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  1. Article ; Online: The timing of HIV-1 infection of cells that persist on therapy is not strongly influenced by replication competency or cellular tropism of the provirus.

    Joseph, Sarah B / Abrahams, Melissa-Rose / Moeser, Matthew / Tyers, Lynn / Archin, Nancie M / Council, Olivia D / Sondgeroth, Amy / Spielvogel, Ean / Emery, Ann / Zhou, Shuntai / Doolabh, Deelan / Ismail, Sherazaan D / Karim, Salim Abdool / Margolis, David M / Pond, Sergei Kosakovsky / Garrett, Nigel / Swanstrom, Ronald / Williamson, Carolyn

    PLoS pathogens

    2024  Volume 20, Issue 2, Page(s) e1011974

    Abstract: People with HIV-1 (PWH) on antiretroviral therapy (ART) can maintain undetectable virus levels, but a small pool of infected cells persists. This pool is largely comprised of defective proviruses that may produce HIV-1 proteins but are incapable of ... ...

    Abstract People with HIV-1 (PWH) on antiretroviral therapy (ART) can maintain undetectable virus levels, but a small pool of infected cells persists. This pool is largely comprised of defective proviruses that may produce HIV-1 proteins but are incapable of making infectious virus, with only a fraction (~10%) of these cells harboring intact viral genomes, some of which produce infectious virus following ex vivo stimulation (i.e. inducible intact proviruses). A majority of the inducible proviruses that persist on ART are formed near the time of therapy initiation. Here we compared proviral DNA (assessed here as 3' half genomes amplified from total cellular DNA) and inducible replication competent viruses in the pool of infected cells that persists during ART to determine if the original infection of these cells occurred at comparable times prior to therapy initiation. Overall, the average percent of proviruses that formed late (i.e. around the time of ART initiation, 60%) did not differ from the average percent of replication competent inducible viruses that formed late (69%), and this was also true for proviral DNA that was hypermutated (57%). Further, there was no evidence that entry into the long-lived infected cell pool was impeded by the ability to use the CXCR4 coreceptor, nor was the formation of long-lived infected cells enhanced during primary infection, when viral loads are exceptionally high. We observed that infection of cells that transitioned to be long-lived was enhanced among people with a lower nadir CD4+ T cell count. Together these data suggest that the timing of infection of cells that become long-lived is impacted more by biological processes associated with immunodeficiency before ART than the replication competency and/or cellular tropism of the infecting virus or the intactness of the provirus. Further research is needed to determine the mechanistic link between immunodeficiency and the timing of infected cells transitioning to the long-lived pool, particularly whether this is due to differences in infected cell clearance, turnover rates and/or homeostatic proliferation before and after ART.
    MeSH term(s) Humans ; Proviruses/genetics ; HIV-1/genetics ; Anti-Retroviral Agents/pharmacology ; Anti-Retroviral Agents/therapeutic use ; HIV Infections/drug therapy ; CD4-Positive T-Lymphocytes ; DNA, Viral/genetics ; DNA, Viral/metabolism ; Viral Load ; Tropism
    Chemical Substances Anti-Retroviral Agents ; DNA, Viral
    Language English
    Publishing date 2024-02-29
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2205412-1
    ISSN 1553-7374 ; 1553-7374
    ISSN (online) 1553-7374
    ISSN 1553-7374
    DOI 10.1371/journal.ppat.1011974
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Improved oral detection is a characteristic of Omicron infection and has implications for clinical sampling and tissue tropism.

    Marais, Gert / Hsiao, Nei-Yuan / Iranzadeh, Arash / Doolabh, Deelan / Joseph, Rageema / Enoch, Annabel / Chu, Chun-Yat / Williamson, Carolyn / Brink, Adrian / Hardie, Diana

    Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology

    2022  Volume 152, Page(s) 105170

    Abstract: Background: The Omicron variant of concern is characterised by more than 50 distinct mutations, most in the spike protein. The implications of these for disease transmission, tissue tropism and diagnostic testing needs study.: Objectives: We ... ...

