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1.
Front Immunol ; 13: 815041, 2022.
Article in English | MEDLINE | ID: covidwho-1952315

ABSTRACT

The role of T cells in the control of SARS-CoV-2 infection has been underestimated in favor of neutralizing antibodies. However, cellular immunity is essential for long-term viral control and protection from disease severity. To understand T-cell immunity in the absence of antibody generation we focused on a group of SARS-CoV-2 Non-Seroconvertors (NSC) recovered from infection. We performed an immune comparative analysis of SARS-CoV-2 infected individuals stratified by the absence or presence of seroconversion and disease severity. We report high levels of total naïve and low effector CD8+ T cells in NSC. Moreover, reduced levels of T-cell activation monitored by PD-1 and activation-induced markers were observed in the context of functional SARS-CoV-2 T-cell responses. Longitudinal data indicate the stability of the NSC phenotype over three months of follow-up after infection. Together, these data characterized distinctive immunological traits in NSC including skewed cellular distribution, low activation and functional SARS-CoV-2 T-cell responses. This data highlights the value of T-cell immune monitoring in populations with low seroconversion rates in response to SARS-CoV-2 infection and vaccination.


Subject(s)
COVID-19 , T-Lymphocytes , Humans , Immunity, Cellular , SARS-CoV-2 , Vaccination
3.
Front Microbiol ; 13: 810576, 2022.
Article in English | MEDLINE | ID: covidwho-1928430

ABSTRACT

The SARS-CoV-2 antigen-detecting rapid diagnostic test (Ag-RDTs) is an easy-to-use diagnostic tool to identify the contagious individuals and reduce the new infections. However, to be effective, Ag-RDTs require the detection of distinct variants of concern (VOC) with high analytical sensitivity. Here, we found that the VOC diverge at the nucleocapsid protein used by four commercial Ag-RDTs for the viral detection. Relative to the original D614G variant, there was a 10-fold loss of detection for the Delta and Alpha variants in certain Ag-RDTs, a reduction above the threshold required to isolate the viable virus. However, Beta and Omicron variants did not lose the detection capacity. As the new VOC arise, successful contact tracing requires continuous monitoring of Ag-RDTs performance.

4.
Viruses ; 14(7)2022 06 24.
Article in English | MEDLINE | ID: covidwho-1911653

ABSTRACT

The implementation of vaccination among healthcare workers (HCWs) allowed the management of the pandemic in a manner that differed from that in the first waves. It has been demonstrated that the mRNA vaccines elicit good humoral responses but that there are still breakthrough infections. In summer 2021, a fifth wave emerged, despite the good coverage of HCWs in Spain. We aimed to study the SARS-CoV-2 IgG antibody levels as a marker to predict the possibility of Delta variant infections after vaccination after a seroepidemiological campaign. Of the 5000 participants, a total of 4902 (98.04%) showed a positive result in the serological anti-S test and only 98 (1.96%) were negative. Among the 4368 fully vaccinated participants, only in five cases was the serology negative. Of the total number of participants that received antibody results during the study, 162 were PCR positive in the subsequent two months. Among these, 151 were fully vaccinated (two doses). Significant differences between antibody BAU/mL levels were found between PCR positive and non-PCR positive participants (p < 0.01). The median of BAU/mL was higher in those vaccinated patients with no infection (1260 BAU/mL; 465-2080) versus infected patients (661 BAU/mL; 361-2080). These data support the idea that vaccines play an important role in the control of the pandemic, especially among HCWs at the time of the Delta variant circulation. More studies with other variants of concern must be performed in order to establish a correlation between the levels of IgG and the new infections.


Subject(s)
COVID-19 Vaccines , COVID-19 , Antibodies, Viral , COVID-19/prevention & control , Follow-Up Studies , Health Personnel , Humans , SARS-CoV-2/genetics , Vaccination
6.
Frontiers in immunology ; 13, 2022.
Article in English | EuropePMC | ID: covidwho-1863963

