The coronavirus pandemic has forced governments to adopt different approaches to curb its spread, from the most restrictive to the least damaging to the economy, but a study warns that lIsolated measures are not as effective as a combination of these.
This is key because, as long as there is no vaccine, one of the main weapons to combat SARS-CoV-2 is the social distancing, according to research by the University of Edinburgh (Scotland) published this Friday by the magazine The Lancet.
Its model of analysis of measures adopted in 131 countries between January 1 and July 20, 2020 estimated, for example, that the suspension of public events and meetings of more than ten people was translated after 28 days into a 29% reduction from the “R” number, the COVID-19 reproduction rate.
In contrast, by introducing “the most complete package of measures”, similar to a lockdown, the “R” number was reduced by a 52% during the same period.
Between these extremes, the authors designed several scenarios to analyze the impact of other isolated measures – such as the suspension of classes, the closure of workplaces or the limitation of internal displacement – and that of four combinations of restrictions that could be classified as ” bolts “.
“We found that the combination of different measures produced the best results in reducing the transmission of COVID-19. Now that we are experiencing a rebound in the virus, authorities should consider the combination of measures to reduce the ‘R’ number, “study lead author Harish Nair explained in a statement.
His conclusions, he stressed, can help governments decide “what measures can be introduced or eliminated” and “when they will be able to see their effects”, although he recalled that success also depends on the “local context”, that is, the number ” R “there is at that time, of the capacity your health system or socioeconomic impact.
Public events, schools and meetings
Among the most effective isolated measures, the study found that the ban on public events reduced the transmission rate by 24% after 28 days, which can be attributed to the fact that prevents the performance of “supercontagators” and it is often the first decision made by the authorities.
When restrictions are lifted, the return of meetings of more than ten people and the schools reopening were associated with the largest increase in the number “R”, up to 25% and 24%, respectively, followed by the resumption of public events (21%), the end of the limitation of internal displacement (13%) and the withdrawal of the recommendation to stay at home (11%).
It is not clear that the rise in schools, Nair said, can be attributed to “specific age groups”, in which there may be “substantial differences with respect to compliance with social distancing measures inside and outside the classroom”, as well as in class capacity, hygienic habits or mask policy that each country adopts.
“Other studies have shown that certain measures, such as school closings, social distancing and confinement (a combination of all measures) can place the ‘R’ close to or below 1 – indicating that the epidemic is receding. but this is the first work that analyzes the effects of the relaxation of measures about this number, “the authors note.
In this sense, the list of more effective individual measures It is led by the elimination of public events, with a reduction of the “R” of 24% at 28 days, followed by school closings (15%), workplace closures (13%), internal displacement limitation (7 %), and calls to stay home (3%).
Modifications in behavior
For the experts, only the ban on public events, introduced in isolation, it has a “significant statistical impact”, while the softer combination of measures (suspension of public events and meetings of more than ten people) already reduces the “R” by 29%.
The second package of measures (closure of workplaces, prohibition of public events and meetings of more than ten people) caused a fall of 38%, and the third, which adds to these the travel limitation interns, went up to 42%.
The harder combination, which includes all the individual measures cited, reduced the “R” number by one 52%.
The improvements, they add, they are not immediate, Thus, on average, up to eight days must pass from the introduction of the measures to detect a reduction in the rate of 60% of the total. Nor are the increases in the “R” immediate, which, on average, take 17 days to reach 60% of the final figure.
This may be due to the fact that, unlike going back to the classroom – in which life change is instantaneous -, the opening of mobility requires modifications in the behavior of the population, especially after a long period of confinement.