Lately, one of the questions I’ve been asked is how I see the novel coronavirus outbreak ending. It is a complicated question that is hard to answer. One outcome that I think is worth exploring, as a thought experiment, is that the novel coronavirus outbreak ends with the virus become one of the coronaviruses we deal with perennially (i.e. it becomes endemic as a human viral respiratory virus). The trajectory of the virus has demonstrated its capacity for sustained human-to-human spread at a rate higher than SARS. As such, I believe this virus is spreading akin to a community-acquired coronavirus such as OC43, 229E, HKU1, or NL63. With those coronaviruses, a winter/spring seasonality is present. Thus, I wonder if this virus — absent control efforts currently underway that may dampen the seasonality or smooth it— would exhibit this type of seasonality. It has clearly no need, currently, for whatever animal reservoir(s) it jumped to humans from.
It is hard to completely understand severity yet as very limited data is available but it is evident from observing case counts and death counts that this virus has at maximum an intermediate coronavirus fatality rate. That is, it lies between the community acquired coronaviruses and below SARS. I have seen some estimate it’s fatality rate to be 1/50th of that of MERS. It does appear, from early case studies, that deaths cluster in older adults with comorbidities.
The WHO today stated that they believe control measures are still thought capable of halting transmission and perhaps these efforts will be aided by the natural coronavirus seasonality. However, if transmission isn’t entirely stamped out and low-level transmission continues it could be the case that next winter the novel coronavirus appears again as part of the viral respiratory virus cast. If that happens could it be we will just have another sometimes severe respiratory virus to contend with (of course containment should be the goal so long as it is possible). We have examples of these potentially perilous infections in adenovirus 14, adenovirus 7, the AFM-induced EV-D68, and several others. These viruses are hazards to be dealt with seasonally and are challenging with high burdens of illness in some individuals. Another important example is that of the 2009 H1N1 influenza A strain that emerged in the spring of 2009 and displaced the prior H1N1 strain to transition from a novel pandemic strain to an endemic seasonal strain.
I don’t know how the emergency phase of this outbreak will end or how quickly events will either support or reject this idea I proposed but I think there is more than a zero probability that a 5th community-acquired coronavirus has appeared.