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1.
Nat Commun ; 12(1): 1383, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33654063

RESUMEN

In this study, we investigate the seroprevalence of SARS-CoV-2 antibodies among blood donors in the cities of Wuhan, Shenzhen, and Shijiazhuang in China. From January to April 2020, 38,144 healthy blood donors in the three cities were tested for total antibody against SARS-CoV-2 followed by pseudotype SARS-CoV-2 neutralization tests, IgG, and IgM antibody testing. Finally, a total of 398 donors were confirmed positive. The age- and sex-standardized SARS-CoV-2 seroprevalence among 18-60 year-old adults (18-65 year-old in Shenzhen) was 2.66% (95% CI: 2.24%-3.07%) in Wuhan, 0.033% (95% CI: 0.0029%-0.267%) in Shenzhen, and 0.0028% (95% CI: 0.0001%-0.158%) in Shijiazhuang, respectively. Female sex and older-age were identified to be independent risk factors for SARS-CoV-2 seropositivity among blood donors in Wuhan. As most of the population of China remained uninfected during the early wave of the COVID-19 pandemic, effective public health measures are still certainly required to block viral spread before a vaccine is widely available.


Asunto(s)
/patogenicidad , Anticuerpos Antivirales/sangre , Donantes de Sangre/estadística & datos numéricos , /epidemiología , China/epidemiología , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Pruebas de Neutralización , Prevalencia , Factores de Riesgo , /inmunología
2.
BMC Infect Dis ; 21(1): 305, 2021 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-33765968

RESUMEN

BACKGROUND: Iranian children were vaccinated with the scheduled two doses of monovalent measles vaccine (mMV) from 1984. In December 2003, a nationwide campaign of measles-rubella (MR) immunization was established to vaccinate 5-25 year- old individuals. In 2004, the mMV was replaced with measles- mumps- rubella (MMR) vaccine. Despite the high vaccination coverage, the outbreaks of measles still occur in the country. In this Study, the MR immunity status of various age groups, vaccinated with different schedules was investigated, and the immunologic response of seronegative subjects to revaccination was examined. METHODS: This cross-sectional study was conducted among 7-33-year-old healthy individuals with a documented history of measles vaccination from November 2017 to June 2018. The subjects were categorized as follows: group A, including 20-33 year-old individuals; vaccinated with 1-2 doses of mMV at ages 9 and 15 months, and revaccinated with MR, group B, including 15-19-year-old individuals, vaccinated with two doses of mMV at 9 and 15 months of age, and received additional dose of MMR upon school entrance, group C, including 11-14 year-old individuals, vaccinated with two-doses of MMR at the ages of 15 months and 6 years, and group D, including 7-10 year-old individuals vaccinated with two-doses of MMR vaccine at the ages 12 and 18 months, respectively. Levels of antimeasles- antirubella IgG antibodies in the collected sera were measured. Also antimeasles- antirubella IgM and IgG of seronegative individuals were reexamined at 4-6 weeks after MMR revaccination. The collected data were analyzed using descriptive statistical methods. RESULTS: A total of 635 individuals were investigated in this study. Group A, 98; group B, 295; group C, 139; and group D, 103 persons. Overall, 12.3 and 18.4% of the population were seronegative for measles and rubella antibodies. This rate varied greatly between the 4 groups: group A, 0/0-2%; group B,15.2-25.0%; group C,11.5-17.2%; and groupD,14.6-18.4%. After revaccination, 92 and 94.9% of seronegative individuals showed IgG response to measles and rubella vaccines, respectively. CONCLUSION: Despite the high coverage rate of M-R containing vaccines, a significant number of vaccinated subjects were seronegative for measles and rubella, possibly because of secondary vaccine failure; this may negatively affect measles-rubella elimination targets in the country. If these findings are confirmed in similar future studies, a more robust regional/national supplementary immunization activity will be considered.


