High failure rate of ChAdOx1-nCoV19 immunization against asymptomatic infection in healthcare workers during a Delta variant surge

  1. Rajat Ujjainiya
  2. Akansha Tyagi
  3. Viren Sardana
  4. Salwa Naushin
  5. Nitin Bhatheja
  6. Kartik Kumar
  7. Joydeb Barman
  8. Satyartha Prakash
  9. Rintu Kutum
  10. Akash Kumar Bhaskar
  11. Prateek Singh
  12. Kumardeep Chaudhary
  13. Menka Loomba
  14. Yukti Khanna
  15. Chestha Walecha
  16. Rizwan Ahmed
  17. Ashutosh Yadav
  18. Archana Bajaj
  19. Gaurav Malik
  20. Sahar Qureshi
  21. Swati Waghdhare
  22. Samreen Siddiqui
  23. Kamal Krishan Trehan
  24. Manju Mani
  25. Rajiv Dang
  26. Poonam Das
  27. Pankaj Dougall
  28. Monica Mahajan
  29. Sudipta Sonar
  30. Kamini Jakhar
  31. Reema Kumar
  32. Mahima Tiwari
  33. Shailendra Mani
  34. Sankar Bhattacharyya
  35. Sandeep Budhiraja
  36. Anurag Agrawal
  37. Debasis Dash
  38. Sujeet Jha
  39. Shantanu Sengupta

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Abstract

Immunization is expected to confer protection against infection and severe disease for vaccines while reducing risks to unimmunized populations by inhibiting transmission. Here, based on serial serological studies of an observational cohort of healthcare workers, we show that during a Severe Acute Respiratory Syndrome -Coronavirus 2 Delta-variant outbreak in Delhi, 25.3% (95% Confidence Interval 16.9-35.2) of previously uninfected, ChAdOx1-nCoV19 double vaccinated, healthcare workers were infected within less than two months, based on serology. Induction of anti-spike response was similar between groups with breakthrough infection (541 U/ml, Inter Quartile Range 374) and without (342 U/ml, Inter Quartile Range 497), as was the induction of neutralization activity to wildtype. This was not vaccine failure since vaccine effectiveness estimate based on infection rates in an unvaccinated cohort were about 70% and most infections were asymptomatic. We find that while ChAdOx1-nCoV19 vaccination remains effective in preventing severe infections, it is unlikely to be completely able to block transmission and provide herd immunity.

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  1. Version published to 10.1038/s41467-022-29404-3
  2. Version published to 10.1101/2021.02.28.21252621v5 on medRxiv
  3. Version published to 10.1101/2021.02.28.21252621v4 on medRxiv
  4. Version published to 10.1101/2021.02.28.21252621v3 on medRxiv
  5. Version published to 10.1101/2021.02.28.21252621v2 on medRxiv
  6. ScreenIT

    SciScore for 10.1101/2021.02.28.21252621: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: The study was approved by the ethics committee of Max Hospital, New Delhi and CSIR-IGIB, New Delhi.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical analysis was carried out with visualization in R version 3.6.1 and MS-Excel 2016 and OriginPro V2021.
    OriginPro
    suggested: None

    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.

    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.

  7. Version published to 10.1101/2021.02.28.21252621v1 on medRxiv