ABSTRACT

The role of T cells in the control of SARS-CoV-2 infection has been underestimated in favor of neutralizing antibodies. However, cellular immunity is essential for long-term viral control and protection from disease severity. To understand T-cell immunity in the absence of antibody generation we focused on a group of SARS-CoV-2 Non-Seroconvertors (NSC) recovered from infection. We performed an immune comparative analysis of SARS-CoV-2 infected individuals stratified by the absence or presence of seroconversion and disease severity. We report high levels of total naïve and low effector CD8+ T cells in NSC. Moreover, reduced levels of T-cell activation monitored by PD-1 and activation-induced markers were observed in the context of functional SARS-CoV-2 T-cell responses. Longitudinal data indicate the stability of the NSC phenotype over three months of follow-up after infection. Together, these data characterized distinctive immunological traits in NSC including skewed cellular distribution, low activation and functional SARS-CoV-2 T-cell responses. This data highlights the value of T-cell immune monitoring in populations with low seroconversion rates in response to SARS-CoV-2 infection and vaccination.

7.
Front Microbiol ; 13: 840757, 2022.
Article in English | MEDLINE | ID: covidwho-1862623

ABSTRACT

The emerging SARS-CoV-2 variants of concern (VOCs) may display enhanced transmissibility, more severity and/or immune evasion; however, the pathogenesis of these new VOCs in experimental SARS-CoV-2 models or the potential infection of other animal species is not completely understood. Here we infected K18-hACE2 transgenic mice with B.1, B.1.351/Beta, B.1.617.2/Delta and BA.1.1/Omicron isolates and demonstrated heterogeneous infectivity and pathogenesis. B.1.351/Beta variant was the most pathogenic, while BA.1.1/Omicron led to lower viral RNA in the absence of major visible clinical signs. In parallel, we infected wildtype (WT) mice and confirmed that, contrary to B.1 and B.1.617.2/Delta, B.1.351/Beta and BA.1.1/Omicron can infect them. Infection in WT mice coursed without major clinical signs and viral RNA was transient and undetectable in the lungs by day 7 post-infection. In silico modeling supported these findings by predicting B.1.351/Beta receptor binding domain (RBD) mutations result in an increased affinity for both human and murine ACE2 receptors, while BA.1/Omicron RBD mutations only show increased affinity for murine ACE2.

8.
Nat Commun ; 13(1): 2583, 2022 05 11.
Article in English | MEDLINE | ID: covidwho-1839524

ABSTRACT

Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when <20% of recruitment target was achieved. A Bayesian-adaptive individual patient data meta-analysis was implemented. Outpatients aged ≥50 years and symptomatic for ≤7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with ≤5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution. TRIAL REGISTRATION: Clinicaltrials.gov NCT04621123 and NCT04589949. REGISTRATION: NCT04621123 and NCT04589949 on https://www. CLINICALTRIALS: gov.


Subject(s)
COVID-19 , Bayes Theorem , COVID-19/therapy , Humans , Immunization, Passive , Middle Aged , Multicenter Studies as Topic , Outpatients , Randomized Controlled Trials as Topic , SARS-CoV-2 , Treatment Outcome
9.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-329353

ABSTRACT

Background: Understanding the immune response to the SARS-CoV-2 virus is critical for efficient monitoring and defence strategies. The ProHEpic-19 cohort provides a fine-grained description of the kinetics of antibodies after SARS-CoV-2 infection with an exceptional resolution over 17 months.MethodsWe established a cohort of 769 health professionals including healthy and infected with SARS-CoV-2 in northern Barcelona to determine the kinetics of the IgM against the nucleocapsid (N) and the IgG against the N and spike (S) of SARS-CoV-2. We used non-linear mixed models to investigate the kinetics of IgG and IgM measured at nine time points over 17 months from the diagnosis. The model included factors of time, gender, and disease severity (asymptomatic, mild-moderate, severe-critical) to assess their effects and their interactions. Findings: 474 of the 769 participants (61.6%) became infected with SARS-CoV-2. Significant effects of gender and disease severity were found for the levels of all three antibodies. Median IgM(N) levels were already below the positivity threshold in patients with asymptomatic and mild-moderate disease at day 270 after the diagnosis, while IgG(N and S) levels remained positive at least until days 450 and 270, respectively. Kinetic modelling showed a general rise in both IgM(N) and IgG(N) levels up to day 30, followed by a decay with a rate depending on disease severity. IgG(S) levels remained relatively constant from day 15 over time.Interpretation: IgM(N) and IgG(N, S) SARS-CoV-2 antibodies showed a heterogeneous kinetics over the 13 months. Only the IgG(S) showed a stable increase, and the levels and the kinetics of antibodies varied according to disease severity. The kinetics of IgM and IgG observed over a year also varied by clinical spectrum can be very useful for public health policies around vaccination criteria in adult population. Funding Regional Ministry of Health of the Generalitat de Catalunya (Call COVID19-PoC SLT16_04;NCT04885478)

