Natural immunity against COVID-19 significantly reduces the risk of reinfection: findings from a cohort of sero-survey participants

  1. Bijaya Kumar Mishra
  2. Debdutta Bhattacharya
  3. Jaya Singh Kshatri
  4. Sanghamitra Pati

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Abstract

Conflicting reports on the persistence of antibody levels in individuals recovered from COVID-19 infection, suggest that the immunity against COVID-19 may not be lasting for long. In India, by 30th June, 2021, not less than 30 million people were infected with COVID-19 and 0.39 million people were reported to have lost their life to the disease in India. I the current study we followed up with a subsample of our previous sero-survey participants to assess whether natural immunity against SARS-CoV-2 was associated with a reduced risk of re-infection. We conducted telephonic interview of a total of 3038 participants, out of which 2238 participants responded and 5 participants were found to be not alive, as conveyed by their close relatives. There was a non-response rate of 26.1%. Out of the 2238 participants, 1170 were sero-positive and 1068 were sero-negative for antibody against COVID-19. Our survey found that only 3 individuals in the sero-positive group got infected with COVID-19 whereas 127 individuals reported contracting the infection the sero-negative group. Interestingly, from the 127 sero-negative individuals who later contracted COVID-19 infection, 30 needed hospitalization, out of which 12 were on oxygen therapy, four in ICU and one was on ventilator. At the other hand, from the 3 sero-positives re-infected with COVID-19, one had hospitalization, but didnnot require oxygen support or critical care. These findings reinforce the strong plausibility that development of antibody following natural infection not only protects against re-infection by the virus to a great extent, but also safeguards against progression to severe COVID-19 disease.

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    SciScore for 10.1101/2021.07.19.21260302: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: Consent was obtained prior to their enrollment in the study.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    No key resources detected.

    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

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  2. Version published to 10.1101/2021.07.19.21260302v1 on medRxiv