Asunto(s)
Anticuerpos Antivirales/sangre , Vacuna contra el Sarampión-Parotiditis-Rubéola/inmunología , Sarampión/prevención & control , Rubéola (Sarampión Alemán)/prevención & control , Adolescente , Adulto , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Esquemas de Inmunización , Inmunización Secundaria , Inmunoglobulina G/sangre , Irán , Masculino , Sarampión/inmunología , Rubéola (Sarampión Alemán)/inmunología , Adulto Joven
3.
Euro Surveill ; 26(12)2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33769252

RESUMEN

Sera were collected from 185 adults aged ≥ 70 years in London to evaluate the immune response to COVID-19 vaccines. A single dose of Pfizer/BioNtech vaccine resulted in > 94% seropositivity after 3 weeks in naïve individuals using the Roche Spike antibody assay, while two doses produced very high spike antibody levels, significantly higher than convalescent sera from mild-to-moderate PCR-confirmed adult cases. Our findings support the United Kingdom's approach of prioritising the first dose and delaying the second dose of COVID-19 vaccine.


Asunto(s)
Anticuerpos Antivirales/sangre , Formación de Anticuerpos , /prevención & control , Anciano , Anciano de 80 o más Años , Humanos , Londres
4.
EBioMedicine ; 65: 103259, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33662833

RESUMEN

BACKGROUND: SARS-CoV-2 serology is used to identify prior infection at individual and at population level. Extended longitudinal studies with multi-timepoint sampling to evaluate dynamic changes in antibody levels are required to identify the time horizon in which these applications of serology are valid, and to explore the longevity of protective humoral immunity. METHODS: Healthcare workers were recruited to a prospective cohort study from the first SARS-CoV-2 epidemic peak in London, undergoing weekly symptom screen, viral PCR and blood sampling over 16-21 weeks. Serological analysis (n =12,990) was performed using semi-quantitative Euroimmun IgG to viral spike S1 domain and Roche total antibody to viral nucleocapsid protein (NP) assays. Comparisons were made to pseudovirus neutralizing antibody measurements. FINDINGS: A total of 157/729 (21.5%) participants developed positive SARS-CoV-2 serology by one or other assay, of whom 31.0% were asymptomatic and there were no deaths. Peak Euroimmun anti-S1 and Roche anti-NP measurements correlated (r = 0.57, p<0.0001) but only anti-S1 measurements correlated with near-contemporary pseudovirus neutralising antibody titres (measured at 16-18 weeks, r = 0.57, p<0.0001). By 21 weeks' follow-up, 31/143 (21.7%) anti-S1 and 6/150 (4.0%) anti-NP measurements reverted to negative. Mathematical modelling revealed faster clearance of anti-S1 compared to anti-NP (median half-life of 2.5 weeks versus 4.0 weeks), earlier transition to lower levels of antibody production (median of 8 versus 13 weeks), and greater reductions in relative antibody production rate after the transition (median of 35% versus 50%). INTERPRETATION: Mild SARS-CoV-2 infection is associated with heterogeneous serological responses in Euroimmun anti-S1 and Roche anti-NP assays. Anti-S1 responses showed faster rates of clearance, more rapid transition from high to low level production rate and greater reduction in production rate after this transition. In mild infection, anti-S1 serology alone may underestimate incident infections. The mechanisms that underpin faster clearance and lower rates of sustained anti-S1 production may impact on the longevity of humoral immunity. FUNDING: Charitable donations via Barts Charity, Wellcome Trust, NIHR.


Asunto(s)
Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , /inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Personal de Salud/estadística & datos numéricos , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Fosfoproteínas/inmunología , Dominios Proteicos/inmunología
5.
Emerg Microbes Infect ; 10(1): 629-637, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33691606

RESUMEN

COVID-19 vaccines emerging from different platforms differ in efficacy, duration of protection, and side effects. To maximize the benefits of vaccination, we explored the utility of employing a heterologous prime-boost strategy in which different combinations of the four types of leading COVID-19 vaccine candidates that are undergoing clinical trials in China were tested in a mouse model. Our results showed that sequential immunization with adenovirus vectored vaccine followed by inactivated/recombinant subunit/mRNA vaccine administration specifically increased levels of neutralizing antibodies and promoted the modulation of antibody responses to predominantly neutralizing antibodies. Moreover, a heterologous prime-boost regimen with an adenovirus vector vaccine also improved Th1-biased T cell responses. Our results provide new ideas for the development and application of COVID-19 vaccines to control the SARS-CoV-2 pandemic.


