand alone or work side by side with RT-PCR. In this study, we developed several EIAs including plates that are coated with either specially designed SARS-CoV-2 nucleocapsid or surface recombinant proteins. Each protein type can separately detect anti-SARS-CoV-2 IgM or IgG antibodies. For each EIAs, the cut-off value, specificity and sensitivity were determined utilizing RT-PCR confirmed Covid-19 and pre-pandemic healthy and other viruses-infected sera. Also, the receiver operator characteristic (ROC) analysis was performed to define the specificities and sensitivities of the optimized assay. The in-house EIAs were validated by comparing against commercial EIA kits. All in-house EIAs showed high specificity (98-99%) and sensitivity (97.8-98.9%) for the detection of IgG/IgM against RBD and N proteins of SARS-CoV-2. From these results, the developed Anti-RBD and anti-N IgG and IgM antibodies EIAs can be used as a specific and sensitive tool to detect SARS-CoV-2 infection, calculate the burden of disease and case fatality rates.

12.
Tzu Chi Med J ; 33(2): 146-153, 2021.
Article in English | MEDLINE | ID: covidwho-1187094

ABSTRACT

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic caused by the SARS-CoV2 virus continues to pose a serious threat to public health worldwide. The development of rapid diagnostic kits can assist the Tzu Chi Foundation in supporting global volunteers working to provide relief during the current pandemic. MATERIALS AND METHODS: In this study, nucleotide sequences derived from publicly available viral genome data for several domains of the SARS-CoV2 spike and nucleocapsid (N) proteins were chemically synthesized, with codon optimization for Escherichia coli protein expression. No actual viral particles were involved in these experiments. The synthesized sequences were cloned into an E. coli expression system based on pQE80L, and expressed viral proteins were subsequently purified using Ni-affinity chromatography. Western blotting was conducted using human antiviral sera to assess the response of codon-modified viral proteins to COVID-19 patient sera. RESULTS: N protein was expressed in amounts large enough to support large-scale production. The N-terminal domain, receptor-binding domain (RBD), Region 3, and the S2 domain were expressed in small but sufficient amounts for experiments. Immunoblotting results showed that anti-N IgG and anti-N IgM antibodies were detected in most patient sera, but only 60% of samples reacted with the recombinant RBD and S2 domain expressed by E. coli. CONCLUSION: The results indicated that codon-optimized SARS-CoV2 viral proteins can be expressed in E. coli and purified for rapid antibody detection kit preparation, with the codon-optimized N protein, RBD, and S2 protein demonstrating the most potential.

13.
PLoS One ; 16(4): e0249449, 2021.
Article in English | MEDLINE | ID: covidwho-1171683

ABSTRACT

OBJECTIVES: To determine the seroprevalence of anti-SARS-CoV-2 IgG and IgM antibodies in symptomatic Japanese COVID-19 patients. METHODS: Serum samples (n = 114) from 34 COVID-19 patients with mild to critical clinical manifestations were examined. The presence and titers of IgG antibody for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were determined by a chemiluminescent microparticle immunoassay (CMIA) using Alinity i SARS-CoV-2 IgG and by an immunochromatographic (IC) IgM/IgG antibody assay using the Anti-SARS-CoV-2 Rapid Test. RESULTS: IgG was detected by the CMIA in 40%, 88%, and 100% of samples collected within 1 week, 1-2 weeks, and 2 weeks after symptom onset in severe and critical cases, and 0%, 38%, and 100% in mild/moderate cases, respectively. In severe and critical cases, the positive IgG detection rate with the IC assay was 60% within one week and 63% between one and two weeks. In mild/moderate cases, the positive IgG rate was 17% within one week and 63% between one and two weeks; IgM was positive in 80% and 75% of severe and critical cases, and 42% and 88% of mild/moderate cases, respectively. On the CMIA, no anti-SARS-CoV-2 IgG antibodies were detected in COVID-19 outpatients with mild symptoms within 10 days from onset, whereas 50% of samples from severe inpatients were IgG-positive in the same period. The IC assay detected higher IgM positivity earlier from symptom onset in severe and critical cases than in mild/moderate cases. CONCLUSIONS: A serologic anti-SARS-CoV-2 antibody analysis can complement PCR for diagnosing COVID-19 14 days after symptom onset.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19 , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/metabolism , Adult , Aged , Aged, 80 and over , COVID-19/blood , COVID-19/diagnosis , COVID-19/epidemiology , Female , Humans , Immunoassay , Japan/epidemiology , Male , Middle Aged
14.
Diagnostics (Basel) ; 11(3)2021 Mar 09.
Article in English | MEDLINE | ID: covidwho-1158367

