Antiphospholipid antibody (aPL) presence in COVID-19 patients

Objective: In our study, we aimed to show whether there is a relationship between antiphospholipid antibody (aPL) positivity and complications of COVID-19. Material and Methods: Eighty-three patients who were diagnosed with COVID-19 infection and hospitalized in the intensive care unit (ICU) of Bakirkoy Dr. Sadi Konuk Research and Training Hospital were included in our study as the case group and 79 healthy volunteers as the control group. Only patients with a positive Polymerase Chain Reaction (PCR) test were included in the case group. Serum antiphospholipid antibodies (aPL IgM/G), C-Reactive Protein (CRP), ferritin, procalcitonin (PCT), plasma D-Dimer levels, prothrombin time (PT), international normalized ratio (INR), and activated partial thromboplastin time (aPTT) were analyzed by routine laboratory methods. Results: Both groups were found statistically similar in terms of gender (X2 test, p=0.236). The mean age of the case group and control group was 60.54..16.86 and 51.47..14.64 years, respectively. When aPL positivity was evaluated between the case and control groups, a statistically remarkable difference was found between the groups (p=0.046). The case group showed an aPL positivity of 7.5% and the control group 1%. The correlation between D-Dimer, PT, INR, aPTT levels, and aPL IgM/G positivity in the case group was significant. Conclusion: Our results revealed that aPL positivity in patients with COVID-19 infection relate to the severity of the disease, independent from age and gender. To confirm the result of this study further studies with participation of larger patient groups from national and international hospitals are required.

Transmission of SARS-CoV-2 associated with wastewater treatment: a seroprevalence study

The detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during wastewater treatment leads to concerns about whether this process may represent a focal point for the transmission of COVID-19. An epidemiological analysis, based on a COVID-19 IgG/IgM Rapid Test Cassette, performed on 134 wastewater workers from 59 wastewater treatment plants from the province of Granada (Spain) showed a seroprevalence of 8.95% in IgG for SARS-CoV-2, which is similar to the incidence rate found for the general population of the province (9.6%;95%CI = 7.2-12.8). These findings suggest that current safety measures are sufficient for the protection of workers against SARS-CoV-2.

Dynamic characteristics of specific antibodies IgM, IgG and viral RNA in patients with COVID-19

Objective: To study the changed trend of IgM and IgG specific antibody with chemiluminescent immunoassay (CLIA) and RT-PCR in SARS-CoV-2 infection patients during hospitalization. Methods: A total of 100 hospitalized patients with SARS-CoV-2 infection who admitted to the First People's Hospital of Zhaoqing were divided into vaccinated group and unvaccinated group according to whether they were vaccinated COVID-19 vaccine or not. The unvaccinated group was further divided into severe, normal, mild and asymptomatic groups. The nucleic acid test results, the positive rate of IgM and IgG antibodies measured by CLIA, and the dynamic trend of S/CO values of all SARS-CoV-2 infected patients since admission 0-<8 days, 8-<15 days, 15-<22 days, 22-<29 days, 29-<36 days and36 days were monitored, and the statistical differences between different groups were compared. Results: The positive rate of IgM antibody in the unvaccinated group 55.6% (15/27) and 0 (0/27) were all significantly higher than that in the vaccinated group 68.5% (50/73) and 49.0% (36/73) at 8-<15 days and 36 days of hospitalization (X2=11.048, 20.805, P < 0.05). The positive rate of IgG antibody in the vaccinated group 96.3% (26/27) and 100% (27/27) were all significantly higher than that in the unvaccinated group 45.2% (31/73) and 78.1% (57/73) at 0-< 8 days and 8-<15 days of hospitalization (X2=21.268, 7.576, P < 0.05). The positive rate of RNA in the unvaccinated were all significantly higher than that in the vaccinated group at 8-<15 days 76.7% (56/73) and 29.6% (8/27), 15-<22 days 65.8% (48/73) and 14.8% (4/27), 22-<29 days 42.5%(31/73) and 7.4% (2/27), 29~<36 days 26.0% (19/73) and 7.4% (2/27) of hospitalization (X2=18.694,20.490, 10.957, 4.119, all P < 0.05). The S/CO value of IgG antibody in the vaccinated group were all significantly higher than that in the unvaccinated group at differentperiods of hospitalization (t=2.841, 7.135, all P < 0.05), but there was no significant difference in the S/CO value of IgM antibodyat different periods of hospitalization in pairwise comparison (P > 0.05). The IgM and IgG antibody levels of severe patients in the unvaccinated group were significantly higher than those in the normal, mild, and asymptomatic groups at 22-<29 days and 29-<36 days of hospitalization (F=17.694,15.116, 4.037, 4.115, all P < 0.05). Conclusion: IgM and IgG antibody levels in severe patients are more activated by immune defense during recovery. In the case of vaccination, IgM antibody can well reflect the whole course of SARS-CoV-2 infection.