Asunto(s)
Vacunas contra el Adenovirus/inmunología , Anticuerpos Antivirales/sangre , Inmunización Secundaria/métodos , Vacunas de Subunidad/inmunología , Vacunas Sintéticas/inmunología , Vacunas contra el Adenovirus/administración & dosificación , Animales , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , /efectos adversos , Interferón gamma/sangre , Recuento de Linfocitos , Ratones , Ratones Endogámicos BALB C , Linfocitos T/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Vacunación/efectos adversos , Vacunas de Subunidad/administración & dosificación , Vacunas Sintéticas/administración & dosificación
6.
PLoS Pathog ; 17(3): e1009413, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33705496

RESUMEN

SARS-CoV-2 virus is transmitted in closed settings to people in contact with COVID-19 patients such as healthcare workers and household contacts. However, household person-to-person transmission studies are limited. Households participating in an ongoing cohort study of influenza incidence and prevalence in rural Egypt were followed. Baseline enrollment was done from August 2015 to March 2017. The study protocol was amended in April 2020 to allow COVID-19 incidence and seroprevalence studies. A total of 290 households including 1598 participants were enrolled and followed from April to October 2020 in four study sites. When a participant showed respiratory illness symptoms, a serum sample and a nasal and an oropharyngeal swab were obtained. Swabs were tested by RT-PCR for SARS-CoV-2 infection. If positive, the subject was followed and swabs collected on days three, six, nine, and 14 after the first swab day and a serum sample obtained on day 14. All subjects residing with the index case were swabbed following the same sampling schedule. Sera were collected from cohort participants in October 2020 to assess seroprevalence. Swabs were tested by RT-PCR. Sera were tested by Microneutralization Assay to measure the neutralizing antibody titer. Incidence of COVID-19, household secondary attack rate, and seroprevalence in the cohort were determined. The incidence of COVID-19 was 6.9% and the household secondary attack rate was 89.8%. Transmission within households occurred within two-days of confirming the index case. Infections were asymptomatic or mild with symptoms resolving within 10 days. The majority developed a neutralizing antibody titer by day 14 post onset. The overall seroprevalence among cohort participants was 34.8%. These results suggest that within-household transmission is high in Egypt. Asymptomatic or mild illness is common. Most infections seroconvert and have a durable neutralizing antibody titer.


Asunto(s)
Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , /transmisión , Adolescente , Adulto , /epidemiología , Niño , Estudios de Cohortes , Egipto/epidemiología , Familia , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , /inmunología , Estudios Seroepidemiológicos , Adulto Joven
7.
Virol J ; 18(1): 52, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33750394

RESUMEN

BACKGROUND: Efficient monitoring and control of coronavirus disease 2019 (COVID-19) require access to diagnostic tests, and serological diagnostic testing is desirable. In the current study, antibodies were investigated in patients recently diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: Cross-sectional data were obtained from 245 patients in whom SARS-CoV-2 infection had been confirmed via real-time reverse transcriptase-polymerase chain reaction between March and October 2020. Serum samples were acquired between 2 and 60 days following the onset of COVID-19 symptoms or the first detection of SARS-CoV-2 in asymptomatic patients. All specimens were tested simultaneously using an IgM/IgG rapid diagnostic test (RDT), IgG nucleocapsid protein-based chemiluminescent microparticle immunoassay (CMIA), IgG, and IgA spike protein-based enzyme-linked immunosorbent assays (ELISAs). Blood donor samples obtained in 2018 were used as negative controls. RESULTS: The sensitivity and specificity of the RDT IgG were compared with the IgG immunoassays as standards. The RDT IgG exhibited 97.5% sensitivity and 89.4% specificity compared with a CMIA IgG, 98.4% sensitivity, and 78.8% specificity compared with an ELISA IgG. IgM, IgG, and IgA seropositivity rates were low between 1 and 2 weeks after COVID-19 symptom onset or the detection of SARS-CoV-2 RNA. IgM seropositivity rate began decreasing after 4 weeks, whereas IgG and IgA seropositivity rate remained at appreciable levels over the 8-week study period. No cross-reactivity with seasonal coronaviruses was detected. CONCLUSIONS: IgG RDT alone or combined with molecular diagnostic tests may be useful for identifying recent SARS-CoV-2 infection.


