Data and source code at
The source code, data, and images may be freely used without permission. However, the original data for PCR tests and related statistics were compiled by Tokyo Keizai, and their efforts should be acknowledged by citing their data repository
Questions and comments may be addressed to Saji N. Hameed by email (saji'at-mark'

Saliva based PCR tests

Remarks - A tiny sample size, combined with the apparent mild nature of the sickness makes this study a shaky premise for switching the PCR testing policy


  • The Japanese Ministry of Health approved saliva based PCR tests on June 2, on the condition that it be applied within 9 days of the appearance of symptoms. (Article in the Asahi Shimbun)

  • Till this date, people had to be screened for fever exceeding 37.5C for 3 consecutive days. PCR tests on nasal swabs were conducted...

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PCR positives without Testing

PCR positives reported without tests

Data source

The data analyzed here is the PCR data reported for each of the 47 Japanese prefecture, and is taken from

What is reported here?

The data contains some data points where the number of positive PCR counts equal or exceeds the number of PCR tests. Since positive PCR results are always reported along with a test, this disparity needs to be documented and investigated.

  1. In the...

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