ABSTRACT

SARS-CoV-2 is a zoonotic betacoronavirus associated with worldwide transmission of COVID-19 disease. By the beginning of March, WHO reported about 113,820,000 confirmed cases including more than 2,527,000 deaths all over the world. However, the true extent of virus circulation or its real infection/fatality ratio is not well-estimated due to the huge portion of asymptomatic infections. In this observational study, we have estimated the prevalence of specific immunoglobulin M and G directed towards SARS-CoV-2 antigen in a cohort of 1383 adult volunteers aged over 65 years old, living in the district of Benevento, in the South of Italy. Serological screening was carried out on capillary blood in September 2020, seven months after pandemic outbreak in Italy, to evaluate virus circulation and antibody response among elderly adults, in which severe symptoms due to viral infection are more common. The overall seroprevalence of anti-SARS-CoV-2 antibodies was 4.70% (CI 3.70%-5.95%) with no statistically significant differences between sexes. Among these, 69.69% (CI 55.61%-77.80%) tested positive to IgM, 23.08% (CI 14.51%-34.64%) to IgG and 9.23% (CI 4.30%-18.71%) was positive for both. All patients that were positive to IgM underwent molecular testing through RT-qPCR on oral-rhino pharyngeal swabs and only one specimen was positive for SARS-CoV-2 RNA detection. Instead, the presence of IgG from screened volunteers was confirmed by re-testing serum samples using both an ELISA assay validated for in vitro diagnostic use (IVD) and a recently published synthetic peptide-based ELISA assay. In conclusion, our report suggests that (1) early restrictions were successful in limiting COVID-19 diffusion in the district of Benevento; (2) rapid serological analysis is an ideal testing for both determining real seroprevalence and massive screening, whereas detection of viral RNA remains a gold standard for identification of infected patients; (3) even among people without COVID-19 related symptoms, the antibody response against SARS-CoV-2 antigens has individual features.

15.
Acta Med Port ; 34(2): 87-94, 2021 Feb 01.
Article in English | MEDLINE | ID: covidwho-1110853

ABSTRACT

INTRODUCTION: The aim of this study was to estimate and describe the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific antibodies (immunoglobulin M and/or immunoglobulin G) in Portugal in May-July 2020. MATERIAL AND METHODS: A cross-sectional seroepidemiological survey was developed after the peak of the first epidemic wave on a sample of 2301 Portuguese residents, aged 1 year or older. Survey sample was selected using a two-stage stratified non-probability sampling design (quota sampling). SARS-CoV-2 immunoglobulin M and immunoglobulin G antibodies were measured in serum samples by enzyme-linked immunosorbent assay. Seroprevalence estimates of immunoglobulin M and/or immunoglobulin G and 95% confidence intervals were stratified by sex, age group, health region and education. RESULTS: Overall, seroprevalence was 2.9% (95% confidence interval: 2.0% - 4.2%). Higher prevalence rates were observed in male (4.1%, 95% confidence interval: 2.6% - 6.6%) and those with secondary education (6.4%, 95% confidence interval: 3.2% - 12.5%). Differences in seroprevalence by age group and region were not statistically significant. DISCUSSION: The estimated seroprevalence of SARS-CoV-2 was higher than the cumulative incidence reported by the National Surveillance System but far from necessary to reach herd immunity. CONCLUSION: Our results support limited extent of infection by SARS-CoV-2 in the study population possibly due to early lockdown measures implemented in Portugal and support the need to continue monitoring of SARS-CoV-2 seroprevalence in order to increase our knowledge about the evolution of the epidemic and to estimate the proportion of the susceptible population over time.


