Evaluation of the Roche SARS-CoV-2 Rapid Antibody Test in samples from vaccinated individuals

Objective The study aimed to establish the performance of the SARS-CoV-2 Rapid Antibody Test (IgG and IgM) and the Elecsys® Anti-SARS-CoV-2 S assay in vaccinated individuals. Methods A panel of serum samples from Boca Biolistics was utilized to assess antibodies following vaccination, consisting of samples drawn prior to vaccination, after the first dose, or at least 14 days after the second dose of Moderna mRNA-1273 or Pfizer-BioNTech BNT162b2 COVID-19 vaccines. Agreement between the two methods was measured and stratified by test evaluator and assay lot. Results Agreement between the SARS-CoV-2 Rapid Antibody Test (IgG) and Elecsys Anti-SARS-CoV-2 S assay qualitative measurements at the different assessment points for both mRNA-1273 and BNT162b2 ranged between 97.06% (95% confidence interval [CI] 84.67, 99.93) to 100% (95% CI 82.35, 100). Agreement of the SARS-CoV-2 Rapid Antibody Test (IgG) with the Elecsys Anti-SARS-CoV-2 S assay was not highly influenced by either lot or evaluator. There was a medium-to-strong correlation between the semi-quantitative SARS-CoV-2 Rapid Antibody Test (IgG) result and quantitative Elecsys Anti-SARS-CoV-2 S assay in samples taken after both doses of the vaccines, with higher intensity bands being associated with higher total anti-S antibody titer (mRNA-1273, p=0.0019; BNT162b2, p<0.0001). Conclusion Semi-quantitative SARS-CoV-2 Rapid Antibody Test (IgG) and quantitative Elecsys Anti-SARS-CoV-2 S assay correlated well, suggesting that the SARS-CoV-2 Rapid Antibody Test (IgG) is helpful in understanding the immune response post-vaccination. The current data support the use of the SARS-CoV-2 Rapid Antibody Test (IgG) in the vaccinated population.

Evaluation of sensitivity and spesitivity as COVID–19 screening method

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Antibody rapid test is one of the COVID-19 screening tests that can be used in the community. The accuracy of the rapid antibody methods needs to be appropriately assessed, it is necessary to carry out a diagnostic accuracy study using a pairwise sensitivity and specificity analysis. This research aimed to assess the sensitivity and specificity of COVID-19 rapid tests, also assesses positive predictive value (PPV) and negative predictive value (NPV) of the rapid antibody test as a method of screening for COVID-19 in Sleman Regency, Indonesia. In total, 118 respondents who have contact with COVID-19 patients and have symptoms were enrolled in this study. The study was conducted on 118 patients who had been in contact with confirmed COVID-19 118 patients who met the close contact criteria were conducted a rapid antibody test. 64.41% patients were reactive. Real-time polymerase chain reaction (RT PCR) as a gold standard was also carried out for all patients and 63.56% affirmed positive for COVID-19. The sensitivity value was 97.33%, and the specificity value was 93.02%, while the positive predictive value (NPP) was 96.05%, and the negative predictive value (NPN) was 95.24%. These results meet the minimum recommendations for the screening method.

Assessment of the Field Utility of a Rapid Point-of-Care Test for SARS-CoV-2 Antibodies in a Household Cohort

Point-of-care (POC) tests to detect SARS-CoV-2 antibodies offer quick assessment of serostatus after natural infection or vaccination. We compared the field performance of the BioMedomics COVID-19 IgM/IgG Rapid Antibody Test against an ELISA in 303 participants enrolled in a SARS-CoV-2 household cohort study. The rapid antibody test was easily implemented with consistent interpretation across 14 users in a variety of field settings. Compared with ELISA, detection of seroconversion lagged by 5 to 10 days. However, it retained a sensitivity of 90% (160/177, 95% confidence interval [CI] 85–94%) and specificity of 100% (43/43, 95% CI 92–100%) for those tested 3 to 5 weeks after symptom onset. Sensitivity was diminished among those with asymptomatic infection (74% [14/19], 95% CI 49–91%) and early in infection (45% [29/64], 95% CI 33–58%). When used appropriately, rapid antibody tests offer a convenient way to detect symptomatic infections during convalescence.

Validation of rapid antibody (IgG-IgM) test kit for SARS COV-2 infection in Qatar

Background: In response to the growing coronavirus disease 2019 (COVID-19) pandemic and the shortage of laboratory based molecular testing capacity and reagents, multiple diagnostic test manufacturers have developed rapid and easy to use devices to facilitate testing outside laboratory settings. These kits are either based on detection of proteins from SARS-CoV-2 virus or detection of antigen or human antibodies generated in response to the infection. However, it is important to understand their performance characteristics and they must be validated in the local population setting.Design and Methods: The objective is to assess the validity of the rapid test for IgG and IgM immunoglobulins compared to the current gold standard reverse transcription polymerase chain reaction (RT-PCR) test. A total of 16951 asymptomatic individuals were tested by the Ministry of Public Health track-and-trace team using both rapid immunodiagnostic test and RT-PCR as part of screening across various random settings with potential risk of community interaction prior to gradual lifting of restrictions in Qatar. Rapid test was considered to be posiive if both IgG and IgM are positive, while only IgG/IgM positive was considered as rapid test negative. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.Results: The sensitivity of rapid test kit was found to be 0.9%, whereas the specificity was found to be 97.8%. the PPV was found to be 0.3% whereas the NPV was found to be 99.4%.Conclusion: Based on the outcome and results of the study, it appears that the sensitivity and PPV of the rapid antibody test are low. As such, this test is not recommended for use to assist in taking clinic-based decisions or decisions related to quarantine/isolation.

