- Once a region reaches 25 total COVID deaths, within a month the growth rate in deaths per day falls to approximately zero. In other words, no matter the country or state and its policies, deaths per day stop increasing within 20-30 days of passing a threshold of 25 deaths.
- Once that happens, deaths per day either begin to fall or the trend remains flat.
- The variability in death trends across regions has fallen sharply since the beginning of the epidemic and remains low. All states studied, all countries studied, have become more similar in their trends and have remained so.
- Observations 1-3 suggest that the effective reproduction number, R, has hovered around one worldwide after the first 30 days of the epidemic.
The paper’s conclusion is that the data trends observed above likely indicate that nonpharmaceutical interventions (NPIs) – such as lockdowns, closures, travel restrictions, stay-home orders, event bans, quarantines, curfews, and mask mandates – do not seem to affect virus transmission rates overall.
Why? Because those policies have varied in their timing and implementation across countries and states, but the trends in outcomes do not.