10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-315734

ABSTRACT

The banning of mass-gathering indoor events to prevent SARS-CoV-2 spread cause an important impact on local economies. We designed a randomized-controlled open-label trial to assess the effectiveness of a comprehensive preventive intervention for a mass-gathering indoor event (a live concert) based on systematic screening of attendees with antigen-detecting rapid diagnostic tests, use of facial mask, and adequate air ventilation. According to a RT-PCR test performed on day 8 after the event, none of the 465 assistants in the experimental arm (i.e., event attendants) became infected by SARS-CoV-2 (observed incidence 0%;Bayesian estimated incidence 0.14%;95%CI: 0% to 0.61%) versus 2 out of 495 controls (not entering into the event) (0.31%;95%CI: 0.04% to 0.73%). No significant differences were observed between the estimated incidence in the two study arms. Our study provides evidence on the safety of indoor mass-gathering events conducted during a COVID-19 outbreak under a comprehensive preventive intervention. (ClinicalTrials.gov number, NCT04668625)

12.
Lancet Respir Med ; 10(3): 278-288, 2022 03.
Article in English | MEDLINE | ID: covidwho-1671366

ABSTRACT

BACKGROUND: Convalescent plasma has been proposed as an early treatment to interrupt the progression of early COVID-19 to severe disease, but there is little definitive evidence. We aimed to assess whether early treatment with convalescent plasma reduces the risk of hospitalisation and reduces SARS-CoV-2 viral load among outpatients with COVID-19. METHODS: We did a multicentre, double-blind, randomised, placebo-controlled trial in four health-care centres in Catalonia, Spain. Adult outpatients aged 50 years or older with the onset of mild COVID-19 symptoms 7 days or less before randomisation were eligible for enrolment. Participants were randomly assigned (1:1) to receive one intravenous infusion of either 250-300 mL of ABO-compatible high anti-SARS-CoV-2 IgG titres (EUROIMMUN ratio ≥6) methylene blue-treated convalescent plasma (experimental group) or 250 mL of sterile 0·9% saline solution (control). Randomisation was done with the use of a central web-based system with concealment of the trial group assignment and no stratification. To preserve masking, we used opaque tubular bags that covered the investigational product and the infusion catheter. The coprimary endpoints were the incidence of hospitalisation within 28 days from baseline and the mean change in viral load (in log10 copies per mL) in nasopharyngeal swabs from baseline to day 7. The trial was stopped early following a data safety monitoring board recommendation because more than 85% of the target population had received a COVID-19 vaccine. Primary efficacy analyses were done in the intention-to-treat population, safety was assessed in all patients who received the investigational product. This study is registered with ClinicalTrials.gov, NCT04621123. FINDINGS: Between Nov 10, 2020, and July 28, 2021, we assessed 909 patients with confirmed COVID-19 for inclusion in the trial, 376 of whom were eligible and were randomly assigned to treatment (convalescent plasma n=188 [serum antibody-negative n=160]; placebo n=188 [serum antibody-negative n=166]). Median age was 56 years (IQR 52-62) and the mean symptom duration was 4·4 days (SD 1·4) before random assignment. In the intention-to-treat population, hospitalisation within 28 days from baseline occurred in 22 (12%) participants who received convalescent plasma versus 21 (11%) who received placebo (relative risk 1·05 [95% CI 0·78 to 1·41]). The mean change in viral load from baseline to day 7 was -2·41 log10 copies per mL (SD 1·32) with convalescent plasma and -2·32 log10 copies per mL (1·43) with placebo (crude difference -0·10 log10 copies per mL [95% CI -0·35 to 0·15]). One participant with mild COVID-19 developed a thromboembolic event 7 days after convalescent plasma infusion, which was reported as a serious adverse event possibly related to COVID-19 or to the experimental intervention. INTERPRETATION: Methylene blue-treated convalescent plasma did not prevent progression from mild to severe illness and did not reduce viral load in outpatients with COVID-19. Therefore, formal recommendations to support the use of convalescent plasma in outpatients with COVID-19 cannot be concluded. FUNDING: Grifols, Crowdfunding campaign YoMeCorono.


