Social distancing outperforms closing borders in preventing virus spread

Editor’s Note

Social distancing was more effective than closing borders in preventing the spread of COVID-19, according to a study published in Cell December 14.

Conducted by Scripps Research, the study examined the efficacy of various mandates—including stay-at-home measures, social distancing, and travel restrictions— in preventing local and regional transmission during the pandemic. Conclusions were based on sequencing more than 82,000 SARS-CoV-2 samples from San Diego and Baja, California, and Mexico and comparing them to SARS-CoV-2 genomes from both North America and worldwide. They combined this genomic data with air and land travel data (using anonymous cell phone tracking) in order to estimate the connectivity of different counties within North America.

Findings indicate that movement between locations drove local transmission rates, not geographic proximity. The findings also showed that the partial closure of the U.S.-Mexico border did not prevent cross-border transmission. Overall, the study indicated that social distancing is the best preventative measure against virus transmission.