Encouraging signs from nationwide drop in transmission rate

We begin the month with encouraging news: the rate of illness transmission (Rt) is relatively stable at around 1 in many states, and as a result, there are no states on our watch list this week.

For example, the recent Rt trend has improved in Nebraska, a state that was on our watch list in mid-August due to a sustained elevation in illness transmission. Nebraska has indeed experienced a steep increase in daily confirmed COVID-19 cases since then – setting a new record for weekly cases in early September – but a slowdown in Rt in the past week suggests that this upward trend in cases may soon slow.

There are some regions with modestly elevated illness transmission – Southern California, for example – but no states are showing alarmingly high rates of illness spread. At a national level, Rt has leveled off around 1 for the past few weeks, suggesting that we will not see major changes in case numbers in the coming weeks.


While this may sound promising, as it suggests that cases will not increase significantly, it also suggests that the recent downward trend in new cases will slow or plateau. Our current case volume – roughly 40,000 new cases per day – is still higher than the initial April peak, and represents a concerning baseline as we move into flu season. We clearly need to do more to help curb the spread of COVID-19. It bears repeating that we’ve seen clear declines in illness transmission following the implementation of mask requirements and social distancing measures. As we head into the start of the school year, we must keep our guard up and remain committed to the protective measures that paved the way for this recent progress.