Infectiousness in omicron variant strain and bA.2 variant in Japan

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Abstract

Background

Omicron variant strain dominated since the beginning of 2022. Its infectivity was supposes to be higher than Delta variant strain or strains in past.

Object

We estimated prevalence of omicron variant strain, particularly bA.2 variant and COVID-19 vaccine effectiveness of the third dose in Japan as well as controlling for waning of second dose of vaccine, other mutated strains, the Olympic Games, and countermeasures.

Method

The effective reproduction number R( t ) was regressed on shares of omicron variant strain and bA.2 and vaccine coverage of the third dose, as well as along with data of temperature, humidity, mobility, share of the other mutated strains, and an Olympic Games and countermeasures. The study period was February, 2020 through February 21, 2022, as of March 15, 2022.

Results

Estimation results indicated that waning of the second dose vaccine e with 150 days prior was the most appropriate specification. Moreover, bA.2 of omicron variant strain has higher infectively than other variant strain or traditional strain.

Discussion

Because of data limitation since emerging bA.2, the estimated its infectively will change over time.

Article activity feed

  1. SciScore for 10.1101/2021.06.20.21259209: (What is this?)

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

    Table 1: Rigor

    Ethicsnot detected.
    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: We detected the following sentences addressing limitations in the study:
    The present study has some limitations. First, as described above, effects of vaccine coverage and estimated herd immunity might be overestimated. Accumulation of the data will probably resolve this problem. Secondly, readers must be reminded when interpreting the obtained results that our obtained results do not indicate causality. This study demonstrated that some association exists among vaccine coverage and infectiousness. That finding does not necessarily mean that vaccine coverage reduces infectiousness: it might imply that lower infectiousness, for instance, an effective reproduction number being smaller than one, induces people to approach vaccination more enthusiastically.

    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.