Introdução: Este estudo tem como objetivo estimar e descrever a prevalência dos anticorpos específicos (imunoglobulina M e/ou imunoglobulina G) contra o vírus da síndrome respiratória aguda grave do coronavírus 2 (SARS-CoV-2) em Portugal em maio-julho de 2020. Material e Métodos: Após o pico da primeira onda epidémica foi realizado um estudo seroepidemiológico transversal numa amostra de 2301 pessoas residentes em Portugal, com idade igual ou superior a um ano. A amostra foi selecionada recorrendo um desenho amostral não probabilístico bietápico estratificado por quotas. Procedeu-se à deteção de anticorpos específicos contra SARS-CoV-2 (imunoglobulina M e imunoglobulina G) em amostras de soro por ensaio de imunoabsorção enzimática. As estimativas da seroprevalência (imunoglobulina M e/ou imunoglobulina G) e os respetivos intervalos de confiança a 95% foram estratificadas por sexo, grupo etário, região de saúde e escolaridade. Resultados: A seroprevalência de anticorpos específicos imunoglobulina M e/ou imunoglobulina G foi de 2,9 % (intervalo de confiança a 95%: 2,0% ­ 4,2%), tendo sido mais elevada em homens (4,1%, intervalo de confiança a 95%: 2,6% - 6,6%) e nos indivíduos com ensino secundário (6,4%, intervalo de confiança a 95%: 3,2% - 12,5%). Não foram identificadas diferenças estatisticamente significativas na entre os grupos etários estudados, nem entre regiões. Discussão: A seroprevalência estimada foi superior à incidência cumulativa de infeção reportada pelo Sistema Nacional de Vigilância, embora longe dos valores necessários para atingir a imunidade de grupo. Conclusão: Os resultados indicam uma extensão limitada da infeção por SARS-CoV-2, na população estudada compatível com uma implementação precoce das medidas de confinamento em Portugal e suporta a necessidade de monitorização a seroprevalência de SARS-CoV-2 para conhecer a evolução da epidemia e proporção da população suscetível ao longo do tempo.


Subject(s)
Antibodies, Viral/blood , COVID-19/immunology , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/immunology , Adolescent , Adult , Age Distribution , Aged , COVID-19/epidemiology , Child , Child, Preschool , Confidence Intervals , Cross-Sectional Studies , Educational Status , Epidemics , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Portugal/epidemiology , Prevalence , Seroepidemiologic Studies , Sex Distribution , Young Adult
16.
Epidemiol Prev ; 44(5-6 Suppl 2): 200-206, 2020.
Article in Italian | MEDLINE | ID: covidwho-1068140

ABSTRACT

BACKGROUND: to avoid a new spread of the SARS-CoV-2 infection, the post lockdown period requires the implementation of effective strategies for the case finding and contact tracing. The presence of asymptomatic subjects in the population, that are responsible for about 30% of the new infections, may complicate this phase. Serological tests for the measurement of immune response could represent an effective tool for the rapid monitoring of the population with asymptomatic infections and for estimating the proportion of immune in a territory, too. OBJECTIVES: to describe the distribution of the immune response to SARS-CoV-2 infection in the population of the Municipality of Borgosesia (Piedmont Region, Northern Italy) and to estimate the efficacy of this strategy for the identification of asymptomatic cases. DESIGN: Cross-sectional study with administration of a rapid test to assess the seroprevalence of anti-SARS-CoV-2 IgG/IgM antibodies. SETTING AND PARTICIPANTS: all subjects resident in Borgosesia over the age of 18, where invited to participate. A rapid serological test was administered to enrolled participants to detect the presence of SARS-CoV-2 IgG and IgM antibodies on peripheral blood. Subjects with IgG or IgM positivity were offered to perform a swab test for viral RNA research. MAIN OUTCOME MEASURES: the prevalence of IgM and IgG, and the relative risks of having positive swab test and of having symptoms similar to those of COVID-19 in the recent past has been estimated. RESULTS: 4,987 subjects participated to study, 44.5% of the adult population of Borgosesia. The average age was 55 years. There was a greater participation of women (54.4%), of people with a higher education level (37.3%) and of people without specific previous symptoms (95.1%). 245 people had a positive test for IgM or IgG, and the estimated prevalence was of 4.9%. 209 out of 245 subjects who were positive to the rapid test underwent to the RT-PCR test and this allowed to isolate 24 positive subjects. CONCLUSIONS: the seroprevalence values ​​estimated for subjects residing in the city of Borgosesia which underwent the rapid test for the detection of type M and type G antibodies on peripheral blood, confirmed the population-based estimates reported in literature, in particular with the results of the Italian survey of seroprevalence. Furthermore, the implementation of this test allowed the identification and isolation of completely asymptomatic subjects, that could have been identified only through screening with tests for viral RNA.


Subject(s)
Antibodies, Viral/blood , Asymptomatic Infections/epidemiology , COVID-19/epidemiology , Immunoglobulin G/blood , Immunoglobulin M/blood , Pandemics , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , COVID-19 Nucleic Acid Testing , Contact Tracing , Cross-Sectional Studies , Educational Status , Female , Humans , Italy/epidemiology , Male , Middle Aged , Nasopharynx/virology , Population Surveillance , Quarantine , RNA, Viral/analysis , SARS-CoV-2/isolation & purification , Seroepidemiologic Studies , Urban Population , Young Adult
17.
Ocul Surf ; 19: 322-329, 2021 01.
Article in English | MEDLINE | ID: covidwho-1065416

