Pathfinder
Editor, Senior Moderator
Suppression of COVID-19 infection by isolation time control based on the SIR model and an analogy from nuclear fusion research
Osamu Mitarai, Nagato Yanagi
doi: https://doi.org/10.1101/2020.09.18.20197723
Posted September 20, 2020.
This article is a preprint and has not been certified by peer review [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.
Abstract
The coronavirus disease 2019 (COVID-19) has been damaging our daily life after declaration of pandemic. Therefore, we have started studying on the characteristics of Susceptible-Infectious-Recovered (SIR) model to know about the truth of infectious disease and our future.
After detailed studies on the characteristics of the SIR model for the various parameter dependencies with respect to such as the outing restriction (lockdown) ratio and vaccination rate, we have finally noticed that the second term (isolation term) in the differential equation of the number of the infected is quite similar to the "helium ash particle loss term" in deuterium-tritium (D-T) nuclear fusion. Based on this analogy, we have found that isolation of the infected is not actively controlled in the SIR model. Then we introduce the isolation control time parameter q and have studied its effect on this pandemic. Required isolation time to terminate the COVID-19 can be estimated by this proposed method.
To show this isolation control effect, we choose Tokyo for the model calculation because of high population density. We determine the reproduction number and the isolation ratio in the initial uncontrolled phase, and then the future number of the infected is estimated under various conditions. If the confirmed case can be isolated in 3~8 days by widely performed testing, this pandemic could be suppressed without awaiting vaccination. If the mild outing restriction and vaccination are taken together, the isolation control time can be longer. We consider this isolation time control might be the only solution to overcome the pandemic when vaccine is not available.
...
4.Discussions and summary
...
Big problem in this COVID-19 is that there are a lot of asymptomatic but infectious cases (Dickens et al., 2020, Long et al., 2020). Therefore, active and massive testing is so important for quick isolation of the identified person. Such technology has been under active development. For example, recently the new method is invented by TakaraBio in USA to allow faster and larger scale PCR testing, where 5,000 tests can be done in about two hours (TakaraBio 2020). As the National Institute of Health is aiming at the 6 million PCR test per day, such aggressive research plan is promising to suppress this pandemic (Tromberg et al., 2020). Recently, innovative technique such as vocal biomarkars is proposed by MIT Lincoln Laboratory to identify the asymptomatic people with COVID-19 positive (Quatieri et al, 2020). Vocal change before and after infection could be detected by processing speech recording. In addition, contact-tracing technique using communication tool is also useful (Hellewell et al., 2020). Various new ideas from the different research areas should be developed to overcome this pandemic.
To know the truth of infectious disease, we have studied the characteristics of SIR model equation in detail. Based on the He ash removal study in a D-T nuclear fusion (Mitarai and Muraoka,1997), we have found that the time in the isolation term can be interpreted as the natural isolation time, which means that the isolation is not conducted in a controlled manner in a traditional SIR model. Therefore, we introduce the isolation time control parameter q to control the isolation time. We have finally found that the outing restriction ratio c, the vaccination rate v, and the isolation time control parameter q are equivalent with respect to the basic reproduction number. This means that isolation control has the same function of vaccination or the outing restriction. In an actual situation especially after the first wave when the number of patient decreases, massive PCR testing etc should be conducted and then infected people especially without symptom should be identified and isolated as soon as possible. We have to construct such an advanced social system with great care about human rights. Without such system, the economic activity cannot be maintained unless a safe vaccine is not supplied.
In this study, the required isolation time is 3 ~ 5 days without any outing restriction, but it can be longer as 5 ~ 8 days with the outing restriction of c=0.3 to suppress this COVID-19. We note that this value is obtained by the new way of life as shown in Fig.3-(b). Although this isolation time depends on the basic reproduction number, the required isolation time obtained in this study is quite realistic and could be accomplished. Above estimated time could be also justified by the fact that the median duration of viral shedding in the asymptomatic group is 19 days (Long et al., 2020). This value is quite similar to our employed value of infectious period or recovery time τ =17.54 days. This isolation control concept may be able to explain the part of success in South Korea and Taiwan to suppress COVID-19 disease.
In conclusion, with reliable, simple and massive testing method, if isolation can be done in a short time after case identification, this pandemic could be overcome without the strong outing restriction such as lockdown before vaccine is completed. Medical research institutes and pharmaceutical companies are actively developing the vaccine to curtail this pandemic. In contrast, only the central and local governments can do wide, repeated and quick COVID-19 testing and quick isolation. The bureaucratic system such as the public health center and the ministry of health can play an important role to manage the isolation control together with various laws. Upon considering this simple theory proposed here, we believe government should be definitely a main player to terminate this infectious disease.