Epidemiological study and health management of an imported incident of COVID-19 asymptomatic cases in Haikou, China: a retrospective case series

Background: To control the imported risks brought by all international arrivals, China Customs has implemented strict closed-loop health management policy called "three checks, three screenings and one transfer". This study provides epidemiological evidence for prevention and control measures on imported cases of asymptomatic infections and describes the current COVID-19 prevention and control system on imported risks in China. Methods: We retrospectively analyzed an imported incident of three asymptomatic carriers. Serum SARS-CoV-2 IgM and IgG antibodies were detected by chemiluminescence and gold immnnochromatography(GICA). Results: Three cases were reported positive for SARS-CoV-2 nucleic acid on their arrival, total antibodies and IgG, but negative for IgM. The Ct values of cases A, B and C were 34/36/36, 32/33/32 and 25/31/29, respectively. There were 10726434 pair-end reads sequenced for case C, and approximate 80% reads were aligned to the hCoV-19/Wuhan/IVDC-HB-01/2019 genome (EPI_ISL_402119). The viruses of case A and C were homologous and came from the SARS-CoV-2 variant. Conclusion: Serum antibody IgM and IgG tests are recommended for international travelers from epidemic areas. The "three checks, three screenings and one transfer" policy implemented at custom's entry points was effective in COVID-19 prevention and control.

Comparison of clinical manifestations, liver function, and antibody levels between omicron variant infection patients vaccinated and not vaccinated with COVID-19 vaccine

Objective: To compare the clinical manifestations, liver function, and antibody levels between Omicron variant infection patients vaccinated and not vaccinated with COVID-19 vaccine. Methods: Totally 430 convalescent COVID-19 patients infected with Omicron variant in Tianjin were selected, including 150 patients vaccinated with Corona Vaccine(Sinovac group), 185 patients vaccinated with BBIBP-CorV(Beijing biological group), 41 patients vaccinated with Ad5-nCoV vaccine(CanSino group), 16 patients vaccinated with Anhui Zhifei, Changchun Bio, Lanzhou Bio, Shandong Bio, other adenovirus vector vaccines or mixed vaccination(other group), and 38 unvaccinated patients(unvaccinated group). The clinical manifestations, liver function indexes [alanine aminotransferase(ALT), aspartate aminotransferase(AST), total bilirubin(TB), albumin(ALB), total protein(TP), lactate dehydrogenase(LDH)], and antibody levels(IgG, IgM)were compared retrospectively. Results: There was no statistical difference in the sex composition ratio among groups(P > 0.05). The age of the Beijing biological group was significantly lower than that of other groups, and the proportion of time less than 3 months from the last vaccination to admission in the Beijing biological group and CanSino group was significantly higher than that in the Sinovac group and other groups(all P < 0.01). A total of 110 children aged less than 16 years were enrolled, including 7, 88, 0, 1 and 14 cases in the Sinovac group, Beijing biological group, CanSino group, other group, and unvaccinated group, respectively. There were 6 asymptomatic cases, 13 moderate cases, 91 mild cases and 0 severe case. There was no significant difference in the abnormal rate of ALT between Beijing biological group and unvaccinated group(P > 0.05), but the abnormal rates of ALT were higher in the Sinovac group and CanSino group than in the unvaccinated group and Beijing biological group(all P < 0.05). The abnormal rate of AST in the unvaccinated group was higher than that in other groups(P < 0.05). There were no significant differences in AST, TP or TB among the groups(all P > 0.05). The levels of ALT were higher in the Sinovac group and CanSino group than in Beijing biological Group and unvaccinated group, the level of ALB in the unvaccinated group was lower than that in the other groups, and the level of LDH in the Beijing biological group was higher than those in the Sinovac group and CanSino group(both P < 0.05). The IgG and IgM antibody levels of the unvaccinated group were significantly lower than those of the Sinovac group, Beijing biological group and CanSino group(all P < 0.05). Conclusions: Omicron variant infection patients vaccinated with BBIBP-CorV are younger and have a higher proportion of mild conditions, which can protect the liver function of patients to a certain extent. Patients vaccinated with different COVID-19 vaccines can produce higher levels of IgG and IgM antibodies than the unvaccinated patients.