    Abstract Background: The Omicron variant of concern is characterised by more than 50 distinct mutations, most in the spike protein. The implications of these for disease transmission, tissue tropism and diagnostic testing needs study.
    Objectives: We evaluated the performance of RT-PCR on saliva (SA) swabs and antigen testing on mid-turbinate MT samples relative to RT-PCR on MT swabs. Patients (n = 453) presenting for outpatient testing at the Groote Schuur Hospital COVID-19 testing centre in Cape Town South Africa were recruited. Participants were recruited during the Delta (n = 304) and Omicron (n = 149) waves.
    Results: In 30 confirmed Delta infections, positive percent agreement (PPA) of RT-PCR on saliva was only 73% compared to a composite standard of either MT or SA RT-PCR positivity, with rapid decay by day 3 after symptom onset. In contrast, in the 70 Omicron infections, SA performed as well as, or better than, MT samples up to day 5, with an overall PPA of SA swabs of 96% and MT of 93%. A change in antigen test performance was noted, with PPA of 93% in Delta, but only 68% for Omicron.
    Conclusions: Altered shedding kinetics appear to be present in Omicron-infected patients with more viral RNA detectable in saliva. Saliva swabs are a promising alternative to nasal samples, especially early in infection when sampling of both sites could improve detection. Lower sensitivity of antigen tests in Omicron is a concern and requires further study.
    MeSH term(s) COVID-19 ; COVID-19 Testing ; Humans ; SARS-CoV-2 ; Sensitivity and Specificity ; South Africa ; Tropism
    Language English
    Publishing date 2022-05-01
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1446080-4
    ISSN 1873-5967 ; 1386-6532
    ISSN (online) 1873-5967
    ISSN 1386-6532
    DOI 10.1016/j.jcv.2022.105170
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Performance of saliva and mid-turbinate swabs for detection of the beta variant in South Africa.

    Chu, Chun Yat / Marais, Gert / Opperman, Christoffel / Doolabh, Deelan / Iranzadeh, Arash / Marais, Carisa / Cox, Helen / Williamson, Carolyn / Hardie, Diana / Brink, Adrian

    The Lancet. Infectious diseases

    2021  Volume 21, Issue 10, Page(s) 1354

    MeSH term(s) COVID-19/diagnosis ; COVID-19/virology ; COVID-19 Testing/methods ; Humans ; Nasopharynx/virology ; Polymerase Chain Reaction ; SARS-CoV-2/classification ; SARS-CoV-2/genetics ; SARS-CoV-2/isolation & purification ; Saliva/virology ; South Africa ; Specimen Handling/methods ; Turbinates/virology
    Language English
    Publishing date 2021-08-04
    Publishing country United States
    Document type Comparative Study ; Letter ; Research Support, Non-U.S. Gov't
    ZDB-ID 2061641-7
    ISSN 1474-4457 ; 1473-3099
    ISSN (online) 1474-4457
    ISSN 1473-3099
    DOI 10.1016/S1473-3099(21)00405-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Reduced amplification efficiency of the RNA-dependent-RNA-polymerase target enables tracking of the Delta SARS-CoV-2 variant using routine diagnostic tests

    Valley-Omar, Ziyaad / Marais, Gert / Iranzadeh, Arash / Naidoo, Michelle / Korsman, Stephen / Maponga, Tongai / Hussey, Hannah / Davies, Mary-Ann / Boulle, Andrew / Doolabh, Deelan / Laubscher, Mariska / Wojno, Justyna / Deetlefs, J.D. / Maritz, Jean / Scott, Lesley / Msomi, Nokukhanya / Naicker, Cherise / Tegally, Houriiyah / de Oliveira, Tulio /
    Bhiman, Jinal / Williamson, Carolyn / Preiser, Wolfgang / Hardie, Diana / Hsiao, Nei-yuan

    Journal of virological methods. 2022 Apr., v. 302

    2022  

    Abstract: Routine SARS-CoV-2 surveillance in the Western Cape region of South Africa (January-August 2021) found a reduced RT-PCR amplification efficiency of the RdRp-gene target of the Seegene, Allplex 2019-nCoV diagnostic assay from June 2021 when detecting the ... ...

