A new model that predicts the course of the COVID-19 pandemic in Italy, using data from the outbreak in that country, shows that the restrictive social distancing measures adopted are necessary and effective and must be applied quickly at the earliest stage. But he warns that these measures of social distancing should be combined with generalized tests among the population, as did some countries where infection has been controlled, such as Germany, and contact tracing to end the current COVID-19 pandemic. Other countries, such as Italy, Spain or the United Kingdom, did not implement these measures in the first week and their situation is worse.
The information published in « Nature Medicine»Shows that in a less restrictive confinement scenario there would be 70,000 deaths in the first year, while, with stricter measures, the number of deaths per year would be 25,000 deaths.
The report underscores that confinement measures can only be safely relieved in the presence of widespread diagnostic tests and contact tracing.
This data could provide control policy makers in Italy, and in other countries, with a tool to assess the consequences of possible strategies, including confinement and social distancing, as well as testing and monitoring contacts.
Ending the global pandemic of COVID-19 requires the implementation of multiple strategies for the entire population, but the effectiveness of such strategies and their ability to “flatten the curve” remains uncertain.
Giulia Giordano and her colleagues from the University of Trento (Italy) describe in their work a new epidemiological model for the COVID-19 pandemic, called “SIDARTHE“, which distinguishes between detected (diagnosed) and undetected (undiagnosed) cases and between different stages of infection.
Researchers have classified the population based on eight stages of infection: susceptible (uninfected); infected (asymptomatic or with few symptoms, infected, not detected); diagnosed (asymptomatic infected, detected); sick (symptomatic infected, not detected); recognized (symptomatic infected, detected); threatened (infected with life-threatening symptoms, detected); cured (recovered); and extinct (dead).
The authors used data collected in Italy from February 20, 2020 (day 1) to April 5, 2020 (day 46) to show how progressive restrictions, including confinement imposed since March 9, 2020, have affected the spread of the pandemic in Italy.
They also modeled possible longer-term scenarios of the effects of various countermeasures, including social distancing, contact tracing, and testing across the population.
The model predicted that the maximum number of people actually infected simultaneously would occur around day 50, with 0.19% of the infected population; however, the maximum number of people detected with concurrent infection would occur approximately one week later.
The findings confirm the hypothesis that diagnostic testing campaigns among populations can reduce the peak of infection and help control the pandemic faster.
However, the model does not contemplate a precarious situation in medical care due to the fact that the health system does not reach or is even exceeded in its capacity; but the authors point out that these analyzes can be carried out indirectly. For example, when the number of severely affected people is high, the death rate will increase due to an insufficient number of intensive care units (ICUs).
Finally, the authors also found that partial implementation of confinement measures would cause a delay in the peak of simultaneously infected people and patients admitted to the ICU, but with a moderate decrease in the total number of infected people and admission to the ICU.
Conversely, implementing very restrictive social distancing strategies would result in a lower peak of infected people and patients admitted to the ICU, with a marked decrease in the total number of infected people and ICU admissions due to the disease.
The authors estimate that, in the first scenario – a less restrictive closure – there would be 70,000 deaths in the first year, while in the second case – a stricter closure – the number of deaths per year would be 25,000 deaths.
And they conclude that their results demonstrate that restrictive social distancing measures will need to be combined with widespread testing and contact tracing to end the current COVID-19 pandemic.