As I’ve been investigating MERS, I’ve noticed that the mortality rate associated with the disease has seemed to drop off recently. To test whether this was actually the case, I made three graphs. In the first, I plotted all cases of MERS since it was first documented in 2012 to present day; I also included deaths over that same time period:
In this time frame, the mortality is a little over a quarter. However, upon creating this chart, it looked to me as if the mortality associated with this past month was significantly less than its been in the past. So, I decided to take the current outbreak – which began somewhere between the end of March 2014 and beginning of April 2014 – out of the time series:
Apparently, prior to April 2014, the mortality rate associated with MERS was a whopping 39%. To bring the total rate from March 2012 to present all the way down to 27%, I suspected that mortality since the onset of the current outbreak has likely been quite low. With that in mind, I looked at daily case and death incidence since March 20, 2014 to present day:
The mortality associated with MERS since the beginning of this current outbreak is 14%! Now, as I’ve stressed before, data are incomplete. It’s possible that this number will rise if cases that have occurred recently end in death sometime in the future. However, this is a very important distinction to make between MERS today and MERS in the past. If nothing else, it makes MERS a little less terrifying. It’s unclear what factors might be contributing to reduced mortality – despite increased incidence. Perhaps the virus is more transmissible now – but also less virulent… Or maybe we’re just better at treating it now that it’s been a few years since it was first documented. Once we have better access to clinical as well as genomic data, we can attempt to explore these hypotheses. For the time being, we’ll have to do with speculation!
Note: Temporal data indicates date of onset, hospitalization, diagnosis, or public reporting.
Data Sources: KSA MoH & WHO