    Abstract Routine SARS-CoV-2 surveillance in the Western Cape region of South Africa (January-August 2021) found a reduced RT-PCR amplification efficiency of the RdRp-gene target of the Seegene, Allplex 2019-nCoV diagnostic assay from June 2021 when detecting the Delta variant. We investigated whether the reduced amplification efficiency denoted by an increased RT-PCR cycle threshold value (RΔE) can be used as an indirect measure of SARS-CoV-2 Delta variant prevalence. We found a significant increase in the median RΔE for patient samples tested from June 2021, which coincided with the emergence of the SARS-CoV-2 Delta variant within our sample set. Whole genome sequencing on a subset of patient samples identified a highly conserved G15451A, non-synonymous mutation exclusively within the RdRp gene of Delta variants, which may cause reduced RT-PCR amplification efficiency. While whole genome sequencing plays an important in identifying novel SARS-CoV-2 variants, monitoring RΔE value can serve as a useful surrogate for rapid tracking of Delta variant prevalence.
    Keywords Severe acute respiratory syndrome coronavirus 2 ; genes ; monitoring ; mutation ; patients ; South Africa
    Language English
    Dates of publication 2022-04
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 8013-5
    ISSN 1879-0984 ; 0166-0934
    ISSN (online) 1879-0984
    ISSN 0166-0934
    DOI 10.1016/j.jviromet.2022.114471
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: Higher mortality associated with the SARS-CoV-2 Delta variant in the Western Cape, South Africa, using RdRp target delay as a proxy: a cross-sectional study.

    Hussey, Hannah / Davies, Mary-Ann / Heekes, Alexa / Williamson, Carolyn / Valley-Omar, Ziyaad / Hardie, Diana / Korsman, Stephen / Doolabh, Deelan / Preiser, Wofgang / Maponga, Tongai / Iranzadeh, Arash / Engelbrecht, Susan / Wasserman, Sean / Schrueder, Neshaad / Boloko, Linda / Symons, Greg / Raubenheimer, Peter / Viljoen, Abraham / Parker, Arifa /
    Cohen, Cheryl / Jasat, Waasila / Lessells, Richard / Wilkinson, Robert J / Boulle, Andrew / Hsiao, Marvin

    Gates open research

    2022  Volume 6, Page(s) 117

    Abstract: Background: ...

    Abstract Background:
    Language English
    Publishing date 2022-08-31
    Publishing country United States
    Document type Journal Article
    ISSN 2572-4754
    ISSN (online) 2572-4754
    DOI 10.12688/gatesopenres.13654.1
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Assessing the clinical severity of the Omicron variant in the Western Cape Province, South Africa, using the diagnostic PCR proxy marker of RdRp target delay to distinguish between Omicron and Delta infections - a survival analysis.

    Hussey, Hannah / Davies, Mary-Ann / Heekes, Alexa / Williamson, Carolyn / Valley-Omar, Ziyaad / Hardie, Diana / Korsman, Stephen / Doolabh, Deelan / Preiser, Wolfgang / Maponga, Tongai / Iranzadeh, Arash / Wasserman, Sean / Boloko, Linda / Symons, Greg / Raubenheimer, Peter / Parker, Arifa / Schrueder, Neshaad / Solomon, Wesley / Rousseau, Petro /
    Wolter, Nicole / Jassat, Waasila / Cohen, Cheryl / Lessells, Richard / Wilkinson, Robert J / Boulle, Andrew / Hsiao, Nei-Yuan

    International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases

    2022  Volume 118, Page(s) 150–154

    Abstract: Background: At present, it is unclear whether the extent of reduced risk of severe disease seen with SARS-Cov-2 Omicron variant infection is caused by a decrease in variant virulence or by higher levels of population immunity.: Methods: RdRp target ... ...