Asunto(s)
Anticuerpos Antivirales/sangre , /diagnóstico , /aislamiento & purificación , Antígenos Virales/inmunología , Infecciones Asintomáticas/epidemiología , /normas , Estudios Transversales , Humanos , Inmunoensayo , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , /inmunología
9.
Cell Rep ; 34(10): 108837, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33662255

RESUMEN

Passive transfer of convalescent plasma or serum is a time-honored strategy for treating infectious diseases. Human convalescent plasma containing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently being used to treat patients with coronavirus disease 2019 where clinical efficacy trials are ongoing. Here, we assess therapeutic passive transfer in groups of SARS-CoV-2-infected African green monkeys with convalescent sera containing either high or low anti-SARS-CoV-2 neutralizing antibody titers. Differences in viral load and pathology are minimal between monkeys that receive the lower titer convalescent sera and untreated controls. However, lower levels of SARS-CoV-2 in respiratory compartments, reduced severity of virus-associated lung pathology, and reductions in coagulopathy and inflammatory processes are observed in monkeys that receive high titer sera versus untreated controls. Our data indicate that convalescent plasma therapy in humans may be an effective strategy provided that donor sera contain high anti-SARS-CoV-2 neutralizing titers given in early stages of the disease.


Asunto(s)
/terapia , Enfermedades de los Primates/terapia , Enfermedades de los Primates/virología , /inmunología , Animales , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , /virología , Chlorocebus aethiops/inmunología , Femenino , Inmunización Pasiva/métodos , Inmunización Pasiva/veterinaria , Masculino , Enfermedades de los Primates/inmunología , Primates/inmunología , Carga Viral
10.
Acta Biomed ; 92(1): e2021070, 2021 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-33682801

RESUMEN

BACKGROUND AND AIM: The COVID-19 is an infectious disease caused by the novel coronavirus SARS-CoV-2, declared a public health emergency by the World Health Organization. In this study, we evaluated the seroconversion of SARS-CoV-2 antibodies to find predictors of infection in terms of symptoms, health status, and professions. METHODS: Serological samples of 341 volunteers in a cohort in Marche Region, Italy, were analyzed for the presence of IgM and/or IgG immunoglobulins specific for the SARS-CoV-2. Contextually, an anamnestic questionnaire was administered. The binary logistic regression analysis was used to find the predictors of seroconversion. RESULTS: Forty-nine subjects (14.4 %) were found positive, without significant differences between gender and age groups. The predictors identified inside the variable categories "symptoms," "risk factors" (smoking habit and established pathologies), and "professions" were the loss of taste and smell (OR, 8.563), cardiovascular diseases (OR, 2.912), and policeman profession (OR, 3.875), respectively. CONCLUSIONS: Although the limited number of subjects recruited in this study, our results could give important findings to be considered for planning preventive strategies in the view of the next COVID-19 waves.


Asunto(s)
Anticuerpos Antivirales/sangre , /inmunología , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Italia/epidemiología , Masculino , Persona de Mediana Edad , Estudios Seroepidemiológicos , Adulto Joven
11.
BMC Infect Dis ; 21(1): 288, 2021 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-33743628