ABSTRACT

BACKGROUND: SARS-CoV-2 is found in conjunctival swabs and tears of COVID-19 patients. However, the presence of SARS-CoV-2 has not been detected in the human eye to date. We undertook this study to analyze the prevalence of SARS-CoV-2 in human post-mortem ocular tissues. METHODS: The expression of SARS-CoV-2 RNA was assessed by RT-PCR in corneal and scleral tissues from 33 surgical-intended donors who were eliminated from a surgical use per Eye Bank Association of America (EBAA) donor screening guidelines or medical director review or positive COVID-19 test. Ocular levels of SARS-CoV-2 RNA (RT-PCR), Envelope and Spike proteins (immunohistochemistry) and anti-SARS-CoV-2 IgG and IgM antibodies (ELISA) in blood were evaluated in additional 10 research-intent COVID-19 positive donors. FINDINGS: Of 132 ocular tissues from 33 surgical-intended donors, the positivity rate for SARS-CoV-2 RNA was ~13% (17/132). Of 10 COVID-19 donors, six had PCR positive post-mortem nasopharyngeal swabs whereas eight exhibited positive post-mortem anti-SARS-CoV-2 IgG levels. Among 20 eyes recovered from 10 COVID-19 donors: three conjunctival, one anterior corneal, five posterior corneal, and three vitreous swabs tested positive for SARS-CoV-2 RNA. SARS-CoV-2 spike and envelope proteins were detected in epithelial layer of the corneas that were procured without Povidone-Iodine (PVP-I) disinfection. INTERPRETATIONS: Our study showed a small but noteworthy prevalence of SARS-CoV-2 in ocular tissues from COVID-19 donors. These findings underscore the criticality of donor screening guidelines, post-mortem nasopharyngeal PCR testing and PVP-I disinfection protocol to eliminate any tissue harboring SARS-CoV-2 being used for corneal transplantation.


Subject(s)
Autopsy , COVID-19 , Conjunctiva/virology , RNA, Viral/isolation & purification , SARS-CoV-2/isolation & purification , Aged , Cornea/virology , Female , Humans , Male , Middle Aged , Prevalence , Vitreous Body/virology
18.
Int J Infect Dis ; 104: 159-163, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1065183

ABSTRACT

OBJECTIVES: Aside from the outbreak of the coronavirus disease 2019 (COVID-19), serological tests are not well known for their diagnostic value. We assessed the performance of serological tests using stored sera from patients with a variety of pathologic conditions, collected before the 2020 pandemic in Italy. METHODS: Rapid lateral flow tests and Enzyme-Linked Immunosorbent Assays (ELISA) that detect Immunoglobulin M (IgM) and Immunoglobulin G (IgG) antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were carried out using 1150 stored human serum samples that had been collected in 2018 and 2019. The tests were also run using samples from 15 control patients who had positive or negative oral swab test results, as assessed using real-time reverse transcription-polymerase chain reaction (rRT-PCR). The urea dissociation test was employed to rule out false-positive reactivity in the two antibody detection methods. RESULTS: The lateral flow tests revealed 21 positive samples from the stored sera: 12 for IgM, four for IgG, and five for IgM/IgG. Among the nine rRT-PCR- positive controls, six individuals presented IgG and three IgM/IgG positivity. Using the urea (6 mol/L) dissociation test, two of the twelve stored samples that had shown IgM positivity were confirmed to be positive. The ELISA test detected four IgM-positive and three IgG-positive specimens. After treatment with 4 mol/L urea, the IgM-positive samples became negative, whereas the IgG positivity persisted. All of the rRT-PCR-positive controls were found to retain IgM or IgG positivity following the urea treatment. CONCLUSIONS: Our findings highlight the limited utility of serological testing for the SARS-CoV-2 virus based on the results of specimens collected before the outbreak of the infection.


Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19/virology , COVID-19 Serological Testing , Enzyme-Linked Immunosorbent Assay , False Positive Reactions , Female , Humans , Italy/epidemiology , Male , Middle Aged , Pandemics , Retrospective Studies , Young Adult
19.
Clin Exp Med ; 21(3): 361-367, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1064526

