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1.
Am J Trop Med Hyg ; 105(2): 395-400, 2021 Jun 17.
Article in English | MEDLINE | ID: covidwho-1374604

ABSTRACT

Data on the longevity of humoral and cell-mediated immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with coronavirus disease 2019 (COVID-19) are limited. We evaluated the detailed kinetics of antibody and T-cell responses at the acute, convalescent, and post-convalescent phases in COVID-19 patients with a wide range of severity. We enrolled patients with COVID-19 prospectively from four hospitals and one community treatment center between February 2020 and January 2021. symptom severity was classified as mild, moderate, or severe/critical. Patient blood samples were collected at 1 week (acute), 1 month (convalescent), and 2 months after symptom onset (post-convalescent). Human SARS-CoV-2 IgG and IgM antibodies were measured using in-house-developed ELISA. The SARS-CoV-2-specific T-cell responses against overlapping peptides of spike proteins and nucleoprotein were measured by interferon-γ enzyme-linked immunospot assays. Twenty-five COVID-19 patients were analyzed (mild, n = 5; moderate, n = 9; severe/critical, n = 11). IgM and IgG antibody responses peaked at 1 month after symptom onset and decreased at 2 months. IgG response levels were significantly greater in the severe/critical group compared with other groups. Interferon-γ-producing T-cell responses increased between 1 week and 1 month after symptom onset, and had a trend toward decreasing at 2 months, but did not show significant differences according to severity. Our data indicate that SARS-CoV-2-specific antibody responses were greater in those with severe symptoms and waned after reaching a peak around 1 month after symptom onset. However, SARS-CoV-2-specific T-cell responses were not significantly different according to symptom severity, and decreased slowly during the post-convalescent phase.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Severity of Illness Index , T-Lymphocytes/immunology , Acute Disease , Adult , Aged , Antibodies, Neutralizing/blood , COVID-19/blood , COVID-19/pathology , Convalescence , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Interferon-gamma/analysis , Kinetics , Male , Middle Aged , Prospective Studies
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.
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.

4.
Mikrobiyol Bul ; 55(2): 207-222, 2021 Apr.
Article in Turkish | MEDLINE | ID: covidwho-1197632

ABSTRACT

Following the emergence of severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) and using only PCR for diagnosis, antibody tests have been rapidly developed by various commercial companies. There are differences between the sensitivity and specificity of these tests due to the usage of different viral target proteins and antibody subclasses. In order to evaluate the diagnostic use of these tests, we aimed to examine the diagnostic performance, especially sensitivity and specificity, of SARS-CoV-2 IgM, IgA and IgG tests of various companies (Abbott, Roche, Euroimmun, Dia.Pro, Anshlabs, Vircell, UnScience and RedCell), which have different principles (ECLIA/CLIA, EIA, LFA). Current (n= 180) and past (n= 180) COVID-19 patients with clinical and molecular diagnosis of COVID-19 admitted to Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine Hospital, Pandemic Polyclinic with suspected COVID-19 infection, were included in our study. The patients admitted within the first 3 weeks after the onset of symptoms were included in the current patient group, and those admitted at the third and after the third week were included in the past patient group. Serum samples (n= 180) obtained from Istanbul Sisli Hamidiye Etfal Training and Research Hospital, Blood Center between April and June 2018 before the COVID-19 pandemic were included in the study as a control group. All the tests included in our study were studied with the recommendations of the manufacturer companies. Between the IgG detection tests with different principles in patients with past COVID-19, the sensitivity and specificity values of the most effective tests were; 86.7%/99.4% (Abbott), 86.1%/98.9% (Dia.Pro), 91.3%/95% (RedCell). Between the IgM detection tests with different principles in current COVID-19 patients, the sensitivity and specificity values were; 67.8%/99.4% (Abbott), 68.9%/98.6% (Vircell), 50%/97.5% (RedCell). Abbott IgM with a kappa coefficient of 0.67 and Vircell IgM + IgA test with a kappa coefficient of 0.65 showed the best fit in patients with current COVID-19 infection. In patients with past COVID-19, Abbott IgG with 0.86 kappa coefficient and Dia.Pro IgG test with 0.85 kappa coefficient showed the best match. Due to the low sensitivity of IgM detection antibody tests, they should not be preferred instead of real-time reverse transcriptase polymerase chain reaction in routine diagnosis. IgG detection tests may be preferred to detect the antibody response and the titers in people who have had COVID-19 for population seroprevalence and especially therapeutic immune plasma production. However, it is thought that the combined use of both ECLIA/CLIA-based and EIA/ELISA-based tests together may be more effective in routine use for SARS-CoV-2 IgG tests.