RESUMEN

BACKGROUND: Many clinicians are aware that certain therapies administered to their patients can have downstream consequences in the form of clinical laboratory test interferences. This is particularly true of laboratory tests that depend on, or directly involve the use of, antibody-based methodology. Intravenously-administered immunoglobulin therapy is one such treatment that can in theory directly impact the results of particular tests in the area of viral serology. This study can help serve as a reference for clinicians researching the impact of intravenously-administered immunoglobulin therapy in the context of positive results that do not reflect the clinical background of the patient. CASE PRESENTATION: We describe a case whereby an intravenously-administered immunoglobulin therapy led to a series of clinical false positives in viral serology, inconsistent with the known patient history as well as recent laboratory results. The patient presented to hospital with petechiae-type bleeding rashes and was investigated for thrombocytopenia after initial blood investigations indicated very low platelets. Subsequent testing of the potential causes for low-platelet involved several viral serology investigations, including hepatitis, cytomegalovirus and human immunodeficiency virus. Initial testing indicated patient exhibited negative status for all viral antibodies and antigens (except immunity for hepatitis B surface antigen antibody). As part of the thrombocytopenia treatment, intravenously-administered immunoglobulin therapy was administered, and subsequent viral serology was ordered. These investigations indicated a positive status for several hepatitis antibodies as well as cytomegalovirus. CONCLUSIONS: This case study illustrates the potential for improper diagnosis of previous or ongoing infection status in patients administered IVIg therapy. Caution should be exercised particularly when interpreting results involving cytomegalovirus and hepatitis.


Asunto(s)
Anticuerpos Antivirales/sangre , Reacciones Falso Positivas , Inmunoglobulinas Intravenosas/uso terapéutico , Adulto , Citomegalovirus , Femenino , Anticuerpos Antihepatitis/sangre , Virus de Hepatitis , Humanos
12.
PLoS One ; 16(3): e0248729, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33725025

RESUMEN

BACKGROUND: As COVID-19 vaccines become available, screening individuals for prior COVID-19 infection and vaccine response in point-of-care (POC) settings has renewed interest. We prospectively screened at-risk individuals for SARS-CoV-2 spike and nucleocapsid protein antibodies in a POC setting to determine if it was a feasible method to identify antibody from prior infection. METHODS: Three EUA-approved lateral flow antibody assays were performed on POC finger-stick blood and compared with serum and a CLIA nucleocapsid antibody immunoassay. Variables including antibody class, time since PCR, and the assay antigen used were evaluated. RESULTS: 512 subjects enrolled, of which 104 had a COVID-19 history and positive PCR. Only three PCR-positive subjects required hospitalization, with one requiring mechanical ventilation. The POC results correlated well with the immunoassay (93-97% sensitivity) and using serum did not improve the sensitivity or specificity. CONCLUSIONS: Finger-stick, POC COVID-19 antibody testing was highly effective in identifying antibody resulting from prior infections in mildly symptomatic subjects. Using high-complexity serum immunoassays did not improve the screening outcome. Almost all individuals with COVID-19 infection produced detectable antibodies to the virus. POC antibody testing is useful as a screen for prior COVID-19 infection, and should be useful in assessing vaccine response.


Asunto(s)
/diagnóstico , Sistemas de Atención de Punto , Adulto , Anciano , Anticuerpos Antivirales/sangre , Femenino , Humanos , Inmunoensayo , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Nucleocápside/inmunología , Juego de Reactivos para Diagnóstico , /aislamiento & purificación , Sensibilidad y Especificidad , Adulto Joven
13.
Viruses ; 13(2)2021 02 11.
Artículo en Inglés | MEDLINE | ID: mdl-33670182

RESUMEN

The coronavirus disease 2019 (Covid-19) pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and presents a global health emergency that needs urgent intervention. Viruses constantly change through mutation, and new variants of a virus are expected to occur over time. In the United Kingdom (UK), a new variant called B.1.1.7 has emerged with an unusually large number of mutations. The aim of this study is to evaluate the level of protection of sera from 12 patients infected and later healed in Apulia Region (Italy) with Covid-19 between March and November 2020, when the English variant was not circulating in this territory yet, against the new VOC 202012/01 variant by seroneutralization assay. The sera of patients had already been tested before, using a virus belonging to the lineage B.1 and showed an antibody neutralizing titer ranging between 1:160 and 1:320. All the 12 sera donors confirmed the same titers of neutralizing antibodies obtained with a strain belonging to the lineage B.1.1.7 (VOC 202012/01). These data indicate that antibodies produced in subjects infected with variants of Sars-CoV-2 strain before the appearance of the English one, seem to have a neutralizing power also against this variant.


