  Background: Without proven effect treatments and vaccines, Social Distancing
is the key protection factor against COVID-19. Social distancing alone should
have been enough to protect again the virus, yet things have gone very
differently, with a big mismatch between theory and practice. What are the
reasons? A big problem is that there is no actual social distancing data, and
the corresponding people behavior in a pandemic is unknown. We collect the
world-first dataset on social distancing during the COVID-19 outbreak, so to
see for the first time how people really implement social distancing, identify
dangers of the current situation, and find solutions against this and future
pandemics.
  Methods: Using a sensor-based social distancing belt we collected social
distance data from people in Italy for over two months during the most critical
COVID-19 outbreak. Additionally, we investigated if and how wearing various
Personal Protection Equipment, like masks, influences social distancing.
  Results: Without masks, people adopt a counter-intuitively dangerous
strategy, a paradox that could explain the relative lack of effectiveness of
social distancing. Using masks radically changes the situation, breaking the
paradoxical behavior and leading to a safe social distance behavior. In
shortage of masks, DIY (Do It Yourself) masks can also be used: even without
filtering protection, they provide social distancing protection. Goggles should
be recommended for general use, as they give an extra powerful safety boost.
Generic Public Health policies and media campaigns do not work well on social
distancing: explicit focus on the behavioral problems of necessary mobility are
needed.