Impact of vitamin D3 supplementation on COVID-19 vaccine response and immunoglobulin G antibodies in deficient women: A randomized controlled trial.

BACKGROUND: Immune levels were observed by giving vitamin D supplements to vitamin D deficient women who received the COVID-19 vaccine. METHODS: In the research, there were volunteer women who had received two doses of the COVID-19 vaccine who participated for a mean of more than 65 days. Group D (n=14 Pfizer-BioNTech, 2 Sinovac) received 150,000 IU of vitamin D supplementation, but group C (n=14 Pfizer-BioNTech), 3 Sinovac) no support was provided. RESULTS: When the consumption of vitamin D ends (D group), serum 25-Hydroxy Vitamin D levels were found to increase regularly in the (W3) last measurements (p=0.001). There was no significant difference in immunoglobulin M levels between groups D and C (Control group) (p=0.063). It was observed that the immunoglobulin G levels reached the peak level between the W1 and W2 measurements of the D group (P<0.001) and there were significant differences between the three sizes. Also, no correlation was found between the D group's initial serum immunoglobulin G and 25-Hydroxy Vitamin D levels. However, when the final measurements were examined, a significant positive correlation was found between immunoglobulin G and 25-Hydroxy Vitamin D levels (r=0.558, p=0.031). CONCLUSION: It was determined that serum IgG levels increased significantly depending on the duration between those who used vitamin D and those who did not and it was above the initial level for a long time. A positive and significant relationship was found between the last measured immunoglobulin G and 25(OH) D levels while vitamin D supplementation continued. TRIAL REGISTRATION: This study registered under ClinicalTrials.gov (Identifier no. NCT05447065).

The SARS-COV-2 Seroprevalence among Oncology Patients.

Patients with cancer are presumed to be vulnerable to an increased risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe clinical outcomes due to the immunocompromised state mediated by their underlying malignancies and therapy. The aim of this study was to estimate the SARS-CoV-2 seroprevalence, following second to fourth waves in solid tumour patients attending the Steve Biko Academic Hospital (SBAH) for diagnosis and treatment of cancer. We used the single-prick COVID-19 IgG/IgM Rapid Test Cassettes to detect SARS-CoV-2 IgG/IgM antibodies in 760 patients with solid tumours who were asymptomatic and who had never tested positive for coronavirus disease 2019 (COVID-19). Out of the 760 patients, 277 were male (36.4%), 483 were female (63.6%), and the mean age was 55 years (range 18−92). The estimated total seroprevalence was 33.2%. The seroprevalence status of the COVID-19 IgG/IgM antibodies rose significantly from the second wave (11.3%) to the third (67.38%) and then the fourth (69.81%) waves with roughly similar counts. A significant number of the seropositive patients were asymptomatic to COVID-19 (96%). There was a higher rate of seropositivity in cancer patients with hypertension (p < 0.05). Patients with breast, gynaecologic, and prostate cancers exhibited increased SARS-CoV-2 seropositivity. Although oncology patients may be susceptible to SARS-CoV-2 infection, our data indicate that these patients remained asymptomatic throughout various waves with an overall COVID-19 IgG/IgM antibody seropositivity of 33.16%, suggesting no risk of severe or fatal cases of COVID-19.

Performance of the FREND™ COVID-19 IgG/IgM Duo point-of-care test for SARS-CoV-2 antibody detection.