Asunto(s)
Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , /inmunología , Animales , Chlorocebus aethiops , Humanos , Italia , Pruebas de Neutralización , Pandemias , Reino Unido , Células Vero
14.
Viruses ; 13(2)2021 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-33671997

RESUMEN

Porcine epidemic diarrhea virus (PEDV) is a coronavirus that causes serious and highly contagious enteric disease in swine worldwide. In this study, we constructed a recombinant baculovirus (S-Bac) expressing full-length spike protein of the virulent epidemic genotype 2b (G2b) PEDV strain for serological studies of infected pigs. We found that most spike-specific antibodies produced upon PEDV infection in pigs are conformation-specific and they could be detected on S-Bac-infected insect cells by immunofluorescent assay, but they were insensitive to Western blot analysis, the typical method for antiserum analysis. These results indicated that spike conformation is crucial for serum recognition. Since it is difficult to purify trimeric spike membrane protein for conventional enzyme-linked immunosorbent assay (ELISA), we used S-Bac to generate a novel cell-based ELISA for convenient PEDV detection. We analyzed 100 pig serum samples, and our cell-based ELISA exhibited a sensitivity of 100%, a specificity of 97%, and almost perfect agreement [Cohen's kappa coefficient value (κ) = 0.98] with immunocytochemical staining results. Our cell-based ELISA rapidly presented antigen for proper detection of conformation-specific antibodies, making PEDV detection more convenient, and it will be useful for detecting many viral diseases in the future.


Asunto(s)
Anticuerpos Antivirales/sangre , Antígenos Virales/inmunología , Infecciones por Coronavirus/veterinaria , Ensayo de Inmunoadsorción Enzimática , Virus de la Diarrea Epidémica Porcina/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Animales , Baculoviridae/inmunología , Chlorocebus aethiops , Infecciones por Coronavirus/inmunología , Proteínas Recombinantes/inmunología , Spodoptera , Porcinos , Enfermedades de los Porcinos/inmunología , Enfermedades de los Porcinos/virología , Células Vero
15.
Viruses ; 13(2)2021 02 23.
Artículo en Inglés | MEDLINE | ID: mdl-33672213

RESUMEN

This study aimed to clarify whether infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is prevalent among the staff of a hospital providing treatment to patients with severe coronavirus disease 2019 (COVID-19) using radioligand assay (RLA). One thousand samples from the staff of a general hospital providing treatment to patients with severe COVID-19 were assayed for SARS-CoV-2 nucleocapsid protein (N) IgG using RLA. Nine patients with COVID-19 who had been treated in inpatient settings and had already recovered were used as control subjects, and 186 blood donor samples obtained more than 10 years ago were used as negative controls. Four of the 1000 samples showed apparently positive results, and approximately 10 or more samples showed slightly high counts. Interestingly, a few among the blood donor samples also showed slightly high values. To validate the results, antibody examinations using ELISA and neutralizing antibody tests were performed on 21 samples, and chemiluminescence immunoassay (CLIA) was performed on 201 samples, both resulting in a very high correlation. One blood donor sample showed slightly positive results in both RLA and CLIA, suggesting a cross-reaction. This study showed that five months after the pandemic began in Japan, the staff of a general hospital with a tertiary emergency medical facility had an extremely low seroprevalence of the antibodies against SARS-CoV-2. Further investigation will be needed to determine whether the slightly high results were due to cross-reactions or a low titer of anti-SARS-CoV-2 antibodies. The quantitative RLA was considered sensitive enough to detect low titers of antibodies.


