Sunday, 20 April 2014

MERS-CoV cases and deaths by month and growing tallies: a look at the impact of 2 clusters on a "slowly growing epidemic"

The yellow star are to highlight that the 
y-axis (left-hand side values) in 2014
is set to a higher maximum value
than for 2012/2013.
Click on image to enlarge.
The 2 healthcare-associated clusters (paramedic cluster and Jeddah cluster) are the driving factors underpinning the case number spike in April. Cases in other regions are either linked or relatively few in number.

Click on image to enlarge.
With a dozen new cases noted by the United Arab Emirates (UAE) early this morning (my time) I've updated the case and epidemic curve chart below as well, again. This makes UAE the clear second place hotzone for MERS-CoV cases. 

Whether these cases, all asymptomatic, are liked to the paramedic cluster or just the result of enhanced testing (there was mention of contacts in the media release though) is unknown and awaits clarification as do more details on most of the recent 90 cases .

Click on image to enlarge.
And lastly for this post, a chart I last updated 18-Mar when there were fewer then 200 cases. Ahh the good old days. How a month and a couple of healthcare outbreaks change things. This shows the total cases, obviously driven by the Kingdom of Saudi Arabia, but adds on those from the UAE and Yemen as well. A very interesting feature here is the current proportion of fatal cases. The PFC sits at 32.7%; the lowest proportion of fatal cases in the history of MERS-CoV. Why? Because the denominator in that equation (total case numbers) has sky-rocketed without an accompanying rise in fatal cases. While some of the recent cases may yet succumb to severe MERS, the spike we've seen in cases without any disease or with only mild disease, who probably won't die, will offset that and the PFC looks to remain lowered. I would very much like someone to tell me whether these increased numbers of mild cases are due to a change in the approach to testing (contact me!) of people; more testing and less watching and waiting to see if contact and other become obviously sick. Either way - this is great to see.

So this last chart really hammers home one good reason to include asymptomatic cases in the tallies; we get to see the full spectrum of disease from MERS-CoV infection, including no disease at all

Knowing that gives us some much needed context when we see a headline that reads "killer virus spreads". 

Now if we just knew whether asymptomatic cases spread infectious virus either through occasional coughs or sneezes or by contaminating their environments. Baby steps.