  The spread of COVID-19 caused by the recently discovered SARS-CoV-2 virus has
become a worldwide problem with devastating consequences. To slow down the
spread of the pandemic, mass quarantines have been implemented globally,
provoking further social and economic disruptions. Here, we implement a
comprehensive contact tracing network analysis to find an optimized quarantine
protocol to dismantle the chain of transmission of coronavirus with minimal
disruptions to society. We track billions of anonymized GPS human mobility
datapoints from a compilation of hundreds of mobile apps deployed in Latin
America to monitor the evolution of the contact network of disease transmission
before and after the confinements. As a consequence of the lockdowns, people's
mobility across the region decreases by $\sim$53\%, which results in a drastic
disintegration of the transmission network by $\sim$90\%. However, this
disintegration did not halt the spreading of the disease. Our analysis
indicates that superspreading k-core structures persist in the transmission
network to prolong the pandemic. Once the k-cores are identified, an optimized
strategy to break the chain of transmission is to quarantine a minimal number
of 'weak links' with high betweenness centrality connecting the large k-cores.
As countries built contact tracing apps to fight the pandemic, our results
could turn into a valuable resource to help deploy quarantine protocols with
minimized disruptions.
