COVID-19 spread would have been 35 times greater without 4 social distancing measures.
A new study, published in Health Affairs, evaluates whether government restrictions designed to encourage social distancing in the U.S. reduced the spread of the coronavirus, compared to simply providing information and recommendations.
Researchers from the University of Kentucky, University of Louisville, and Georgia State University looked at confirmed COVID-19 cases in the United States between March 1 and April 27. They focused on 4 main government-imposed interventions:
- Shelter-in-place orders (SIPO).
- Public school closures.
- Bans on large social gatherings
- Closures of entertainment-related businesses.
Confirmed COVID-19 cases grew from 30 on March 1 to 978,047 on April 27. On March 1, no jurisdiction had implemented all 4 measures. By April 7, 95% of the U.S. population was covered by all the measures.
Researchers found that adoption of government-imposed social distancing measures reduced the daily COVID-19 case rate by:
- 4 percentage points after 1–5 days.
- 8 percentage points after 6–10 days.
- 2 percentage points after 11–15 days.
- 1 percentage points after 16–20 days.
“Holding the amount of voluntary social distancing constant, these results imply 10 times greater spread by April 27 without SIPOs (10 million cases) and more than 35 times greater spread without any of the 4 measures (35 million),” they wrote.
While closing restaurant dining rooms, bars, and gyms led to statistically significant reductions in the growth rate of COVID-19 cases, there was no evidence that bans on large social gatherings or school closures influenced the growth rate.