PURPOSE: In the context of the current COVID-19 pandemic, multiple serological assays for the detection of severe acute respiratory syndrome 2 (SARS-CoV-2) immune response are currently being developed. This study compares the FRENDTM COVID-19 IgG/IgM Duo (NanoEntec) a point of care (POCT) assay with the automated Elecsys anti-SARS-CoV-2 electrochemiluminescent assay (Roche Diagnostics). METHODS: Serum samples (n = 81) from PCR-confirmed SARS-CoV-2 positive patients at different time points after the onset of symptoms were analyzed with both assays. An additional 24 serum samples with cross reactivity potential were also included. RESULTS: The sensitivity of the COVID-19 IgG/IgM Duo assay was higher as compared to the Elecsys anti-SARS-CoV-2 assay, especially when using the combined IgM/IgG result in samples analyzed within 6 days after the onset of symptoms (46.2% vs. 15.4%). The sensitivity of both assays increased with increasing time interval after the onset of symptoms and reached 100% for the COVID-19 IgG/IgM Duo assay in samples taken 14 days or more after symptom onset. Specificity of the COVID-19 IgG/IgM Duo assay was 95.8% for IgM, 91.7% for IgG and 87.5% for the combination of both. CONCLUSION: This study shows that the sensitivity of both assays was highly dependent on the time interval between the onset of the COVID-19 symptoms and serum sampling. Furthermore, rapid serological testing for SARS-CoV-2 antibodies by means of the FRENDTM COVID-19 IgG/IgM Duo POCT assay showed a comparable diagnostic performance as the reference automated immunoassay.

Ultrasensitive monitoring of SARS-CoV-2-specific antibody responses based on a digital approach reveals one week of IgG seroconversion.

COVID-19 is still unfolding, while many people have been vaccinated. In comparison to nucleic acid testing (NAT), antibody-based immunoassays are faster and more convenient. However, its application has been hampered by its lower sensitivity and the existing fact that by traditional immunoassays, the measurable seroconversion time of pathogen-specific antibodies, such as IgM or IgG, lags far behind that of nucleic acids. Herein, by combining the single molecule array platform (Simoa), RBD, and a previously identified SARS-CoV-2 S2 protein derivatized 12-aa peptide (S2-78), we developed and optimized an ultrasensitive assay (UIM-COVID-19 assay). Sera collected from three sources were tested, i.e., convalescents, inactivated virus vaccine-immunized donors and wild-type authentic SARS-CoV-2-infected rhesus monkeys. The sensitivities of UIM-COVID-19 assays are 100-10,000 times higher than those of conventional flow cytometry, which is a relatively sensitive detection method at present. For the established UIM-COVID-19 assay using RBD as a probe, the IgG and IgM seroconversion times after vaccination were 7.5 and 8.6 days vs. 21.4 and 24 days for the flow cytometry assay, respectively. In addition, using S2-78 as a probe, the UIM-COVID-19 assay could differentiate COVID-19 patients (convalescents) from healthy people and patients with other diseases, with AUCs ranging from 0.85-0.95. In summary, the UIM-COVID-19 we developed here is a promising ultrasensitive biodetection strategy that has the potential to be applied for both immunological studies and diagnostics.

Risk of vertical transmission of SARS CoV-2 infection to neonates born to covid positive mothers: A pilot study from a tertiary care hospital of North India.

OBJECTIVES: To assess the risk of neonatal SARS-CoV-2 infection born to the women with confirmed SARS-CoV-2 infection. MATERIALS AND METHODS: This prospective study was conducted at single tertiary hospital from September 2020 and May 2021. 50 pregnant women with confirmed SARS-CoV-2 infection and 50 neonates were included for analysis. We performed comprehensive testing of all biological samples for vertical transmission including the cord blood immunoglobulin. RESULTS: We detected SARS-CoV-2 in one fetal membrane and one amniotic fluid sample. We also demonstrated presence of anti-SARS-CoV-2 IgM antibodies in cord blood of 3 neonates. Though none of the samples of vaginal secretion, breast milk and nasopharyngeal swab from neonates were tested positive for covid infection via RT-PCR. We demonstrated presence of anti-SARS-CoV-2 IgG antibodies in the cord blood which had shown positive correlation with increasing disease to delivery interval and disease severity. CONCLUSION: Vertical transmission of SARS-CoV-2 is possible. As virus was not detected in cervicovaginal secretions and breast milk so vertical transmission through this mechanism seems unlikely. Presence of IgG in cord blood is suggestive of passive immunity acquired from mother. This finding has greater clinical implication as large number of expecting mothers are being vaccinated.

