Member-only story
Covid-19 May Take Longer Than 14 Days to Spread
Experts are divided as to why
As Covid-19 spreads worldwide, public health authorities have reconsidered nearly everything about the virus. Changes in policy have addressed everything from basics of how it spreads, to the value of protection measures like face masks. One thing that largely hasn’t changed, though, is guidance on Covid-19’s incubation period and the time course of its spread. Both the Centers for Disease Control and Prevention and the World Health Organization estimate this number at 5–14 days.
Their figures, however, are based on a variety of assumptions — as well as data which is often distressingly thin and biased. New data and empirical observations are beginning to suggest that the time course of Covid-19’s spread, and perhaps the virus' incubation period itself, may be much longer in certain populations and situations— perhaps up to 30 days. If that’s the case, many of the models used to plan reopening, monitor disease progress and coordinate testing could be dangerously wrong.
As the Covid-19 virus began to spread in the United States in early 2020, authorities quickly worked to determine its incubation period. Even today, both the CDC and WHO prominently cite a single study by Laurer et al., originally published near the start of the virus’ spread in March of 2020…
