Insights into the possible shortcomings of strategies to suppress the spread of the new coronavirus based on only mass PCR testing

Professor Katsutoshi Yada of Kansai University’s Faculty of Commerce and a member of the University’s crisis management analysis task force analyzed the spread of infection due to the new coronavirus infection using a consumer behavior model.

"Our results demonstrate the importance of maintaining a balance between efficient implementation of PCR tests and improving the medical system," says Yada. "Our consumer behavior-based modelling showed that unconditional increases in PCR testing is not an effective way of preventing the spread of infections resulting from the new coronavirus."

The three main findings of this study.

• Developing a model to explicitly account for the quarantine of infected persons by extending conventional SIR (Susceptible-Infected-Recovered) models that are widely used to analyze the transmission of infectious diseases.
• Expansion of PCR tests is predicted to be an effective strategy in the early stages of outbreaks, but reliable quarantine is important later.
• Importance of attaining a balance between efficient implementation of PCR testing, reliable quarantine of infected persons, and enhancement of the medical system.

The role of PCR testing for containing the spread of the new coronavirus

Many commentators propose the expansion of PCR testing as an effective means of preventing the spread of new coronaviruses. But PCR tests alone will not cure infected people, neither will they prevent the spread of COVID-19 to uninfected people. Instead, mitigating the spread of the disease requires not only increasing the number of PCR tests, but also intervention by effective isolation of infected individuals.

Expansion of unconditional PCR tests may have negative effects

Typical infection models used for analyzing the transmission of infectious diseases assume that all infected individuals will be isolated and such models try to estimate the level of seriously ill patients or the risk of death. However, in reality, it is extremely difficult to carry out unlimited numbers of PCR tests and to isolate all infected people.

In a new approach to modeling the spread of infectious diseases, Yada and his team explicitly incorporated changes in the number of quarantined people into their consumer behavior-based model. "It is important to keep track of changes in the number of people who are quarantined and the resulting load on the medical system," explains Yada. "Our model can be used to predict how the degree of quarantine affects epidemics."

Yada and his colleagues found that increasing the quarantine rate was an important factor in suppressing the spread of infection. Furthermore, their analysis showed that expansion of unconditional PCR testing would lead to a rapid increase in the load on medical facilities, that would consequently lead to higher mortality.

"It is necessary to take a scientific approach to combat this epidemic based on data and accurate theoretical models," says Yada. "We are planning to compile policy recommendations to prepare for the possibility of second wave of infections."

Further information

Professor Katsutoshi Yada Kansai University Homepage

https://www2.itc.kansai-u.ac.jp/~yada/hp/en/index.html

Kansai University e-Bulletin, Vol. 13, 7 October 2019

Katsutoshi Yada, Professor, Department of Business and Commerce, Kansai University. "Kansai University research: Kansai University researcher is awarded prestigious prize for the development and advancement of open source data mining technology for business and product marketing"
http://www.kansai-u.ac.jp/Kokusai/e-bulletin/archive/13.php

Research Institute for Socionetwork Strategies, Kansai University

Masao Nakanishi, Is the PCR Test a Panacea for COVID-19? (In Japanese)
RISS Discussion Paper Series No.87 June, 2020.
http://www.kansai-u.ac.jp/riss/research/paper/paper_list.html

PDF of article (In Japanese)
http://www.kansai-u.ac.jp/riss/research/publications/public_files/riss_dp/RISS_DP_No87.pdf