mRNA Vaccines Induce Rapid Antibody Responses in Mice

mRNA vaccines can be developed and produced quickly, making them attractive for immediate outbreak responses. Furthermore, clinical trials have demonstrated rapid protection following mRNA vaccination. We sought to investigate how quickly mRNA vaccines elicit antibody responses compared to other vaccine modalities. We first examined immune kinetics of mRNA and DNA vaccines expressing SARS-CoV-2 spike in mice. We observed rapid induction of antigen-specific binding and neutralizing antibodies by day 5 following mRNA, but not DNA, immunization. The mRNA vaccine also induced increased levels of IL-5, IL-6 and MCP-1. We then evaluated immune kinetics of an HIV-1 mRNA vaccine in comparison to DNA, protein, and rhesus adenovirus 52 (RhAd52) vaccines with the same HIV-1 envelope antigen in mice. Induction of envelope-specific antibodies was observed by day 5 following mRNA vaccination, whereas antibodies were detected by day 7-14 following DNA, protein, and RhAd52 vaccination. Eliciting rapid humoral immunity may be an advantageous property of mRNA vaccines for controlling infectious disease outbreaks.

Active immunization by COVID-19 mRNA vaccine results in rapid antibody response and virus reduction in breakthrough infection by Delta (B.1.617.2)

Vaccination is expected to suppress COVID-19 infection. However, breakthrough infections have increased following vaccination because of the spread of variants of concern, notably Delta (B.1.617.2 lineage). Virological and serological data pertaining to post-vaccination infections are limited. Here, we conducted genome analysis determined the viral lineages that infected patients following vaccination. Changes in viral load, antibody levels, and viral antigen levels following infection were analyzed. At the time of infection, Delta-infected patients had a 6.2-fold and 12.3-fold higher viral load compared with Alpha and other lineages, respectively. Viral lineages (Delta:Alpha:Other) of infection were 0:12:0 in the fully vaccinated group, 1:11:0 in the partially vaccinated group, 9:16:0 in the shortly after vaccination group, and 254:229:165 in the unvaccinated group. Breakthrough infections occurred regardless of retention of high antibody titers following vaccination. At the time of diagnosis, Delta-infected patients showed high viral load with or without vaccination. However, no fully vaccinated patients developed severe disease, and the rapid increase in anti-spike antibodies occurred approximately 1 week after onset of symptoms. Concomitantly, a decrease in viral antigen levels was observed in fully vaccinated patients, shortening the time to negative result by approximately 2 days compared with unvaccinated patients. Collectively, even if breakthrough infection occurs, the rapid antibody response in fully vaccinated individuals contributes to prevention of severe disease, possibly because of suppression of viral replication.

Rapid Tests for the Diagnosis of Viral Infections

Rapid and accurate diagnostic tests for viral infections are essential for diagnosis, treatment, and patient isolation. Various rapid nucleic acid tests, rapid antigen tests, and rapid antibody tests have been developed and used to diagnose viral infections. In this paper, the types and characteristics of various rapid viral tests currently used in Korea, test items, and considerations when interpreting rapid test results are described.

Direct and Indirect Proof of SARS-CoV-2 Infections in Indigenous Wiwa Communities in North-Eastern Colombia—A Cross-Sectional Assessment Providing Preliminary Surveillance Data

To provide initial data on local SARS-CoV-2 epidemiology and spread in indigenous communities in north-eastern Colombia, respiratory swabs and serum samples from volunteers of indigenous communities were examined in March and April 2021. Samples from non-indigenous Colombians from the same villages were included as well. While previous exposure to SARS-CoV-2 was assessed by analysing serum samples for IgG and IgM with a rapid antibody point-of-care-test (POCT), screening for active infections was carried out with an antigen POCT test and real-time PCR from nasal swabs. In 380 indigenous and 72 non-indigenous volunteers, 61 (13.5%) active infections and an additional 113 (25%) previous infections were identified using diagnostic serology and molecular assays. Previous infections were more frequent in non-indigenous volunteers, and relevant associations of clinical features with active or previous SARS-CoV-2 infections were not observed. Symptoms reported were mild to moderate. SARS-CoV-2 was frequent in the assessed Colombian indigenous communities, as 38.5% of the study participants showed signs of exposure to SARS-CoV-2, which confirms the need to include these indigenous communities in screening and vaccination programs.

The Correlation of Rapid Antibody Results with SARS-CoV-2 PCR in COVID-19 Patients in Ulin General Hospital Banjarmasin

Introduction: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the cause of clinical disease, better known as COVID-19. The most common method to detect COVID-19 is serological testing of IgM and IgG in response to viral infections using rapid diagnostic test (RDT). Several other guidelines consider polymerase chain reaction (PCR) as the gold standard for diagnosis becausePCR has high sensitivity and specificity values in detecting SARS-CoV-2.Methods: This was a descriptive analytical study. The samples were taken from medical records of COVID-19 patients in Ulin General Hospital Banjarmasin from March to October 2020. Statistical Package for the Social Sciences (SPSS) 16.0 software and Chi-Square test were used for data analysis.Results: From 751 COVID-19 patients, 408 patients (54.32%) had rapid antibody with positive PCR, 132 patients (17.57%) had reactive rapid antibody with negative PCR, 152 patients (20.23%) had non-reactive rapid antibody with positive PCR, and 59 patients (7.85%) had non-reactive rapid antibody with negative PCR. The rapid antibody had sensitivity of 72.85% and specificity of 30.89%. From Chi-Square test, reactive rapid antibody was not correlated with PCR positive results; values of p = 0.320, odds ratio (OR) 1.20.Conclusion: The rapid test antibody could not be recommended as a diagnostic tool. In this study, it was also found that there was no relationship between reactive rapid test results and positive SARS-CoV PCR.