By Jonathan Springston, Editor, Relias Media

By taking emergency health measures, researchers estimate six countries prevented more than 500 million COVID-19 infections between early January and early April.

Investigators examined more than 1,700 local, regional, and national policies implemented in the United States, China, France, Iran, Italy, and South Korea from January through April 6. These included travel restrictions, shelter-in-place orders, school and business closures, and other nonpharmaceutical techniques.

The authors estimated these measures prevented 530 million COVID-19 infections, 62 million of which could have become confirmed cases. For the United States specifically, the authors estimated emergency health measures prevented about 4.8 million confirmed cases and 60 million total cases.

“The last several months have been extraordinarily difficult, but through our individual sacrifices, people everywhere have each contributed to one of humanity’s greatest collective achievements,” lead author Solomon Hsiang, director of UC Berkeley’s Global Policy Laboratory and Chancellor’s Professor at the Goldman School of Public Policy, said in a statement. “I don’t think any human endeavor has ever saved so many lives in such a short period. There have been huge personal costs to staying home and canceling events, but the data show that each day made a profound difference. By using science and cooperating, we changed the course of history.”

Hsiang and colleagues looked at the progression of infections before and after policies were enacted, measuring how different policies contributed to flattening the curve. The team considered local testing policies and studied confirmed cases accordingly. However, to account for limited testing and wide variations in carrying out those tests, the authors calculated what infection rates may have been if everyone had been tested.

“Our results suggest that ongoing anti-contagion policies have already substantially reduced the number of COVID-19 infections observed in the world today,” the researchers wrote. “Based on these results, we find that the deployment of anti-contagion policies in all six countries significantly and substantially slowed the pandemic.”

As of June 11, the Centers for Disease Control and Prevention reports 1,994,283 total COVID-19 cases and 112,967 deaths in the United States.

In the June 15 issue of Internal Medicine Alert, author Seema Gupta, MD, MSPH, wrote about the association of public health interventions with the epidemiological features of the COVID-19 outbreak in Wuhan, China. The authors of a study found nonpharmaceutical interventions, including home confinement, social distancing, centralized quarantine, cordons sanitaire, and traffic restriction, may be associated with better outbreak control.

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