Asunto(s)
Anticuerpos Antivirales/sangre , Inmunoglobulina G/sangre , Personal de Hospital , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Neutralizantes/sangre , /inmunología , Femenino , Humanos , Japón , Masculino , Persona de Mediana Edad , Pandemias , Fosfoproteínas/inmunología , Prevalencia , Estudios Seroepidemiológicos , Adulto Joven
16.
Viruses ; 13(2)2021 02 12.
Artículo en Inglés | MEDLINE | ID: mdl-33673067

RESUMEN

Neutralizing antibodies are an important part of the humoral immune response to SARS-CoV-2. It is currently unclear to what extent such antibodies are produced after non-severe disease or asymptomatic infection. We studied a cluster of SARS-CoV-2 infections among a homogeneous population of 332 predominantly male Swiss soldiers and determined the neutralizing antibody response with a serum neutralization assay using a recombinant SARS-CoV-2-GFP. All patients with non-severe COVID-19 showed a swift humoral response within two weeks after the onset of symptoms, which remained stable for the duration of the study. One month after the outbreak, titers in COVID-19 convalescents did not differ from the titers of asymptomatically infected individuals. Furthermore, symptoms of COVID-19 did not correlate with neutralizing antibody titers. Therefore, we conclude that asymptomatic infection can induce the same humoral immunity as non-severe COVID-19 in young adults.


Asunto(s)
Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Infecciones Asintomáticas , Inmunidad Humoral , Adulto , Estudios de Cohortes , Humanos , Masculino , Personal Militar , Pruebas de Neutralización , Suiza/epidemiología , Adulto Joven
17.
J Korean Med Sci ; 36(9): e64, 2021 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-33686810

RESUMEN

BACKGROUND: In Korea, there were issues regarding the use of immunoassays for anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies to detect infection. So, we compared antibody results of eight kinds of commercial immunoassays using clinical remnant specimens. METHODS: We compared the results of several immunoassay kits tested on 40 serum samples from 15 confirmed patients and 86 remnant serum samples from clinical laboratory. Eight kinds of IVD kits-four enzyme-linked immunosorbent assay, two lateral flow rapid immunochromatographic assays, and two chemiluminescent immunoassays with one RUO kit were tested. RESULTS: Among 40 serum samples from 15 coronavirus disease 2019 (COVID-19) patients, 35 yielded at least one positive result for detecting antibodies in the combined assessment. There were inconsistent results in 12 (28%) samples by single immunoassay. Forty samples collected in 2019 before the first COVID-19 Korean case showed negative results except for one equivocal result. CONCLUSION: The discrepant results obtained with different immunoassay kits in this study show that serological assessment of SARS-CoV-2 by a single immunoassay requires caution not only in detecting infection but also in assessing immunologic status.


Asunto(s)
Anticuerpos Antivirales/sangre , Inmunoensayo/métodos , /inmunología , /virología , Hospitalización , Humanos , Inmunoglobulina G/sangre , Juego de Reactivos para Diagnóstico , /aislamiento & purificación
18.
Sci Rep ; 11(1): 5160, 2021 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-33664279

RESUMEN

The extent that antibodies to SARS-CoV-2 may protect against future virus-associated disease is unknown. We invited all employees (n = 15,300) at work at the Karolinska University Hospital, Stockholm, Sweden to participate in a study examining SARS-Cov-2 antibodies in relation to registered sick leave. For consenting 12,928 healthy hospital employees antibodies to SARS-CoV-2 could be determined and compared to participant sick leave records. Subjects with viral serum antibodies were not at excess risk for future sick leave (adjusted odds ratio (OR) controlling for age and sex: 0.85 [95% confidence interval (CI) (0.85 (0.43-1.68)]. By contrast, subjects with antibodies had an excess risk for sick leave in the weeks prior to testing [adjusted OR in multivariate analysis: 3.34 (2.98-3.74)]. Thus, presence of viral antibodies marks past disease and protection against excess risk of future disease. Knowledge of whether exposed subjects have had disease in the past or are at risk for future disease is essential for planning of control measures.Trial registration: First registered on 02/06/20, ClinicalTrials.gov NCT04411576.


