Random Analytica

***** Please note that this post reflects data, graphs and infographics of the Avian Influenza A(H7N9) virus and was updated with public source information from late 22 Apr to early 23 April 2013 CET *****

The avian influenza A(H7N9) virus which first struck Shanghai in mid-February when an 87-year old Shanghai resident fell ill with flu/pneumonia like symptoms, then subsequently died two-weeks later continues to cause disruption in China.

Like previous outbreaks of respiratory disease, this new strain designated by the World Health Organisation (WHO) as avian influenza A(H7N9) has the potential to cause major issues for the World’s second largest economy and like SARS previously to spread internationally.

It should be noted that I’m not a medical specialist (although I did spend a very happy year working in an Operating Room Suite as an Anaesthetic Secretary). I do love data so each day (when available) I’ll try to present a range of analytics using the most recent information so that you can tap into this event with some evidenced based data.

Case Fatality Rate

In the past 24-hours there have been three more cases and one more fatality (preliminary, still awaiting confirmation from the WHO) which brings the total to 105-cases including 21-deaths. This equates to a case fatality rate of 20%. For context SARS was 10.9%.

There was one confirmed patient discharge and I was able to review the data again to add a further 3 discharges, thus bringing the confirmed recoveries up to 13 (12.4%).

The most recent fatality reported was on the 22nd April 2013 via Shanghai Health Department (thanks to Michael Coston for the tip).

Here is an infographic looking at those being treated, fatalities and patients that have been discharged from treatment. Where I have been able to confirm the details I have broken the groups into male/female sub-groups.

Epidemiology

The next graph is an epidemiological analysis of cases, including deaths and patients who have recovered using the onset of the illness. Currently I have been able to verify the illness onset dates of 100-patients all of which have been included in the following graph.

I was also able confirm all of the ranged onset date ranges via the Chrome translation tool which will have stabilised the data a little further, especially now we are getting to a decent sampling size.

Possibly controversially I have decided to input the two sons (one of whom died, one recovered) who potentially contracted the disease within a family cluster from the last known date range they were admitted to hospital for pneumonia (19 – 24 February 2013).

Please note that WHO issue a similar report on a weekly basis.

Cases by Municipality/Province

The next infographic is a look at the 105-cases by Municipality (in the case of Beijing and Shanghai) or Province.

At this stage the bulk of the official reported cases have been in the Zhejiang Province (38.1%) followed by the Shanghai Municipality (32.4%) and Jiangsu (21.9%).

At a regional level the cases are almost entirely confined within the East China Region (96.2%), represented by the blue section in the infographic.

The big story today will be the first instance of avian influenza A(H7N9) in the Shandong Province and the slow spread outside of Shanghai.

Prior to this in East China only Henan and Beijing had recorded instances of H7N9, although to date no deaths have been reported in these areas.

Presentations by Age Group

Here is a look at those presenting with avian influenza A(H7N9) by their age cohort.

Of the 102-cases where age data is known the average age was 58.3-years and 45.1% of the patients were aged 65 or greater.

Currently only four cases were under the age of 24, three children (ages 2, 4 and 7) and a 21-year old female from Jiangsu. I have not included the 4-year old asymptomatic case in Beijing reported in mid-April.

Age at Death

Of the 19-cases where death has been verified the average age was 63.3-years and 52.6% of the deaths were recorded in those over the age of 65.

The youngest person to die was a 27-year old butcher from Shanghai with a history of hepatitis B. Being amongst the first victims of the disease he did not receive antiviral treatment until the second week (the recommended window for this treatment should be two days) and succumbed to the disease after 12-days.

Summary

Not much analysis today, it was all about double checking and cleansing the data I had and reviewing source material (a hard grind).

Updates (23/04/2013)

• Updated the WHO SARS case fatality rate with a later study that put the CFR at 11.9% (not 9.6%). Many thanks to Helen Branswell (@HelenBranswell) for picking this up.