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  1. Article ; Online: The Usefulness of Antigen Testing in Predicting Contagiousness in COVID-19.

    Lopera, Tulio J / Alzate-Ángel, Juan Carlos / Díaz, Francisco J / Rugeles, María T / Aguilar-Jiménez, Wbeimar

    Microbiology spectrum

    2022  Volume 10, Issue 2, Page(s) e0196221

    Abstract: Increasing the diagnostic capacity for COVID-19 (SARS-CoV-2 infection) is required to improve case detection, reduce COVID-19 expansion, and boost the world economy. Rapid antigen detection tests are less expensive and easier to implement, but their ... ...

    Abstract Increasing the diagnostic capacity for COVID-19 (SARS-CoV-2 infection) is required to improve case detection, reduce COVID-19 expansion, and boost the world economy. Rapid antigen detection tests are less expensive and easier to implement, but their diagnostic performance has been questioned compared to reverse transcription-PCR (RT-PCR). Here, we evaluate the performance of the Standard Q COVID-19 antigen test for diagnosing SARS-CoV-2 infection and predicting contagiousness compared to RT-PCR and viral culture, respectively. The antigen test was 100.0% specific but only 40.9% sensitive for diagnosing infection compared to RT-PCR. Interestingly, SARS-CoV-2 contagiousness is highly unlikely with a negative antigen test since it exhibited a negative predictive value of 99.9% compared to viral culture. Furthermore, a cycle threshold (
    MeSH term(s) Antigens, Viral/analysis ; COVID-19/diagnosis ; COVID-19 Serological Testing ; Humans ; SARS-CoV-2/genetics ; Sensitivity and Specificity
    Chemical Substances Antigens, Viral
    Language English
    Publishing date 2022-03-29
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2807133-5
    ISSN 2165-0497 ; 2165-0497
    ISSN (online) 2165-0497
    ISSN 2165-0497
    DOI 10.1128/spectrum.01962-21
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Humoral Response to BNT162b2 Vaccine Against SARS-CoV-2 Variants Decays After Six Months.

    Lopera, Tulio J / Chvatal-Medina, Mateo / Flórez-Álvarez, Lizdany / Zapata-Cardona, Maria I / Taborda, Natalia A / Rugeles, Maria T / Hernandez, Juan C

    Frontiers in immunology

    2022  Volume 13, Page(s) 879036

    Abstract: SARS-CoV-2 vaccines have shown very high effectiveness in real-world scenarios. However, there is compelling evidence for a fast-paced waning of immunity. The increasing number of new variants that could alter the severity, transmissibility, and ... ...

    Abstract SARS-CoV-2 vaccines have shown very high effectiveness in real-world scenarios. However, there is compelling evidence for a fast-paced waning of immunity. The increasing number of new variants that could alter the severity, transmissibility, and potential to evade the immune response raised significant concern. Therefore, elucidating changes in the humoral immune response against viral variants induced by vaccines over time is crucial for improving immunization protocols. We carried out a 6-month longitudinal prospective study in which 60 individuals between 21 and 71 years of age who have received the complete scheme of the BNT162b2 vaccine were followed to determine titers of serum neutralizing activity. The neutralizing capacity was measured at one, three, and six-months post-vaccination by plaque reduction neutralization assay using SARS-CoV-2 B.1 (D614G) and the Gamma, Alpha, Delta, and Mu variants. Data were analyzed using GraphPad 5.0. Neutralizing activity against five different SARS-CoV-2 variants was detected in the serum samples of all vaccinated participants to a different extent after one month, with a progressive decrease according to age and gender. Overall, after one month of vaccination, the neutralizing titer was lower for all evaluated variants when compared to B.1, most remarkable against Delta and Mu, with a reduction of 83.1% and 92.3%, respectively. In addition, the Titer at 3- or 6-months follow-up decreased dramatically for all variants. Our results support the decaying of serum neutralizing activity, both over time and across SARS-CoV-2 variants, being more significant in older men. Since Delta and Mu appear to evade the neutralizing activity, these and further new variants of immune escape mutations should be considered for novel vaccine formulations.
    MeSH term(s) Aged ; Antibodies, Neutralizing ; Antibodies, Viral ; BNT162 Vaccine ; COVID-19/prevention & control ; COVID-19 Vaccines ; Humans ; Male ; Prospective Studies ; SARS-CoV-2
    Chemical Substances Antibodies, Neutralizing ; Antibodies, Viral ; COVID-19 Vaccines ; BNT162 Vaccine (N38TVC63NU)
    Language English
    Publishing date 2022-05-02
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2606827-8
    ISSN 1664-3224 ; 1664-3224
    ISSN (online) 1664-3224
    ISSN 1664-3224
    DOI 10.3389/fimmu.2022.879036
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: The usefulness of antigen testing in predicting contagiousness in COVID-19

    Lopera, Tulio J. / Diaz, Francisco J. / Alzate-Angel, Juan C. / Rugeles, Maria Teresa / Aguilar-Jimenez, Wbeimar

    medRxiv

    Abstract: Increasing the diagnostic capacity of COVID-19 (SARS-CoV-2 infection) is required to improve case detection, reduce COVID-19 expansion, and boost the world economy. Rapid antigen detection tests are cheaper and easier to implement, but their diagnostic ... ...