Performance evaluation of four rapid antibody tests for the detection of severe acute respiratory syndrome coronavirus 2.

BACKGROUND: The prompt detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important in the therapeutic management of infected patients. Rapid diagnostic tests are widely used for this purpose. This study aimed to evaluate the clinical performance of four SARS-CoV-2 immunoglobulin IgG/IgM rapid diagnostic tests in the detection of SARS-CoV-2. METHODS: Nasopharyngeal and oropharyngeal swabs and/or sputum were collected from 30 patients infected with SARS-CoV-2 and 30 healthy volunteers. All specimens were tested using four SARS-CoV-2 IgG/IgM rapid diagnostic tests and real-time polymerase chain reaction. We assessed the clinical sensitivity and specificity of the tests. RESULTS: The clinical sensitivity of FREND™, SsmarTest™, BIOCREDIT™, and IVDLAB™ was 96.67%, 100.00%, 100.00%, and 96.67%, respectively, compared to real-time polymerase chain reaction. The clinical specificity was 96.67%, 100.00%, 86.67%, and 96.67%, respectively. CONCLUSION: These findings could expedite the detection of SARS-CoV-2 and thus reduce the risk of further transmission of the virus.

Rapid Quantitative Point-Of-Care Diagnostic Test for Post COVID-19 Vaccination Antibody Monitoring.

Point-of-care (POC) quantification of antibody responses against SARS-CoV-2 spike protein can enable decentralized monitoring of immune responses after infection or vaccination. We evaluated a novel POC microfluidic cartridge-based device (ViroTrack Sero COVID-19 Total Ab) for quantitative detection of total antibodies against SARS-CoV-2 spike trimeric spike protein compared to standard laboratory chemiluminescence (CLIA)-based tests. Antibody responses of 101 individuals were measured on capillary blood, venous whole blood, plasma, and diluted plasma samples directly on the POC. Results were available within 7 min. As the reference, plasma samples were analyzed on DiaSorin LIAISON XL CLIA analyzer using LIAISON SARS-CoV-2 IgM, LIAISON SARS-CoV-2 S1/S2 IgG, and LIAISON SARS-CoV-2 TrimericS IgG assays. The Spearman rank's correlation coefficient between ViroTrack Sero COVID-19 Total Ab and LIAISON SARS-CoV-2 S1/S2 IgG and LIAISON SARS-CoV-2 TrimericS IgG assays was found to be 0.83 and 0.89, respectively. ViroTrack Sero COVID-19 Total Ab showed high correlation between the different matrixes. Agreement for determination of samples of >230 binding antibody units (BAU)/mL on POC and CLIA methods is estimated to be around 90%. ViroTrack Sero Covid Total Ab is a rapid and simple-to-use POC test with high sensitivity and correlation of numerical results expressed in BAU/mL compared to those of a commercial CLIA assay. IMPORTANCE Serological testing is an important diagnostic support tool in the fight against COVID-19. So far, serological testing has been performed on either lateral flow assays, which perform only qualitatively and can be difficult for the individual to read, or standard laboratory assays, which are time- and resource-consuming. The purpose of the study was to evaluate the performance of a new POC microfluidic cartridge-based device based on immunomagnetic agglutination assay that can provide an accurate numerical quantification of the total antibodies within only 7 min from a single drop of capillary blood. We demonstrated a high level of correlation between the POC and the two CLIA laboratory-based immunoassays from Diasorin, thus allowing a potentially wider use of quantitative serology tests in the COVID-19 pandemic.

INDICATORS OF ANTIBODIES IgM AND IgG TO SARS-COV-2 IN RESIDENTS OF YAKUTSK AFTER RECOVERY FROM COVID-19

A study of IgM and IgG antibodies to SARS-COV-2 was carried out in 161 residents of Yakutsk at the age from 20 to 72 years old who had a new coronavirus infection COVID-19 from 3, 6, 9 and 12 months ago. The aim of the work was to assess the content of serum immunoglobulins IgM and IgG to SARS-COV-2 in persons who have had COVID-19, depending on the duration and severity of the disease. The intensity of the immune response was assessed using the coefficient of positivity (CP) as the ratio of the optical density of the sample to the critical value of the optical density. According to the results of the study, the seroprevalence in all 4 groups of patients with Covid-19 was 100%. Antibodies IgG and IgM to SARS-CoV-2 in those who had been ill with COVID-19 persisted up to 12 months and depended on the postcovid period, age and severity of lung lesions on CT.