Subject(s)
COVID-19 , Methylene Blue , Adult , COVID-19/therapy , COVID-19 Vaccines , Double-Blind Method , Humans , Immunization, Passive , Middle Aged , Outpatients , SARS-CoV-2 , Treatment Outcome
13.
Front Public Health ; 9: 788581, 2021.
Article in English | MEDLINE | ID: covidwho-1648288

ABSTRACT

Background: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) antigen (Ag) tests have been widely employed to identify patients for a rapid diagnosis and pandemic control. Rapid lateral-flow techniques are currently the most used, but automated technologies have emerged as another viable alternative to molecular methods. We aimed to evaluate the analytical performance of the DiaSorin Liaison SARS-CoV-2 Ag test in asymptomatic population and close contacts, for its use as a tool in pandemic control efforts. Material and Methods: A retrospective study was conducted. A total of 861 samples were included, 291 (34%) were positive for SARS-CoV-2 with cycle threshold (Ct) <40, and 570 (66%) were negative. Results: A strong correlation was observed between reverse transcriptase-PCR (RT-PCR) Ct and Ag 50% Tissue Culture Infectious Dose per milliliter (TCID50/ml; r = 0.6486; p < 0.0001) and all RT-PCR negative samples tested negative for the 200 TCID50/ml SARS-Cov-2 Ag cutoff, i.e., a specificity of 100% was reached (95% CI: 99.4-100.0%). Samples with <25 Ct and/or >106 extrapolated copies/ml were reached a sensitivity of 100% (95% IC 97.0-100.0%). For intermediate viral loads (>105 extrapolated copies/ml or <30 Ct), the sensitivity value still exceeded 80%. As with other Ag methods, samples between 30 and 40 Ct could not be detected with a reliable sensitivity. Conclusions: The LIAISON® SARS-CoV-2 Ag assay displays an acceptable sensitivity and a very high specificity that is useful for detecting the presence of SARS-CoV-2 in nasal swabs (NPS) of asymptomatic population or to regular monitoring of risk groups in controlled settings. Additionally, the flexibility in processing different samples and in the sampling preparation process makes this test an option for its use in high throughput laboratories. Automated tests may facilitate result reporting and yield consistent data, while avoiding some of the pitfalls of rapid lateral-flow techniques, such as observer variability.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Pandemics , Retrospective Studies , Sensitivity and Specificity
14.
Lancet Infect Dis ; 21(10): 1365-1372, 2021 10.
Article in English | MEDLINE | ID: covidwho-1597413

ABSTRACT

BACKGROUND: The banning of mass-gathering indoor events to prevent SARS-CoV-2 spread has had an important effect on local economies. Despite growing evidence on the suitability of antigen-detecting rapid diagnostic tests (Ag-RDT) for mass screening at the event entry, this strategy has not been assessed under controlled conditions. We aimed to assess the effectiveness of a prevention strategy during a live indoor concert. METHODS: We designed a randomised controlled open-label trial to assess the effectiveness of a comprehensive preventive intervention for a mass-gathering indoor event (a live concert) based on systematic same-day screening of attendees with Ag-RDTs, use of facial masks, and adequate air ventilation. The event took place in the Sala Apolo, Barcelona, Spain. Adults aged 18-59 years with a negative result in an Ag-RDT from a nasopharyngeal swab collected immediately before entering the event were randomised 1:1 (block randomisation stratified by age and gender) to either attend the indoor event for 5 hours or go home. Nasopharyngeal specimens used for Ag-RDT screening were analysed by real-time reverse-transcriptase PCR (RT-PCR) and cell culture (Vero E6 cells). 8 days after the event, a nasopharyngeal swab was collected and analysed by Ag-RDT, RT-PCR, and a transcription-mediated amplification test (TMA). The primary outcome was the difference in incidence of RT-PCR-confirmed SARS-CoV-2 infection at 8 days between the control and the intervention groups, assessed in all participants who were randomly assigned, attended the event, and had a valid result for the SARS-CoV-2 test done at follow-up. The trial is registered at ClinicalTrials.gov, NCT04668625. FINDINGS: Participant enrollment took place during the morning of the day of the concert, Dec 12, 2020. Of the 1140 people who responded to the call and were deemed eligible, 1047 were randomly assigned to either enter the music event (experimental group) or continue with normal life (control group). Of the 523 randomly assigned to the experimental group, 465 were included in the analysis of the primary outcome (51 did not enter the event and eight did not take part in the follow-up assessment), and of the 524 randomly assigned to the control group, 495 were included in the final analysis (29 did not take part in the follow-up). At baseline, 15 (3%) of 495 individuals in the control group and 13 (3%) of 465 in the experimental group tested positive on TMA despite a negative Ag-RDT result. The RT-PCR test was positive in one case in each group and cell viral culture was negative in all cases. 8 days after the event, two (<1%) individuals in the control arm had a positive Ag-RDT and PCR result, whereas no Ag-RDT nor RT-PCR positive results were found in the intervention arm. The Bayesian estimate for the incidence between the experimental and control groups was -0·15% (95% CI -0·72 to 0·44). INTERPRETATION: Our study provides preliminary evidence on the safety of indoor mass-gathering events during a COVID-19 outbreak under a comprehensive preventive intervention. The data could help restart cultural activities halted during COVID-19, which might have important sociocultural and economic implications. FUNDING: Primavera Sound Group and the #YoMeCorono Initiative. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19 , Adolescent , Adult , COVID-19/diagnosis , COVID-19/epidemiology , Humans , Mass Screening , Middle Aged , Reproducibility of Results , Spain , Young Adult
15.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-293378

