UNS – Since the Covid-19 pandemic was determined by the WHO (11/3/2020), there were debates between the economics study and medical science. Therefore, the government of Indonesia has decided not to implement a lockdown policy due to several considerations. The biggest consideration is the economic factor because when a lockdown is implemented the economic stability will be affected and economic growth will be slowed or even stopped.
This is different from the hope of medical teams, who concerned if the lockdown policy is not taken then the number of patients infected by Covid-19 will be greater. Moreover, the limited number of medical facilities there will be a deterioration in medical service quality due to the huge number of patients. Those two debates were delivered to open an online lecture by Dr. Sutanto from the Mathematics Study Program, Faculty of Mathematics and Natural Science (FMIPA) UNS on Tuesday, March 24th, 2020.
“Currently the fatality rate of the patients infected by Covid-19 is quite high at 8.4%, or even higher and reach 9% rate. This means that a healthy individual, living in peace suddenly gets infected but they do not know that they are infected with Covid-19. That individual only realizes the disease when it is too late, it is when the symptoms or the pains are severe and they finally passed away,” said Dr. Sutanto.
“When they were got infected and are not aware of the infection, the virus will be transmitted to a healthy person, this is dangerous enough. This means the correlation between the high death rate and the infection rate become really strong,” Dr. Sutanto added.
In the model presented, Dr. Sutanto also explains the dynamic of the Covid-19 population mathematically using the SIQR model. The explanation for the model is Susceptible (S) represents a healthy person who is susceptible to the infection, Infected (I) represent those infected, Quarantine (Q) denotes the quarantine process, and Recovery (R) denotes individual/group that is recovered from Covid-19.
Susceptible is highly affected by contact speed denoted by Beta. If Beta is high due to activities such as meeting, swarming, and collaborative events, thus the potential of a person to get Infected (I) is also high. Further explained, when Infected (I), a fully Quarantine (Q) is implemented, where the scale is depended on each Country’s capability (Alpha). A quarantined person still has two probabilities either Recovered or Dead. Those who are recovered (Recovery), which denoted by “R”, still have the possibility to be susceptible or not susceptible toward a re-infection, which depends on each individual immunity. Therefore, if the individual has good immunity, then the potential to get re-infection (Theta) can be zero.
Based on the SIQR Model (Susceptible-Infected-Quarantine-Recovery) in the form of a differential equation, which solved using the Runge-Kutta Order 4 Numeric Method, it can be concluded that if there is no improvement in the handling, the peak of infection is predicted to take place on the Mid of May 2020. This prediction is made based on the Covid-19 data in Indonesia from 2-22 of March 2020. The prediction is carried out for 100 days of the prediction period (2 March – 10 June 2020).
“If this continues, the peak of infection is in the middle of May, with a total of 2.5 percent of the population in each region (Indonesia population) is infected. During the 100 days prediction, the virus transmission will be reduced in June, but it does not necessarily disappear,” said Dr. Sutanto.
Covid-19 can be eliminated from Indonesia, but it depends on two parameters the Alpha and Beta. The number of Covid-19 infected people could have dropped dramatically, or even disappear if the quarantine speed (Alpha) is greater than the speed of contact from Infected to Susceptible (Beta). There are 3 scenarios that can be done, the first is Quadrant I strategy by increasing quarantine speed and maintain the contact rate at under 0.9, thus the virus will be eliminated before the 10th of June 2020. Second, if Alpha and Beta is located on a slope, thus the virus will be eliminated on June 20th. However, if contact speed is higher than quarantine speed, then the infection will remain in Indonesia.
The government should conduct a rapid test immediately to know the infected individual and a healthy individual. Afterward, the infected cluster should be separated into a referral hospital or the Wisma Atlet in Kamayoran to be isolated. While healthy individuals are under restricted movement order, thus increasing Alpha speed. Next, forcing the health people to stay home to suppress Beta speed.
“If Beta is 0.5 in this simulation, then the virus will be disappeared before 10th June 2020, if not, we are in Quadrant II and this is a very dangerous condition. No need to argue, we have to work and immediately choose Quadrant I this will be faster, the economy will remain good, medical staff will not be exhausted,” Dr. Sutanto ended. Humas UNS