Rahul, Qixin, and Mercedes’ new paper on the transmission dynamics of COVID-19 during the initial invasion in New York City from March-June 2020 was recently published in the Proceedings of the National Academy of Sciences.

Using a mathematical model which was fit to observed case data and serology and took into account daily changes in RT-PCR testing capacity, they were able to precisely estimate the fraction of COVID-19 cases that became symptomatic.

They found that between about 1 in 5 and 1 in 7 COVID-19 cases were symptomatic, and that non-symptomatic cases (this includes both pre-symptomatic and asymptomatic cases together) contributed to at least 50% of the force of infection.

The full published study can be found on the PNAS website.

The article was covered in a press release from the University of Chicago Medicine. An interview summarizing the key findings and implications can be found here .