ABSTRACT

Background: Convalescent plasma (CP) for hospitalized patients with COVID-19 has not demonstrated clear benefits. However, data on outpatients with early symptoms are scarce. We aimed to assess whether treatment with CP administered during the first 7 days of symptoms reduced the disease progression or risk of hospitalization of outpatients. Methods: Two double-blind randomized trials ( NCT04621123 , NCT04589949 ) were merged with data pooling starting when <20% of their predefined sample size had been recruited. A Bayesian adaptive individual patient data meta-analysis was implemented. Analyses were done with Bayesian proportional odds and logistic models, where odds ratios (OR)<1.0 indicate a favorable outcome for CP. Fourteen study sites across the Netherlands and Catalonia in Spain participated in the trial. The two studies included outpatients aged ≥50 years and diagnosed with COVID-19 and symptomatic for ≤7days. The intervention consisted of one unit (200-300mL) of CP with a predefined minimum level of antibodies. The two primary endpoints were (a) a 5-point disease severity scale (fully recovered by day 7 or not, hospital or ICU admission and death) and (b) a composite of hospitalization or death. Results: Of 797 patients included, 390 received CP and 392 placebo. At baseline, they had a median age of 58 years, 1 comorbidity, symptoms for 5 days and 93% tested negative for SARS-CoV-2 S-protein IgG antibodies. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The OR of CP for an improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311). The OR for hospitalization or death was 0.919 (CI 0.592-1.416). The effect of CP on hospital admission or death was largest in patients with ≤5 days of symptoms (OR 0.658, 95% CI 0.394-1.085). CP did not decrease the time to full symptom resolution (p=0.62). Conclusion: Treatment with CP of outpatients in the first 7 days of symptoms did not improve the outcome of COVID-19. The possible beneficial effect in patients with ≤5 days of symptoms requires further study.   Registration: NCT04621123 and NCT04589949 on https://www.clinicaltrials.gov