    Abstract Increasing the diagnostic capacity of COVID-19 (SARS-CoV-2 infection) is required to improve case detection, reduce COVID-19 expansion, and boost the world economy. Rapid antigen detection tests are cheaper and easier to implement, but their diagnostic performance has been questioned compared to RT-PCR. Here, we evaluate the performance of the Standard Q COVID-19 antigen test for diagnosing SARS-CoV-2 infection and predicting contagiousness compared to RT-PCR and viral culture, respectively. The antigen test was 100.0% specific but only 40.9% sensitive for diagnosing infection compared to RT-PCR. Interestingly, SARS-CoV-2 contagiousness is highly unlikely with a negative antigen test since it exhibited a negative predictive value of 99.9% than viral culture. Furthermore, a cycle threshold (Ct) value of 18.1 in RT-PCR was shown to be the one that best predicts contagiousness (AUC 97.6%). Thus, screening people with antigen testing is a good approach to prevent SARS-CoV-2 contagion and allow returning to daily activities.
    Keywords covid19
    Language English
    Publishing date 2021-10-18
    Publisher Cold Spring Harbor Laboratory Press
    Document type Article ; Online
    DOI 10.1101/2021.10.16.21265067
    Database COVID19

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  4. Article ; Online: A specific structure and high richness characterize intestinal microbiota of HIV-exposed seronegative individuals.

    Lopera, Tulio J / Lujan, Jorge A / Zurek, Eduardo / Zapata, Wildeman / Hernandez, Juan C / Toro, Miguel A / Alzate, Juan F / Taborda, Natalia A / Rugeles, Maria T / Aguilar-Jimenez, Wbeimar

    PloS one

    2021  Volume 16, Issue 12, Page(s) e0260729

    Abstract: Intestinal microbiota facilitates food breakdown for energy metabolism and influences the immune response, maintaining mucosal homeostasis. Overall, HIV infection is associated with intestinal dysbiosis and immune activation, which has been related to ... ...

    Abstract Intestinal microbiota facilitates food breakdown for energy metabolism and influences the immune response, maintaining mucosal homeostasis. Overall, HIV infection is associated with intestinal dysbiosis and immune activation, which has been related to seroconversion in HIV-exposed individuals. However, it is unclear whether microbiota dysbiosis is the cause or the effect of immune alterations and disease progression or if it could modulate the risk of acquiring the HIV infection. We characterize the intestinal microbiota and determine its association with immune regulation in HIV-exposed seronegative individuals (HESN), HIV-infected progressors (HIV+), and healthy control (HC) subjects. For this, feces and blood were collected. The microbiota composition of HESN showed a significantly higher alpha (p = 0.040) and beta diversity (p = 0.006) compared to HC, but no differences were found compared to HIV+. A lower Treg percentage was observed in HESN (1.77%) than HC (2.98%) and HIV+ (4.02%), with enrichment of the genus Butyrivibrio (p = 0.029) being characteristic of this profile. Moreover, we found that Megasphaera (p = 0.017) and Victivallis (p = 0.0029) also are enriched in the microbiota composition in HESN compared to HC and HIV+ subjects. Interestingly, an increase in Succinivibrio and Prevotella, and a reduction in Bacteroides genus, which is typical of HIV-infected individuals, were observed in both HESN and HIV+, compared to HC. Thus, HESNs have a microbiota profile, similar to that observed in HIV+, most likely because HESN are cohabiting with their HIV+ partners.
    MeSH term(s) Adolescent ; Adult ; Butyrivibrio/isolation & purification ; Case-Control Studies ; Feces/microbiology ; Female ; Gastrointestinal Microbiome ; HIV Infections/immunology ; HIV Infections/pathology ; HIV Seronegativity ; Humans ; Male ; Megasphaera/isolation & purification ; Middle Aged ; Prevotella/isolation & purification ; T-Lymphocytes, Regulatory/cytology ; T-Lymphocytes, Regulatory/immunology ; T-Lymphocytes, Regulatory/metabolism ; Th17 Cells/cytology ; Th17 Cells/immunology ; Th17 Cells/metabolism ; Young Adult
    Language English
    Publishing date 2021-12-02
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0260729
    Database MEDical Literature Analysis and Retrieval System OnLINE

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