Subject(s)
COVID-19 , Coronavirus Infections , Antibodies, Viral , Humans , Immunoglobulin M , Pandemics , SARS-CoV-2 , Sensitivity and Specificity , Seroepidemiologic Studies
5.
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
6.
Ir J Med Sci ; 191(1): 31-37, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1086658

ABSTRACT

KEY POINTS: In our clinical cross-sectional study, we identified 107 of 347 patients who were tested positive for antibodies of novel Coronavirus 2019 (SARS-CoV-2). Main symptoms were exhaustion and cough, exposition to other COVID-19-patients appeared frequently. BACKGROUND: There is urgent need for information on predictive parameters on immunity and infectivity in Coronavirus disease-2019 (COVID-19) pandemic. Our aim was to investigate distribution of novel Coronavirus 2019 (SARS-CoV-2) infections in a German General Practice and to learn about possible predictive parameters regarding infection and pathways of transmission. METHODS: In our cross-sectional study, we tested 347 patients of our General Practice using 2019-nCoV-2-IgG/IgM antibody test [2019-nCoV2 IgG/IgM Rapid Test Cassette (Ref.: INCP-402/INCP-402B; ACRO, BIOTECH, INC.)]. We asked for 13 specific symptoms and 4 questions to investigate patients' surroundings. RESULTS: A total of 107 of 347 patients were tested positive for antibodies (Immunoglobulin M-positive and/or Immunoglobulin G-positive). In antibody-positive group, body aches and rhinorrhea were seen more often and there were significantly less asymptomatic patients. Stay in area of risk was significantly more frequent in antibody-positive group as well as contact to infected persons. Distribution of other symptoms was not significantly different between both groups. Most adults or children with SARS-CoV-2 infection presented with mild flu-like symptoms. CONCLUSION: A total of 30% of patients had antibodies. It was not possible to identify one solid predictive symptom. Serological testing may be helpful for the diagnosis of suspected patients with negative RT-PCR results and for the identification of asymptomatic infections.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antibodies, Viral , Child , Cross-Sectional Studies , Family Practice , Humans , Pandemics , Sensitivity and Specificity
7.
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
8.
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
9.
Diagn Microbiol Infect Dis ; 99(4): 115300, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1002475

ABSTRACT

The clinical and public health utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing requires a better understanding of the dynamics of the humoral response to infection. To track seroconversion of IgG and IgM antibodies in patients with SARS-CoV-2 infection and its association with patient and clinical factors and outcomes. Residual patient specimens were analyzed on the Abbott ARCHITECT i2000 instrument using the Abbott SARS-CoV-2 IgG assay and prototype SARS-CoV-2 IgM assay. Age, sex, comorbidities, symptom onset date, mortality, and specimen collection date were obtained from electronic medical records. Three hundred fifty-nine longitudinal samples were collected from 89 hospitalized patients 0 to 82 days postsymptom onset. Of all, 51.7% of the patients developed IgG and IgM antibodies simultaneously; 32.8% seroconverted for IgM before IgG. On average, patients seroconverted for IgG by 8 days and for IgM by 7 days postsymptom onset. All patients achieved IgG seropositivity by 19 days and IgM seropositivity by 17 days. Median time to IgG and IgM seroconversion was prolonged and initial levels of IgG were lower in immunocompromised patients and patients <65 years of age compared to immune competent patients and those ≥65 years of age. Immunocompromised patients also had persistently lower levels of IgM that peaked on day 17.6 and decreased thereafter compared to immune competent patients. IgM seroconversion in patients who died reached significantly higher levels later after symptom onset than in those who recovered. SARS-CoV-2 infected patients have similar time to seroconversion for IgG and IgM. However, differences in immune status and age alter time to seroconversion. These results may help guide serologic testing application in COVID-19 management.


Subject(s)
Antibodies, Viral/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/immunology , Seroconversion , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19 Serological Testing/methods , Female , Hospitalization , Humans , Immunity, Humoral/immunology , Longitudinal Studies , Male , Middle Aged , Sensitivity and Specificity , United States , Young Adult
10.
Front Microbiol ; 11: 597529, 2020.
Article in English | MEDLINE | ID: covidwho-1000110

ABSTRACT

BACKGROUND: The SARS-CoV-2 outbreak has emerged at the end of 2019. Aside from the detection of viral genome with specific RT-PCR, there is a growing need for reliable determination of the serological status. We aimed at evaluating five SARS-CoV-2 serology assays. METHODS: An in-house immunofluorescence assay (IFA), two ELISA kits (EUROIMMUN® ELISA SARS-CoV-2 IgG and NovaLisa® SARS-CoV-2 IgG and IgM) and two lateral flow assays (T-Tek® SARS-CoV-2 IgG/IgM Antibody Test Kit and Sure Bio-tech® SARS-CoV-2 IgM/IgG Antibody Rapid Test) were compared on 40 serums from RT-PCR-confirmed SARS-CoV-2 infected patients and 10 SARS-CoV-2 RT-PCR negative subjects as controls. RESULTS: Control subjects tested negative for SARS-CoV-2 antibodies with all five systems. Estimated sensitivities varied from 35.5 to 71.0% for IgG detection and from 19.4 to 64.5% for IgM detection. For IgG, in-house IFA, EuroImmun, T-Tek and NovaLisa displayed 50-72.5% agreement with other systems except IFA vs EuroImmun and T-Tek vs NovaLisa. Intermethod agreement for IgM determination was between 30 and 72.5%. DISCUSSION: The overall intermethod agreement was moderate. This inconsistency could be explained by the diversity of assay methods, antigens used and immunoglobulin isotype tested. Estimated sensitivities were low, highlighting the limited value of antibody detection in CoVID-19. CONCLUSION: Comparison of five systems for SARS-CoV-2 IgG and IgM antibodies showed limited sensitivity and overall concordance. The place and indications of serological status assessment with currently available tools in the CoVID-19 pandemic need further evaluations.

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