    Abstract Background: At present, it is unclear whether the extent of reduced risk of severe disease seen with SARS-Cov-2 Omicron variant infection is caused by a decrease in variant virulence or by higher levels of population immunity.
    Methods: RdRp target delay (RTD) in the Seegene Allplex
    Results: A total of 150 cases with RTD and 1486 cases without RTD were included. Cases without RTD had a lower hazard of admission (adjusted hazard ratio [aHR], 0.56; 95% confidence interval [CI], 0.34-0.91). Complete vaccination was protective against admission, with an aHR of 0.45 (95% CI, 0.26-0.77).
    Conclusion: Omicron has resulted in a lower risk of hospital admission compared with contemporaneous Delta infection, when using the proxy marker of RTD. Under-ascertainment of reinfections with an immune escape variant remains a challenge to accurately assessing variant virulence.
    MeSH term(s) COVID-19/diagnosis ; Hepatitis D ; Humans ; Polymerase Chain Reaction ; RNA-Dependent RNA Polymerase ; SARS-CoV-2/genetics ; South Africa/epidemiology ; Survival Analysis
    Chemical Substances RNA-Dependent RNA Polymerase (EC 2.7.7.48)
    Language English
    Publishing date 2022-02-27
    Publishing country Canada
    Document type Journal Article
    ZDB-ID 1331197-9
    ISSN 1878-3511 ; 1201-9712
    ISSN (online) 1878-3511
    ISSN 1201-9712
    DOI 10.1016/j.ijid.2022.02.051
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Reduced amplification efficiency of the RNA-dependent-RNA-polymerase target enables tracking of the Delta SARS-CoV-2 variant using routine diagnostic tests.

    Valley-Omar, Ziyaad / Marais, Gert / Iranzadeh, Arash / Naidoo, Michelle / Korsman, Stephen / Maponga, Tongai / Hussey, Hannah / Davies, Mary-Ann / Boulle, Andrew / Doolabh, Deelan / Laubscher, Mariska / Wojno, Justyna / Deetlefs, J D / Maritz, Jean / Scott, Lesley / Msomi, Nokukhanya / Naicker, Cherise / Tegally, Houriiyah / de Oliveira, Tulio /
    Bhiman, Jinal / Williamson, Carolyn / Preiser, Wolfgang / Hardie, Diana / Hsiao, Nei-Yuan

    Journal of virological methods

    2022  Volume 302, Page(s) 114471

    Abstract: Routine SARS-CoV-2 surveillance in the Western Cape region of South Africa (January-August 2021) found a reduced RT-PCR amplification efficiency of the RdRp-gene target of the Seegene, Allplex 2019-nCoV diagnostic assay from June 2021 when detecting the ... ...

    Abstract Routine SARS-CoV-2 surveillance in the Western Cape region of South Africa (January-August 2021) found a reduced RT-PCR amplification efficiency of the RdRp-gene target of the Seegene, Allplex 2019-nCoV diagnostic assay from June 2021 when detecting the Delta variant. We investigated whether the reduced amplification efficiency denoted by an increased RT-PCR cycle threshold value (RΔE) can be used as an indirect measure of SARS-CoV-2 Delta variant prevalence. We found a significant increase in the median RΔE for patient samples tested from June 2021, which coincided with the emergence of the SARS-CoV-2 Delta variant within our sample set. Whole genome sequencing on a subset of patient samples identified a highly conserved G15451A, non-synonymous mutation exclusively within the RdRp gene of Delta variants, which may cause reduced RT-PCR amplification efficiency. While whole genome sequencing plays an important in identifying novel SARS-CoV-2 variants, monitoring RΔE value can serve as a useful surrogate for rapid tracking of Delta variant prevalence.
    MeSH term(s) COVID-19/diagnosis ; COVID-19/virology ; COVID-19 Nucleic Acid Testing ; Diagnostic Tests, Routine ; Humans ; RNA ; RNA-Dependent RNA Polymerase ; SARS-CoV-2/genetics
    Chemical Substances RNA (63231-63-0) ; RNA-Dependent RNA Polymerase (EC 2.7.7.48)
    Language English
    Publishing date 2022-01-18
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 8013-5
    ISSN 1879-0984 ; 0166-0934
    ISSN (online) 1879-0984
    ISSN 0166-0934
    DOI 10.1016/j.jviromet.2022.114471
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Improved performance of saliva for the detection of the B.1.351 variant in South Africa

