Alliance for Pandemic Preparedness

July 22, 2020

Serial Interval of SARS-CoV-2 Was Shortened over Time by Nonpharmaceutical Interventions

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  • Analyzing 677 transmission pairs in mainland China, Ali et al. found that the COVID-19 serial interval, which is the time between symptom onset for the infector and the infectee in a linked transmission pair, shortened from 7.8 days to 2.6 days between Jan 9 and Feb 13.  The serial interval was positively associated with the length of time between a person’s symptom onset and their isolation (i.e. isolation delay). The investigators attribute these findings to the adoption of policies for rapid isolation of people with COVID-19 symptoms, and argue that changes in the serial interval indicate effective implementation of transmission reduction interventions.  

Ali et al. (July 21, 2020). Serial Interval of SARS-CoV-2 Was Shortened over Time by Nonpharmaceutical Interventions. Science. https://doi.org/10.1126/science.abc9004