ABSTRACT

BACKGROUND: The recurrence of positive SARS-CoV-2 RT-PCR is frequently found in discharged COVID-19 patients but its clinical significance remains unclear. The potential cause, clinical characteristics and infectiousness of the recurrent positive RT-PCR patients need to be answered. METHODS: A single-centered, retrospective study of 51 discharged COVID-19 patients was carried out at a designated hospital for COVID-19. The demographic data, clinical records and laboratory findings of 25 patients with recurrent positive RT-PCR from hospitalization to follow-up were collected and compared to 26 patients with negative RT-PCR discharged regularly during the same period. Discharged patients' family members and close contacts were also interviewed by telephone to evaluate patients' potential infectiousness. RESULTS: The titer of both IgG and IgM antibodies was significantly lower (p = 0.027, p = 0.011) in patients with recurrent positive RT-PCR. Median duration of viral shedding significantly prolonged in patients with recurrent positive RT-PCR (36.0 days vs 9.0 days, p = 0.000). There was no significant difference in demographic features, clinical features, lymphocyte subsets count and inflammatory cytokines levels between the two groups of patients. No fatal case was noted in two groups. As of the last day of follow-up, none of the discharged patients' family members or close contact developed any symptoms of COVID-19. CONCLUSIONS: Patients with low levels of IgG and IgM are more likely to have recurrent positive SARS-CoV-2 RT-PCR results and lead to a prolonged viral shedding. The recurrent positive of SARS-CoV-2 RT-PCR may not indicate the recurrence or aggravation of COVID-19. The detection of SARS-CoV-2 by RT-PCR in the patients recovered from COVID-19 is not necessarily correlated with the ability of transmission.


Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , RNA, Viral/genetics , Reinfection/virology , SARS-CoV-2/isolation & purification , Adult , COVID-19/blood , COVID-19/immunology , Case-Control Studies , China , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Patient Discharge , Retrospective Studies , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Time Factors , Virus Shedding
20.
JAMA Pediatr ; 175(6): 594-600, 2021 06 01.
Article in English | MEDLINE | ID: covidwho-1052819

ABSTRACT

Importance: Maternally derived antibodies are a key element of neonatal immunity. Understanding the dynamics of maternal antibody responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy and subsequent transplacental antibody transfer can inform neonatal management as well as maternal vaccination strategies. Objective: To assess the association between maternal and neonatal SARS-CoV-2-specific antibody concentrations. Design, Setting, and Participants: This cohort study took place at Pennsylvania Hospital in Philadelphia, Pennsylvania. A total of 1714 women delivered at the study site between April 9 and August 8, 2020. Maternal and cord blood sera were available for antibody measurement for 1471 mother/newborn dyads. Exposures: SARS-CoV-2. Main Outcomes and Measures: IgG and IgM antibodies to the receptor-binding domain of the SARS-CoV-2 spike protein were measured by enzyme-linked immunosorbent assay. Antibody concentrations and transplacental transfer ratios were analyzed in combination with demographic and clinical data. Results: The study cohort consisted of 1714 parturient women, with median (interquartile range) age of 32 (28-35) years, of whom 450 (26.3%) identified as Black/non-Hispanic, 879 (51.3%) as White/non-Hispanic, 203 (11.8%) as Hispanic, 126 (7.3%) as Asian, and 56 (3.3%) as other race/ethnicity. Among 1471 mother/newborn dyads for which matched sera were available, SARS-CoV-2 IgG and/or IgM antibodies were detected in 83 of 1471 women (6%; 95% CI, 5%-7%) at the time of delivery, and IgG was detected in cord blood from 72 of 83 newborns (87%; 95% CI, 78%-93%). IgM was not detected in any cord blood specimen, and antibodies were not detected in any infant born to a seronegative mother. Eleven infants born to seropositive mothers were seronegative: 5 of 11 (45%) were born to mothers with IgM antibody only, and 6 of 11 (55%) were born to mothers with significantly lower IgG concentrations compared with those found among mothers of seropositive infants. Cord blood IgG concentrations were positively correlated with maternal IgG concentrations (r = 0.886; P < .001). Placental transfer ratios more than 1.0 were observed among women with asymptomatic SARS-CoV-2 infections as well as those with mild, moderate, and severe coronavirus disease 2019. Transfer ratios increased with increasing time between onset of maternal infection and delivery. Conclusions and Relevance: In this cohort study, maternal IgG antibodies to SARS-CoV-2 were transferred across the placenta after asymptomatic as well as symptomatic infection during pregnancy. Cord blood antibody concentrations correlated with maternal antibody concentrations and with duration between onset of infection and delivery. Our findings demonstrate the potential for maternally derived SARS-CoV-2 specific antibodies to provide neonatal protection from coronavirus disease 2019.


Subject(s)
COVID-19/immunology , Pregnancy Complications, Infectious/immunology , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/blood , Adult , Antibodies, Viral/blood , Cohort Studies , Enzyme-Linked Immunosorbent Assay , Female , Fetal Blood/immunology , Humans , Immunoglobulin G/blood , Infant, Newborn , Infectious Disease Transmission, Vertical/prevention & control , Pregnancy
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