Tuesday, 18 March 2014

MERS-CoV: sex, age and accumulating death

A few more charts, just to fill out the set for today's Middle East respiratory syndrome coronavirus (MERS-CoV) update.

First Chart.
Click on chart to enlarge.
The first chart shows what everyone knows; MERS, as it has been for the past 2-years, is a severe disease principally of the people of the Kingdom of Saudi Arabia (KSA). 

The route of human acquisition of MERS-CoV remains unknown and will not soon be discovered judging by the lack of any evident plan in the most recent Editorial on MERS-CoV from the KSA's lead author, Prof Ziad Memish. An even less addressed topic is why this disease has such an impact in this particular country given that neighbouring States share aspects of lifestyle, belief and habit.

Second chart.
Click on chart to enlarge.
The second chart reinforces that MERS, in the severe form we see in hospitals, is principally a disease of men (66% of all case are male;  77% among the fatal cases) aged 50 and above (median age is currently 53-years). Something this chart does not show is the that MERS-CoV is a particularly opportunistic virus causing serious disease and death particularly among those who present with an underlying disease (at least a third of cases have a comorbidity of some sort).

Third chart.
Click on chart to enlarge.
In the third chart we can see the human cases by month. Nothing to add for 2012 or 2013 but that steady climb in 2014 should be watched. Why is it there? Why, 2.04 years since we learned of MERS-CoV thanks to the endeavours of an Egyptian scientist named Dr Ali Zaki, are there no public conversations on what is/could/should be done to staunch the trickle of new infections and deaths? Will we see a take-off of cases in April 2014 as we did in 2013? What is happening in Riyadh (where most cases have been of late)? I've added in the Janadriyah festival too because why not?

And in the fourth chart we can see that trickle of new cases but they have thankfully not (yet) been matched by an equivalent rise in fatalities judging by the proportion of fatal cases (PFC) which has dropped a little. The PFC still sits at the "killer virus" level of 42% of all laboratory confirmed cases dying. Not my phrase. 

To generalise, MERS-CoV infection is mainly a cause for serious concern among a particular adult population within the KSA. 

A question I'd like to see answered by studies from the KSA is what is the epidemiology and clinical spectrum of human coronaviruses 229E, NL63, HKU1 and NL63? I believe that would be an interesting study yielding results  that may well put MERS-CoV in a very different context.

Yet another reason for every State to test its population for respiratory viruses I suppose, because then one has a baseline for the known viruses which can help judge the impact of newly identified or emerging viruses.