Many countries are taking mobility restriction measures for their respective citizens in the face of the spread of the coronavirus. With the idea of the famous concept of ‘stopping the curve’, the intention of governments, following the recommendations of the WHO, is to minimize the impact of infections on health systems.
But perhaps the mobility constraints have come too late. And this idea could be more than just intuition.
An analysis of human mobility, combining epidemiological data, shows that human mobility was predictive of the epidemic spread in China . Even in the eastern country, which today is an example because it has managed to stabilize the number of infections by SARS-CoV-2, the travel restrictions from Wuhan (the focus of the contagion) came too late.
How do we know this?
The analysis shows how the impact of travel restrictions diminishes as the epidemic progresses. In other words, the movement limitation measures would stop working as the pandemic progresses. Only in the initial stage of the epidemic outbreak would movement restrictions make a truly remarkable effect in containing the coronavirus.
According to the data, provinces outside of Hubei that acted early to test, track and contain COVID-19 cases performed best in preventing or containing local outbreaks. Local person-to-person transmission occurred widely early in the coronavirus outbreak and was mitigated by drastic control measures. However, with an average incubation period of five days (up to 14, in some cases), these mobility restrictions didn’t start to positively impact until over a week later – things started to get worse between the first five to seven days later. local isolation, which took place on January 31.
To be more illustrative: among the cases reported outside of Hubei, 515 had a known travel history to Wuhan and a symptom onset date before January 31, 2020. In contrast, only 39 cases reported symptoms after January 31. January. The spread was already underway.
The research has been conducted by a team from the Oxford Martin Program on Pandemic Genomics and the Department of Zoology at the University of Oxford, using mobile geolocation data from Baidu combined with a rich epidemiological dataset from the Open COVID Data Working Group. -19. Study co-author Dr. Moritz Kraeme explains in a press release:
“Our findings show that, early in the coronavirus outbreak, travel restrictions were effective in preventing the importation of infections from a known source. However, once COVID-19 cases began to spread locally, the contribution of the new cases was far fewer than the cases that had already been imported . At that time, a full set of measures – including local mobility restrictions, testing, tracking and isolation – should have worked together to mitigate the epidemic.
Professor Samuel V. Scarpino of the Network Science Institute (NetSI) at Northeastern University adds: “Political will in many countries lags behind the spread of COVID-19. Travel and mobility restrictions are most helpful since the beginning, when local transmission has not yet become a factor. Once transmission is established, physical distancing and quarantine of sick people will work, but it takes time. “
And now that?
That is the question that many ask. It is of little or no use to complain about the measures that should have been applied “a past bull. This study does not mean that current isolation measures do not serve to reduce infections, but only that those measures would have prevented many more infections weeks earlier.
What governments can do is listen to the experts so that, once the isolation period is over, how to consider returning to normality as safely as possible, to avoid the reintroduction of the coronavirus. As Dr. Moritz Kraeme adds: “Chinese provinces and other countries that have successfully halted internal transmission of COVID-19 should carefully consider how they will re-establish travel and mobility to avoid reintroduction and spread of the disease in their populations. “.
Reference:
Moritz UG Kraemer. The effect of human mobility and control measures on the COVID-19 epidemic in China (25 Mar 2020) Science DOI: 10.1126 / science.abb4218