    Chu, Chun Yat / Marais, Gert / Opperman, Christoffel / Doolabh, Deelan / Iranzadeh, Arash / Marais, Carisa / Cox, Helen / Williamson, Carolyn / Hardie, Diana Ruth / Brink, Adrian

    medRxiv

    Abstract: Assessment of the unknown performance of saliva for the detection of the novel SARS-CoV-2 variant of concern (VOC) B.1.351 (501Y.V2) lineage is essential as saliva has been shown to be an equivalent, less invasive and a less costly alternative to ... ...

    Abstract Assessment of the unknown performance of saliva for the detection of the novel SARS-CoV-2 variant of concern (VOC) B.1.351 (501Y.V2) lineage is essential as saliva has been shown to be an equivalent, less invasive and a less costly alternative to nasopharyngeal swabs for the molecular detection of SARS-CoV-2 infection in pre-variant studies. Between 1st August 2020 and 16th January 2021, we enrolled 410 eligible ambulatory participants who presented to Groote Schuur Hospital (GSH) in Cape Town, South Africa for SARS-CoV-2 testing. Of these, 300 were enrolled prior to, and 110 after, the initial detection and replacement of wild-type by the B.1.351 variant. All participants provided a supervised self-collected mid-turbinate (MT) and saliva (SA) swab, in addition to the standard HCW collected NP swab which were all tested by RT-PCR in an accredited diagnostic laboratory. Positive percent agreement to NP swab for SA swabs pre- and post-variant were 51.5% and 72.5% respectively while these values for MT swabs were 75.8% and 77.5%. The negative percent agreement for all swab types during all periods was >98%. The basis for this marked improvement of SA swabs as a diagnostic sample for B.1.351 virus is still being investigated.
    Keywords covid19
    Language English
    Publishing date 2021-03-31
    Publisher Cold Spring Harbor Laboratory Press
    Document type Article ; Online
    DOI 10.1101/2021.03.29.21254563
    Database COVID19

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  9. Article ; Online: Severity and inpatient mortality of COVID-19 pneumonia from Beta variant infection: a clinical cohort study in Cape Town, South Africa

    Boloko, Linda / Lifson, Aimee / Little, Francesca / De Wet, Timothy / Papavarnavas, Nectarios / Marais, Gert / Hsiao, Nei-yuan / Roslee, Michael-John / Doolabh, Deelan / Iranzadeh, Arash / Williamson, Carolyn / Dlamini, Sipho / Mendelson, Marc / Ntusi, Ntobeko / Wilkinson, Robert / Hussey, Hannah / Davies, Mary-Ann / Meintjes, Graeme / Wasserman, Sean

    medRxiv

    Abstract: Background The SARS-CoV-2 Beta variant, associated with immune escape and higher transmissibility, drove a more severe second COVID-19 wave in South Africa. Individual patient level characteristics and outcomes with the Beta variant are not well ... ...

    Abstract Background The SARS-CoV-2 Beta variant, associated with immune escape and higher transmissibility, drove a more severe second COVID-19 wave in South Africa. Individual patient level characteristics and outcomes with the Beta variant are not well characterized. Methods We performed a retrospective cohort study comparing disease severity and inpatient mortality of COVID-19 pneumonia between the first and second wave periods at a referral hospital in Cape Town, South Africa. Beta variant infection was confirmed by genomic sequencing. Outcomes were analyzed with logistic regression and accelerated failure time models. Results 1,182 patients were included: 571 during the first wave period and 611 from the second wave. Beta variant accounted for 97% of infections in the second wave. There was no difference in crude in-hospital mortality between wave periods (first wave 22.2%, second wave 22.1%; p = 0.9). Time to death was decreased with higher weekly hospital admissions (16%; 95% CI, 8 to 24 for every 50-patient increase), age (18%; 95% CI, 12 to 24 for every 10-year increase) and hypertension (31%; 95% CI, 12 to 46). Corticosteroid use delayed time to death by 2-fold (95% CI, 1.5 to 3.0). Admission during the second wave decreased time to death after adjustment for other predictors, but this did not reach statistical significance (24%; 95% CI, 47 to -2). There was no effect of HIV on survival. Conclusions There was a trend towards earlier mortality during the second COVID-19 wave driven by the Beta variant, suggesting a possible biological basis. Use of oral prednisone was strongly protective.
    Keywords covid19
    Language English
    Publishing date 2021-11-04
    Publisher Cold Spring Harbor Laboratory Press
    Document type Article ; Online
    DOI 10.1101/2021.11.04.21265916
    Database COVID19