Asunto(s)
Anticuerpos Antivirales/sangre , /inmunología , Ausencia por Enfermedad/estadística & datos numéricos , Adulto , Anticuerpos Antivirales/inmunología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Suecia/epidemiología
19.
BMJ ; 372: n423, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33653694

RESUMEN

OBJECTIVE: To evaluate the performance of new lateral flow immunoassays (LFIAs) suitable for use in a national coronavirus disease 2019 (covid-19) seroprevalence programme (real time assessment of community transmission 2-React 2). DESIGN: Diagnostic accuracy study. SETTING: Laboratory analyses were performed in the United Kingdom at Imperial College, London and university facilities in London. Research clinics for finger prick sampling were run in two affiliated NHS trusts. PARTICIPANTS: Sensitivity analyses were performed on sera stored from 320 previous participants in the React 2 programme with confirmed previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Specificity analyses were performed on 1000 prepandemic serum samples. 100 new participants with confirmed previous SARS-CoV-2 infection attended study clinics for finger prick testing. INTERVENTIONS: Laboratory sensitivity and specificity analyses were performed for seven LFIAs on a minimum of 200 serum samples from participants with confirmed SARS-CoV-2 infection and 500 prepandemic serum samples, respectively. Three LFIAs were found to have a laboratory sensitivity superior to the finger prick sensitivity of the LFIA currently used in React 2 seroprevalence studies (84%). These LFIAs were then further evaluated through finger prick testing on participants with confirmed previous SARS-CoV-2 infection: two LFIAs (Surescreen, Panbio) were evaluated in clinics in June-July 2020 and the third LFIA (AbC-19) in September 2020. A spike protein enzyme linked immunoassay and hybrid double antigen binding assay were used as laboratory reference standards. MAIN OUTCOME MEASURES: The accuracy of LFIAs in detecting immunoglobulin G (IgG) antibodies to SARS-CoV-2 compared with two reference standards. RESULTS: The sensitivity and specificity of seven new LFIAs that were analysed using sera varied from 69% to 100%, and from 98.6% to 100%, respectively (compared with the two reference standards). Sensitivity on finger prick testing was 77% (95% confidence interval 61.4% to 88.2%) for Panbio, 86% (72.7% to 94.8%) for Surescreen, and 69% (53.8% to 81.3%) for AbC-19 compared with the reference standards. Sensitivity for sera from matched clinical samples performed on AbC-19 was significantly higher with serum than finger prick at 92% (80.0% to 97.7%, P=0.01). Antibody titres varied considerably among cohorts. The numbers of positive samples identified by finger prick in the lowest antibody titre quarter varied among LFIAs. CONCLUSIONS: One new LFIA was identified with clinical performance suitable for potential inclusion in seroprevalence studies. However, none of the LFIAs tested had clearly superior performance to the LFIA currently used in React 2 seroprevalence surveys, and none showed sufficient sensitivity and specificity to be considered for routine clinical use.


Asunto(s)
/diagnóstico , Inmunoensayo , /aislamiento & purificación , Adulto , Anticuerpos Antivirales/sangre , /epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Estudios Seroepidemiológicos , Reino Unido
20.
J Immunol Res ; 2021: 6680337, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33644235

RESUMEN

COVID-19 is a pandemic caused by SARS-CoV-2. In Chile, half a million people have been infected and more than 16,000 have died from COVID-19. As part of the clinical trial NCT04384588, we quantified IgG against S1-RBD of SARS-CoV-2 (anti-RBD) in recovered people in Santiago and evaluated their suitability as COVID-19 convalescent plasma donors. ELISA and a luminescent SARS-CoV-2 pseudotype were used for IgG and neutralizing antibody quantification. 72.9% of the convalescent population (468 of 639) showed seroconversion (5-55 µg/mL anti-RBD IgG) and were suitable candidates for plasma donation. Analysis by gender, age, and days after symptom offset did not show significant differences. Neutralizing activity correlated with an increased concentration of anti-RBD IgG (p < 0.0001) and showed a high variability between donors. We confirmed that the majority of the Chilean patients have developed anti-SARS-CoV-2 antibodies. The quantification of anti-RBD IgG in convalescent plasma donors is necessary to increase the detection of neutralizing antibodies.


Asunto(s)
/inmunología , /fisiología , Glicoproteína de la Espiga del Coronavirus/inmunología , Adolescente , Adulto , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/uso terapéutico , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/uso terapéutico , Chile , Femenino , Humanos , Inmunización Pasiva/métodos , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Pandemias , Seroconversión , Adulto Joven
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