Oscillating spatiotemporal patterns of COVID-19 in the United States.

COVID-19 case rates in the US wax and wane in wave-like patterns over time, but the spatial patterns of these temporal epidemic waves have not been well characterized. By analyzing state- and county-level COVID-19 case rate data for spatiotemporal decomposition modes and oscillatory patterns, we demonstrate that the transmission dynamics of COVID-19 feature recurrent spatiotemporal patterns. In addition to the well-recognized national-level annual mid-winter surges, we demonstrate a prominent but previously unrecognized six-month north-south oscillation in the eastern US (Eastern US COVID-19 Oscillator-EUCO) that gives rise to regional sub-epidemics and travelling epidemic waves. We also demonstrate a second less prominent pattern that oscillates east-west in the northern US (Northern US COVID-19 Oscillator-NUCO). The drivers of these newly recognized oscillatory epidemic patterns remain to be elucidated.