Persistence of SARS-CoV-2-Specific Antibodies for 13 Months after Infection.

BACKGROUND: Dynamics of antibody responses were investigated after a SARS-CoV-2 outbreak in a private company during the first wave of the pandemic. METHODS: Workers of a sewing company (Lithuania) with known SARS-CoV-2 RT-PCR result during the outbreak (April 2020) were invited to participate in the study. Virus-specific IgG and IgM were monitored 2, 6 and 13 months after the outbreak via rapid IgG/IgM serological test and SARS-CoV-2 S protein-specific IgG ELISA. RESULTS: Six months after the outbreak, 95% (CI 86-99%) of 59 previously infected individuals had virus-specific antibodies irrespective of the severity of infection. One-third of seropositive individuals had virus-specific IgM along with IgG indicating that IgM may persist for 6 months. Serological testing 13 months after the outbreak included 47 recovered individuals that remained non-vaccinated despite a wide accessibility of COVID-19 vaccines. The seropositivity rate was 83% (CI 69-91%) excluding one case of confirmed asymptomatic reinfection in this group. Between months 6 and 13, IgG levels either declined or remained stable in 31 individual and increased in 7 individuals possibly indicating an exposure to SARS-CoV-2 during the second wave of the pandemic. CONCLUSIONS: Detectable levels of SARS-CoV-2-specific antibodies persist up to 13 months after infection for the majority of the cases.

Multicentric evaluation of a novel point of care electrochemical ELISA platform for SARS-CoV-2 specific IgG and IgM antibody assay.

New diagnostics technologies for the efficient detection and quantification of SARS-CoV-2 antibodies are very crucial to manage the COVID-19 pandemic, especially in the context of emerging vaccination paradigms. Herein, we report on a novel point-of-care Electrochemical ELISA platform with disposable screen printed electrodes functionalized with SARS-CoV-2 Spike Glycoprotein S1, to enable fast and accurate quantitative estimation of total antibody concentration (IgG and IgM) in clinical samples. The quantification is performed with a comparison of electrochemical redox current against the current produced by the spiked monoclonal antibodies with known concentration. The assay is validated through multicentric evaluation against 3 different FDA authorized Laboratory standard techniques, using both EDTA whole blood and serum samples. We demonstrate that the proposed assay has excellent sensitivity and specificity, making it a suitable candidate for epidemiological surveys and quantification of antibodies in COVID-19 vaccination programs.

Dynamic changes and prevalence of SARS-CoV-2 IgG/IgM antibodies: Analysis of multiple factors.

OBJECTIVE: To investigate the dynamic characteristics of serological antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is of much current significance. METHODS: The dynamic changes and prevalence of immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against SARS-CoV-2 were assessed from the time of symptom onset up to 210 days. Antibodies were detected using a chemiluminescence immunoassay. RESULTS: The average titers and IgG/IgM positivity rates reached a peak within 30 days of symptom onset and then began to decline continuously. Between 180 and 210 days following symptom onset, the titers of IgG and IgM were 43.1 ± 27.0 AU/mL and 4.4 ± 5.2 AU/mL, respectively, while the respective positivity rates were 84.3% and 12.0%. Further statistical analyses revealed that the dynamic changes and prevalence of the SARS-CoV-2 IgG/IgM antibodies were related to age and disease severity, but not to sex. The dynamic changes and the prevalence were similar for both the IgM and the IgG antibodies. Even so, there was a more rapid rate of decline for the IgM antibodies. It was found that an IgG level of 16.33 ± 3.15 AU/mL may represent a threshold value that should act as an alert, as it may indicate that the IgG level will become undetectable within the next 30-60 days. CONCLUSION: The results provide important information concerning COVID-19 and may be of relevance for diagnosis, treatment, and vaccine development.

Ultrasensitive, high-throughput, and rapid simultaneous detection of SARS-CoV-2 antigens and IgG/IgM antibodies within 10 min through an immunoassay biochip.

