September 26, 2020

control the epidemic with mathematics



Spanish scientists develop a model to predict the extent of the disease

The fight against the coronavirus Covid-19 It is a global effort. In the front line are the doctors who take care of patients every day. Behind are researchers looking for a vaccine and epidemiologists who establish health measures to contain the virus. There is also a third front. You did not wear a white coat but it is essential to stop the spread of the virus. There are mathematicians like the team that works in the Institute of Interdisciplinary Mathematics from the Complutense University of Madrid.

Professor Ángel Manuel Ramos del Olmo is the director of the Institute team and the research group on mathematical models (MOMAT). Your team has made a study to determine the scope and the duration of the coronavirus epidemic.

Ramos began studying the epidemics of swine fever in the community of Madrid. A disease that does not affect the human being but that can have important economic consequences for farmers in the region. The system proved reliable and it was decided to test with the Ebola outbreak of 2014-16. According to the forecast, the epidemic would have ended in March 2016. WHO declared it extinct in early April.

When will the disease peak?

“There are many people who have to make decisions to deal with an epidemic,” explains Ramos. Knowing how many hospital beds will be needed, how many vaccines to produce and when the disease will peak can help in decision making. ”

A model is not a crystal ball. You can provide an approximate and reliable result but you also need certain data. China has changed the criteria with which it is determined if a person is infected or not by Covid-19 and obliged the mathematicians of the Complutense to correct their forecasts.

As of February 13, the Chinese authorities have begun to count as active cases patients presenting clinical signs of the disease without waiting for the confirmation of laboratory tests. From one day to the next the disease has added 14,840 infections and 242 deaths. A 34% increase which has tested the model developed in Madrid.

The fragility of the data

“What we do is look for a range of estimation, not an exact figure,” says Professor Benjamin Ivorra in front of the three computer screens in his office. Ivorra explains that at the end of January MOMAT made a first simulation. The hypothesis of a “Patient X” was raised, the first to contract the virus. To this were added the data provided by WHO on the infection rate, those infected who have not developed symptoms, mortality and Recovery.

The formula elaborated in Madrid allows to calculate the extension and the end of the epidemic. According to the results published on February 9, as of March 1, the rate of infection would have begun to decline coinciding with the cap of people admitted. In July the epidemic would have been under control. China would be the country most affected by both people affected (with a maximum of 80,000 cases) and deaths (4175). In total, Covid-19 could infect between 60,000 and 70,000 people worldwide without reaching five thousand deaths. In Spain the cases would not exceed 5 without causing victims.

WHO has criticized China for having unilaterally changed the diagnostic criteria and only for the province of Hubei, the epicenter of contagion. At a press conference at the WHO headquarters in Geneva, emergency operations chief Mike Ryan has reiterated That is not about new infections. The lack of an increase in cases in the rest of China, Hong Kong and Singapore would indicate that there are no “hidden infections”. An indication that the vid iceberg ’of Covid-19 might not be so big. Even so, the new measurement has forced Madrid’s mathematicians to redo their calculations. We are still in the expected range but the system will have to be recalibrated. A job that will take days or weeks.

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