Antibody response to SARS-CoV-2 infection over six months among Nicaraguan outpatients

  1. Fredman González
  2. Omar Zepeda
  3. Christian Toval-Ruiz
  4. Armando Matute
  5. Hernan Vanegas
  6. Nancy Munguia
  7. Edwing Centeno
  8. Yaoska Reyes
  9. Lennart Svensson
  10. Johan Nordgren
  11. Aravinda M. de Silva
  12. Sylvia Becker-Dreps
  13. Lakshmanane Premkumar
  14. Filemón Bucardo

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

New information is emerging about SARS-CoV-2 epidemiology and immunity, but little of this information comes from low- and middle-income countries or from patients receiving care in the outpatient setting. The current study investigated the SARS-CoV-2 infection status and antibody responses in 157 patients seeking care for a respiratory disease suggestive of COVID-19 in private healthcare clinics during the first wave (June–October 2020) of infections in Nicaragua. We examined nasal swabs for the presence of viral RNA via RT-PCR and longitudinally collected sera for the changes in SARS-CoV-2 Spike antibody levels over six months. Among patients with confirmed SARS-CoV-2 infections, we evaluated if clinical symptoms were associated with age, hematological parameters and co-morbidities. The combination of PCR and paired serology identified 60 (38%) of the 157 outpatients as acute COVID-19. While both PCR and serology identified the majority (n = 38, 64%) of the acute infections, a notable number of outpatients were identified by RT-qPCR (n = 13, 22%) or by serology (n = 9, 14%) only. During the longitudinal study, we identified 6 new infections by serology among the 97 non-COVID-19 subjects. In conclusion, this study report that more than one third of the outpatients seeking care for acute respiratory disease during the first epidemic wave of SARS-CoV-2 in Nicaragua had an acute mild COVID-19 infection that correlate with prolonged humoral response. This immune response to the RBD antigen, more likely IgG dependent, significantly increased between the acute to convalescent and decay in the late convalescent but still remained seropositive.

Article activity feed

  1. ScreenIT

    SciScore for 10.1101/2021.04.28.21256122: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsConsent: Interested patients were visited in their household by the study team within 17 days PSO to obtain informed consent and collect clinical and demographic data in a questionnaire.
    IACUC: This study was approved by the ethical committee for biomedical research from UNAN-León, on May 2020 and amended in September 2020 (FWA00004523/IRB00003342).
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    In brief, anti-RBD specific immunoglobulins (Ig) and IgM antibodies (ab) were determined by ELISA using heat inactivated serum at 56°C for 30 minutes.
    anti-RBD
    suggested: None
    IgM
    suggested: None
    After washing (TBS-tween-tween 0.2% v/v), 50 µl of goat anti-human alkaline phosphatase conjugated antibody mixture at 1:2500 dilution was added for 1 hr at 37°C 1.
    anti-human alkaline phosphatase
    suggested: None
    All acute, convalescent and late convalescent serum samples were analyzed for IgG, IgA and IgM separately using isotype specific goat anti-human antibody by following the same procedure used for Pan-Ig.
    anti-human
    suggested: None
    Software and Algorithms
    SentencesResources
    All statistical analysis was performed in Statistical Package for the Social Sciences (SPSS version 21).
    Statistical Package for the Social Sciences
    suggested: (SPSS, RRID:SCR_002865)
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2021.04.28.21256122v1 on medRxiv