Saturday, 24 May 2014

MERS-CoV among healthcare workers: no longer identified or the end of a hospital cluster?

Just looking at @maiamajumder's vast array of MERS-related charts on Twitter and had a thought.

She and I and others have been wondering for a while if perhaps the Kingdom of Saudi Arabia's (KSA) Ministry of Health (MOH) reporting has decided to simply no longer identify healthcare workers (HCWs) as such. That would not be the strangest thing to occur with these data, believe me (deaths that have been "previously reported" that actually haven't, people who were discharged from hospital who were previously not described as being hospitalised, and of course, some instances of HCWs in KSA being identified as MERS-CoV positive by their country of origin and not by the KSA MOH). Perhaps not identifying HCWs is a way of attempting to stop pointing to what was a huge problem in infection prevention and control just last month?

But perhaps that is not entirely what is happening. 

Perhaps there is another reason and there may be some precedent to support it; HCW numbers have in fact realistically decreased because they are no longer being infected as often. Why not? Perhaps because April's Jeddah hospital-based MERS-CoV outbreak is under control. Have a look at the chart below. Some things to note afterwards:


Click on image to enlarge
  1. HCW numbers have stopped accumulating so rapidly. That mirrors total MERS-CoV detections of course. See some recent posts on the now receding wave of April's MERS surge here and here.
  2. The precedent I mentioned? When the Al-Ahsa hospital-related outbreak stopped in May 2013, so did the number of HCW positives/week dropped away. 
  3. There have clearly been a bunch of other HCW peaks which may also have been related to hospital-clusters that were not so obviously publicised (I'll have a loo over this some time in the future). Those spikes of HCW infections have narrower bases and higher peaks than does the Jeddah outbreak, so perhaps that can be used as an indication of them being short-lived clusters that were better controlled than Jeddah. Not rocket science I guess and probably stating the obvious to the experts out there.
  4. Infections in HCWs serve, as we already know, as a kind of sentinel system for identifying a spike in overall cases since more severe disease shows its face in hospitals and most likely represents the presence of other cases out in the community. His statement is much more believable now that we ;can look back and know that milder signs and symptoms of disease, or none at all, do not infrequently follow MERS-CoV infection).
I hope that our original hypotheses - that the KSA MOH has quashed identifying HCWs - was wrong. Heading towards Hajj-2014, it would be best to be polishing the very tarnished reputation of of the KSA MOH on matters ;of communication, not further damaging it.