Effectiveness of the ChAdOx1 nCoV-19 Coronavirus Vaccine (CovishieldTM) in Preventing SARS-CoV2 Infection, Chennai, Tamil Nadu, India, 2021

  1. Sharan Murali
  2. Manikandanesan Sakthivel
  3. Kamaraj Pattabi
  4. Vettrichelvan Venkatasamy
  5. Jeromie Wesley Vivian Thangaraj
  6. Anita Shete
  7. Alby John Varghese
  8. Jaganathan Arjun
  9. Chethrapilly Purushothaman Girish Kumar
  10. Pragya D Yadav
  11. Rima Sahay
  12. Triparna Majumdar
  13. Manisha Dudhmal
  14. Azhagendran Sivalingam
  15. Sudha Rani Dhanapal
  16. Augustine Durai Samy
  17. Vijayaprabha Radhakrishnan
  18. Murali Mohan Muni Krishnaiah
  19. Suresh Arunachalam
  20. Punita Muni Krishna Gandhi
  21. Elavarasu Govindasamy
  22. Prabhakaran Chinnappan
  23. Dhana Priya Vadhani Sekar
  24. Prakash Marappan
  25. Ezhil Pounraj
  26. Parasuraman Ganeshkumar
  27. Murugesan Jagadeesan
  28. Manish Narnaware
  29. Gagandeep Singh Bedi
  30. Prabhdeep Kaur
  31. Manoj Murhekar

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Abstract

We estimated the effectiveness of two doses of the ChAdOx1 nCoV-19 (Covishield) vaccine against any COVID-19 infection among individuals ≥45 years in Chennai, Tamil Nadu, India. A community-based cohort study was conducted from May to September 2021 in a selected geographic area in Chennai. The estimated sample size was 10,232. We enrolled 69,435 individuals, of which 21,793 were above 45 years. Two-dose coverage of Covishield in the 18+ and 45+ age group was 18% and 31%, respectively. Genomic analysis of 74 out of the 90 aliquots collected from the 303 COVID-19-positive individuals in the 45+ age group showed delta variants and their sub-lineages. The vaccine’s effectiveness against COVID-19 disease in the ≥45 age group was 61.3% (95% CI: 43.6–73.4) at least 2 weeks after receiving the second dose of Covishield. We demonstrated the effectiveness of two doses of the ChAdOx1 vaccine against the delta variant in the general population of Chennai. We recommend similar future studies considering emerging variants and newer vaccines. Two-dose vaccine coverage could be ensured to protect against COVID-19 infection.

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  1. Version published to 10.3390/vaccines10060970
  2. ScreenIT

    SciScore for 10.1101/2022.04.15.22273859: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: Inclusion Criteria: We included all individuals who gave consent in the study area.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power AnalysisSample Size & Sampling Strategy: Given the high transmission of variants of concern, we assumed 70% VE for the sample size calculation (7,16,17).

    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: We detected the following sentences addressing limitations in the study:
    One of the limitations of the present study was the failure to ascertain the previous infection in the cohort using serology. However, the proportion of asymptomatic infection might have been similar in both vaccinated and non-vaccinated groups. The second limitation was an underestimation of symptomatic infections. We tried to overcome this limitation by using active surveillance for symptomatic infections and testing all symptomatic individuals and contacts. We pooled the line list of all COVID-19 positive individuals tested in any of the labs in the city to ensure the completeness and representativeness. However, we might have missed individuals who did not reveal their symptom status and did not get tested. The third limitation was the inadequate sample size to study the VE against severe infections. Our primary objective was to understand the protective effect of COVID-19 vaccines irrespective of the severity of disease in the general population. As the cases started declining after May 2021, the number of hospitalization were inadequate for subgroup analysis. However, there is adequate evidence to support the usefulness of COVID-19 vaccines in preventing severe infection in India. Two hospital-based case-control studies among RT-PCR tested individuals reported around 80% effectiveness of Covishield (14,27). The effectiveness was 92-94% among a cohort of HCWs predominantly vaccinated with Covishield (13).

    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.
    • No funding statement was detected.
    • 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.

  3. Version published to 10.1101/2022.04.15.22273859v1 on medRxiv