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  10. Article ; Online: Escape from recognition of SARS-CoV-2 variant spike epitopes but overall preservation of T cell immunity.

    Riou, Catherine / Keeton, Roanne / Moyo-Gwete, Thandeka / Hermanus, Tandile / Kgagudi, Prudence / Baguma, Richard / Valley-Omar, Ziyaad / Smith, Mikhail / Tegally, Houriiyah / Doolabh, Deelan / Iranzadeh, Arash / Tyers, Lynn / Mutavhatsindi, Hygon / Tincho, Marius B / Benede, Ntombi / Marais, Gert / Chinhoyi, Lionel R / Mennen, Mathilda / Skelem, Sango /
    du Bruyn, Elsa / Stek, Cari / de Oliveira, Tulio / Williamson, Carolyn / Moore, Penny L / Wilkinson, Robert J / Ntusi, Ntobeko A B / Burgers, Wendy A

    Science translational medicine

    2022  Volume 14, Issue 631, Page(s) eabj6824

    Abstract: SARS-CoV-2 variants that escape neutralization and potentially affect vaccine efficacy have emerged. T cell responses play a role in protection from reinfection and severe disease, but the potential for spike mutations to affect T cell immunity is ... ...

    Abstract SARS-CoV-2 variants that escape neutralization and potentially affect vaccine efficacy have emerged. T cell responses play a role in protection from reinfection and severe disease, but the potential for spike mutations to affect T cell immunity is incompletely understood. We assessed neutralizing antibody and T cell responses in 44 South African COVID-19 patients either infected with the Beta variant (dominant from November 2020 to May 2021) or infected before its emergence (first wave, Wuhan strain) to provide an overall measure of immune evasion. We show that robust spike-specific CD4 and CD8 T cell responses were detectable in Beta-infected patients, similar to first-wave patients. Using peptides spanning the Beta-mutated regions, we identified CD4 T cell responses targeting the wild-type peptides in 12 of 22 first-wave patients, all of whom failed to recognize corresponding Beta-mutated peptides. However, responses to mutated regions formed only a small proportion (15.7%) of the overall CD4 response, and few patients (3 of 44) mounted CD8 responses that targeted the mutated regions. Among the spike epitopes tested, we identified three epitopes containing the D215, L18, or D80 residues that were specifically recognized by CD4 T cells, and their mutated versions were associated with a loss of response. This study shows that despite loss of recognition of immunogenic CD4 epitopes, CD4 and CD8 T cell responses to Beta are preserved overall. These observations may explain why several vaccines have retained the ability to protect against severe COVID-19 even with substantial loss of neutralizing antibody activity against Beta.
    MeSH term(s) Antibodies, Viral ; COVID-19 ; Epitopes ; Humans ; SARS-CoV-2 ; Spike Glycoprotein, Coronavirus/genetics
    Chemical Substances Antibodies, Viral ; Epitopes ; Spike Glycoprotein, Coronavirus
    Language English
    Publishing date 2022-02-09
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2518854-9
    ISSN 1946-6242 ; 1946-6234
    ISSN (online) 1946-6242
    ISSN 1946-6234
    DOI 10.1126/scitranslmed.abj6824
    Database MEDical Literature Analysis and Retrieval System OnLINE

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