R0: How scientists quantify the intensity of an outbreak like coronavirus and its pandemic potential

R0: How scientists quantify the intensity of an outbreak like coronavirus and its pandemic potential:

A number of groups have estimated R0 for this new coronavirus. The Imperial College group has estimated R0 to be somewhere between 1.5 and 3.5. Scientists from the Chinese Academy of Sciences Institute of Automation and the University of Chinese Academy of Sciences have estimated R0 to be much higher, at 4.08.

These differences are not surprising; there’s uncertainty about many of the factors go into estimating R0, such as in estimating the number of cases, especially early on in an outbreak.

Based on these current estimates, projections of the future number of cases of coronavirus are fraught with high levels of uncertainty and will likely be somewhat inaccurate.

The difficulties arise for a number of reasons.

First, the basic properties of this viral pathogen – like the infectious period – are as yet unknown.

Second, researchers don’t know how many mild cases or infections that don’t result in symptoms have been missed by surveillance but nevertheless are spreading the disease.

Third, the majority of people who come down with this new coronavirus do recover, and are likely then immune to coming down with it again. It’s unclear how the changing susceptibility of the population will affect the future spread of infection. This is especially important in Wuhan, the origin of the epidemic.

Finally, and likely the most important reason, no one knows the future impacts of current disease control measures. Epidemiologists’ current estimates of R0 say nothing about how measures such as isolation or quarantine efforts will influence the virus’ future spread.