COVID-19 is now a severe threat to global health. Facing this pandemic, we developed a space-encoding microfluidic biochip for high-throughput, rapid, sensitive, simultaneous quantitative detection of SARS-CoV-2 antigen proteins and IgG/IgM antibodies in serum. The proposed immunoassay biochip integrates the advantages of graphene oxide quantum dots (GOQDs) and microfluidic chip and is capable of conducting multiple SARS-CoV-2 antigens or IgG/IgM antibodies of 60 serum samples simultaneously with only 2 µL sample volume of each patient. Fluorescence intensity of antigens and IgG antibody detection at emission wavelength of ~680 nm was used to quantify the target concentration at excitation wavelength of 632 nm, and emission wavelength of ~519 nm was used during the detection of IgM antibodies at excitation wavelength of 488 nm. The method developed has a large linear quantification detection regime of 5 orders of magnitude, an ultralow detection limit of ~0.3 pg/mL under optimized conditions, and less than 10-min qualitative detection time. The proposed biosensing platform will not only greatly facilitate the rapid diagnosis of COVID-19 patients, but also provide a valuable screening approach for infected patients, medical therapy, and vaccine recipients.

Side effects and antibody titer transition of the BNT162b2 messenger ribonucleic acid coronavirus disease 2019 vaccine in Japan.

BACKGROUND: The coronavirus disease (COVID-19) has afflicted large populations worldwide. Although vaccines aroused great expectations, their side effects on Japanese people and the antibody titer transition after vaccination are unclear. METHODS: The side effects of the BNT162b2 mRNA COVID-19 vaccine in participants who received vaccination at our center were investigated. Some participants were also surveyed for the antibody titer transition. RESULTS: In this study, 983 and 798 Japanese participants responded to the first and second doses, respectively. Side effects occurred in 757 (77.0%) and 715 participants (90.0%) after the first and second doses, respectively. No Grade 4 side effects occurred. The second dose had significantly more side effects than the first dose (p < 0.001). Side effects occurred after the second dose in 571 female (92.1%) and 178 male participants (80.1%). Female participants had a higher incidence of side effects than the male participants (p < 0.001). A comparison among the age groups showed significant differences (p = 0.018), and the frequency of side effects decreased with age. Twenty-three individuals participated in the survey of antibody titer transition. After the second vaccine dose, the median antibody titers for IgG and IgM were 3.76 and 0.07 AU/mL, respectively. Both IgG and IgM titers showed a significant increase over the study period (p < 0.001). CONCLUSIONS: The BNT162b2 mRNA COVID-19 vaccine might be safe for Japanese people, and the antibody titer increased with two doses of vaccination. Larger nationwide studies are warranted to verify these findings.

Evaluation of commercially available immuno-magnetic agglutination in comparison to enzyme-linked immunosorbent assays for rapid point-of-care diagnostics of COVID-19.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is caused by Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Fast, accurate, and simple blood-based assays for quantification of anti-SARS-CoV-2 antibodies are urgently needed to identify infected individuals and keep track of the spread of disease. METHODS: The study included 33 plasma samples from 20 individuals with confirmed COVID-19 by real-time reverse-transcriptase polymerase chain reaction and 40 non-COVID-19 plasma samples. Anti-SARS-CoV-2 immunoglobulin M (IgM)/immunoglobulin A (IgA) or immunoglobulin G (IgG) antibodies were detected by a microfluidic quantitative immunomagnetic assay (IMA) (ViroTrack Sero COVID IgM + IgA/IgG Ab, Blusense Diagnostics) and compared to an enzyme-linked immunosorbent assay (ELISA) (EuroImmun Medizinische Labordiagnostika). RESULTS: Of the 33 plasma samples from the COVID-19 patients, 28 were positive for IgA/IgM or IgG by IMA and 29 samples were positive by ELISA. Sensitivity for only one sample per patient was 68% for IgA + IgM and 75% IgG by IMA and 80% by ELISA. For samples collected 14 days after symptom onset, the sensitivity of both IMA and ELISA was around 91%. The specificity of the IMA reached 100% compared to 95% for ELISA IgA and 97.5% for ELISA IgG. CONCLUSION: IMA for COVID-19 is a rapid simple-to-use point-of-care test with sensitivity and specificity similar to a commercial ELISA.