18.
Int J Environ Res Public Health ; 18(13)2021 06 30.
Article in English | MEDLINE | ID: covidwho-1288889

ABSTRACT

BACKGROUND: The epidemiological situation generated by COVID-19 has highlighted the importance of applying non-pharmacological measures in the management of the epidemic. Mass screening of the asymptomatic general population has been established as a priority strategy by carrying out diagnostic tests to detect possible cases, isolate contacts, cut transmission chains and thus limit the spread of the virus. OBJECTIVE: To evaluate the economic impact of mass COVID-19 screenings of an asymptomatic population during the first and second wave of the epidemic in Catalonia, Spain. METHODOLOGY: Cost-Benefit Analysis based on the estimated total costs of mass screening versus health gains and associated health costs avoided. RESULTS: Excluding the value of monetized health, the Benefit-Cost ratio was estimated at 0.45, a low value that would seem to advise against mass screening policies. However, if monetized health is included, the ratio is close to 1.20, reversing the interpretation. In other words, the monetization of health is the critical element that tips the scales in favour of the desirability of screening. Results show that the interventions with the highest return are those that maximize the percentage of positives detected. CONCLUSION: Efficient management of resources for the policy of mass screening in asymptomatic populations can generate high social returns. The positivity rate critically determines its desirability. Likewise, precocity in the detection of cases will cut more transmissions in the chain of contagion and increase the economic return of these interventions. Maximizing the value of resources depends on screening strategies being accompanied by contact-tracing and specific in their focus, targeting, for example, high-risk subpopulations with the highest rate of expected positives.


Subject(s)
COVID-19 , Contact Tracing , Cost-Benefit Analysis , Humans , SARS-CoV-2 , Spain/epidemiology
19.
Viruses ; 13(6)2021 06 12.
Article in English | MEDLINE | ID: covidwho-1270125

ABSTRACT

With the spread of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is a need to assess the protection conferred by both previous infections and current vaccination. Here we tested the neutralizing activity of infected and/or vaccinated individuals against pseudoviruses expressing the spike of the original SARS-CoV-2 isolate Wuhan-Hu-1 (WH1), the D614G mutant and the B.1.1.7 variant. Our data show that parameters of natural infection (time from infection and nature of the infecting variant) determined cross-neutralization. Uninfected vaccinees showed a small reduction in neutralization against the B.1.1.7 variant compared to both the WH1 strain and the D614G mutant. Interestingly, upon vaccination, previously infected individuals developed more robust neutralizing responses against B.1.1.7, suggesting that vaccines can boost the neutralization breadth conferred by natural infection.


Subject(s)
Antibodies, Neutralizing/blood , COVID-19 Vaccines/immunology , COVID-19/immunology , Neutralization Tests/statistics & numerical data , SARS-CoV-2/immunology , Vaccination/statistics & numerical data , Adult , Aged , Aged, 80 and over , Antibodies, Viral/immunology , COVID-19/blood , COVID-19 Serological Testing/statistics & numerical data , COVID-19 Vaccines/administration & dosage , Cross Reactions/immunology , Female , Humans , Immunity, Humoral , Male , Middle Aged , Prospective Studies , SARS-CoV-2/genetics
20.
J Infect ; 82(6): 269-275, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1188792

ABSTRACT

BACKGROUND: Mass testing for early identification and isolation of infectious COVID-19 individuals is efficacious for reducing disease spread. Antigen-detecting rapid diagnostic tests (Ag-RDT) may be suitable for testing strategies; however, benchmark comparisons are scarce. METHODS: We used 286 nasopharyngeal specimens from unexposed asymptomatic individuals collected between December 2020 and January 2021 to assess five Ag-RDTs marketed by Abbott, Siemens, Roche Diagnostics, Lepu Medical, and Surescreen. RESULTS: For the overall sample, the performance parameters of Ag-RDTs were as follows: Abbott assay, sensitivity 38.6% (95%CI 29.1-48.8) and specificity 99.5% (97-100%); Siemens, sensitivity 51.5% (41.3-61.6) and specificity 98.4% (95.3-99.6); Roche, sensitivity 43.6% (33.7-53.8) and specificity 96.2% (92.4-98.5); Lepu, sensitivity 45.5% (35.6-55.8) and specificity 89.2% (83.8-93.3%); Surescreen, sensitivity 28.8% (20.2-38.6) and specificity 97.8% (94.5-99.4%). For specimens with cycle threshold (Ct) <30 in RT-qPCR, all Ag-RDT achieved a sensitivity ≥70%. The modelled negative- and positive-predictive value for 1% prevalence were >99% and <50%, respectively. CONCLUSIONS: When screening unexposed asymptomatic individuals, two Ag-RDTs achieved sensitivity ≥80% for specimens with Ct<30 and specificity ≥96%. The estimated negative predictive value suggests the suitability of Ag-RDTs for mass screenings of SARS-CoV-2 infection in the general population.


Subject(s)
COVID-19 , SARS-CoV-2 , Antigens, Viral , Asymptomatic Infections , Benchmarking , Diagnostic Tests, Routine , Humans , Sensitivity and Specificity , Silver
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