...
https://www.medrxiv.org/content/10.1101/2020.09.18.20197723v1.full.pdf
https://www.medrxiv.org/node/97519.external-links.html
Osamu Mitarai, Nagato Yanagi
doi: https://doi.org/10.1101/2020.09.18.20197723
Posted September 20, 2020.
This article is a preprint and has not been certified by peer review [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.
Abstract
The coronavirus disease 2019 (COVID-19) has been damaging our daily life after declaration of pandemic. Therefore, we have started studying on the characteristics of Susceptible-Infectious-Recovered (SIR) model to know about the truth of infectious disease and our future.
After detailed studies on the characteristics of the SIR model for the various parameter dependencies with respect to such as the outing restriction (lockdown) ratio and vaccination rate, we have finally noticed that the second term (isolation term) in the differential equation of the number of the infected is quite similar to the "helium ash particle loss term" in deuterium-tritium (D-T) nuclear fusion. Based on this analogy, we have found that isolation of the infected is not actively controlled in the SIR model. Then we introduce the isolation control time parameter q and have studied its effect on this pandemic. Required isolation time to terminate the COVID-19 can be estimated by this proposed method.
To show this isolation control effect, we choose Tokyo for the model calculation because of high population density. We determine the reproduction number and the isolation ratio in the initial uncontrolled phase, and then the future number of the infected is estimated under various conditions. If the confirmed case can be isolated in 3~8 days by widely performed testing, this pandemic could be suppressed without awaiting vaccination. If the mild outing restriction and vaccination are taken together, the isolation control time can be longer. We consider this isolation time control might be the only solution to overcome the pandemic when vaccine is not available.
...
4.Discussions and summary
...
Big problem in this COVID-19 is that there are a lot of asymptomatic but infectious cases (Dickens et al., 2020, Long et al., 2020). Therefore, active and massive testing is so important for quick isolation of the identified person. Such technology has been under active development. For example, recently the new method is invented by TakaraBio in USA to allow faster and larger scale PCR testing, where 5,000 tests can be done in about two hours (TakaraBio 2020). As the National Institute of Health is aiming at the 6 million PCR test per day, such aggressive research plan is promising to suppress this pandemic (Tromberg et al., 2020). Recently, innovative technique such as vocal biomarkars is proposed by MIT Lincoln Laboratory to identify the asymptomatic people with COVID-19 positive (Quatieri et al, 2020). Vocal change before and after infection could be detected by processing speech recording. In addition, contact-tracing technique using communication tool is also useful (Hellewell et al., 2020). Various new ideas from the different research areas should be developed to overcome this pandemic.
To know the truth of infectious disease, we have studied the characteristics of SIR model equation in detail. Based on the He ash removal study in a D-T nuclear fusion (Mitarai and Muraoka,1997), we have found that the time in the isolation term can be interpreted as the natural isolation time, which means that the isolation is not conducted in a controlled manner in a traditional SIR model. Therefore, we introduce the isolation time control parameter q to control the isolation time. We have finally found that the outing restriction ratio c, the vaccination rate v, and the isolation time control parameter q are equivalent with respect to the basic reproduction number. This means that isolation control has the same function of vaccination or the outing restriction. In an actual situation especially after the first wave when the number of patient decreases, massive PCR testing etc should be conducted and then infected people especially without symptom should be identified and isolated as soon as possible. We have to construct such an advanced social system with great care about human rights. Without such system, the economic activity cannot be maintained unless a safe vaccine is not supplied.
In this study, the required isolation time is 3 ~ 5 days without any outing restriction, but it can be longer as 5 ~ 8 days with the outing restriction of c=0.3 to suppress this COVID-19. We note that this value is obtained by the new way of life as shown in Fig.3-(b). Although this isolation time depends on the basic reproduction number, the required isolation time obtained in this study is quite realistic and could be accomplished. Above estimated time could be also justified by the fact that the median duration of viral shedding in the asymptomatic group is 19 days (Long et al., 2020). This value is quite similar to our employed value of infectious period or recovery time τ =17.54 days. This isolation control concept may be able to explain the part of success in South Korea and Taiwan to suppress COVID-19 disease.
In conclusion, with reliable, simple and massive testing method, if isolation can be done in a short time after case identification, this pandemic could be overcome without the strong outing restriction such as lockdown before vaccine is completed. Medical research institutes and pharmaceutical companies are actively developing the vaccine to curtail this pandemic. In contrast, only the central and local governments can do wide, repeated and quick COVID-19 testing and quick isolation. The bureaucratic system such as the public health center and the ministry of health can play an important role to manage the isolation control together with various laws. Upon considering this simple theory proposed here, we believe government should be definitely a main player to terminate this infectious disease.
...
https://www.medrxiv.org/content/10.1101/2020.09.18.20197723v1.full.pdf
https://www.medrxiv.org/node/97519.external-links.html