Just two weeks of social distancing policies cut the spread of coronavirus by 65% globally, preventing more than 1.5 million new cases, Texas researchers estimated Thursday.
The few states and countries that resisted social distancing saw almost no reduction in spread, the team at the University of Texas MD Anderson Cancer Center said.
“We found that states observed significant reductions in transmission rates following the implementation of social distancing policies, compared to states without such policies,” Daniel McGrail, a postdoctoral fellow studying systems biology, said in a statement. “In fact, two of the smallest reductions in spread were seen in states without social distancing policies.”
More details: The team set out to see what happened when states enacted social distancing or lockdown policies at the start of the coronavirus pandemic.
The team compared Nebraska and Idaho, two similar states. Idaho had a social distancing policy, while Nebraska did not.
South Dakota, whose governor also resisted a statewide policy, also saw little to no reduction in cases. Wyoming lacked a social distancing policy and the sparsely populated state came in fifteenth from the bottom out of 50 states in terms of reducing coronavirus spread.
But the study was lacking in data, the researchers said.
“While analysis of US states indicated that social distancing policies reduced Covid-19 spread rates proportional to associated reductions in mobility, only having three states without social distancing policies reduces the power of any observation,” they wrote. "To address this, we next expanded our model to the global level.”
They looked at data from 134 different countries.
"Globally, we find that social distancing policies significantly reduced the Covid-19 spread rate, with resulting in an estimated 65% reduction in new Covid-19 cases over a two week time period,” the researchers wrote.
In 46 countries, the policies had a strong effect, preventing an estimated 1.57 million cases of Covid-19 over a two-week period. That represents a 65% reduction in new cases, they said.
Social distancing is not necessarily the only way to reduce spread, they noted.
“For instance, South Korea has not enacted a social distancing program but instead utilized a powerful contact tracing approach to control the spread of Covid-19,” they wrote.