Thursday, October 30, 2014

Comparison of WHO and ECDC MERS case counts

As of October 16, 2014, the World Health Organization (WHO) reported a total of 877 cases of Middle East respiratory virus syndrome (MERS) from WHO member states (through October 11, 2014 link).  The European Centre for Disease Prevention and Control (ECDC),  a European disease monitoring organization established in 2005 (link), has reported a total of 906 MERS cases from around the world through October 21, 2014 (link). Both WHO and ECDC provide updates on the MERS outbreak, however neither these agencies provides a publicly available line list of cases.

Because it appears that the next MERS wave has started on the greater Arabian Peninsula in the Middle East, is worth discussing the apparent discrepancy in the number of MERS cases between the WHO and the ECDC.  

The table below compares the current counts of MERS cases for WHO and the ECDC through specific dates.  The differences in the case counts are discussed below by country.  WHO and the ECDC enumerate cases based on the reporting country (under IHR), rather than the source country of infection.  Also included in the table below is a column with the case counts that have been tabulated by (link). The FluTrackers’ case counts are not directly comparable to the WHO or ECDC data because the FluTrackers’ counts are based on the country of the source of infection not the reporting country.

There are minor discrepancies between the WHO case counts and the ECDC case counts as noted in the detailed discussions below. It would be beneficial if both of these organizations would make their line list of cases publicly available on the internet.

Discussion of table discrepancies between WHO and ECDC


The case count noted by WHO for Jordan does not appear to include the seven retrospectively confirmed cases from the first MERS cluster in Jordan in 2012 (link).


The WHO does not recognize any cases from the Philippines. At least two possible MERS cases have been reported from the Philippines. The first was a male nurse who tested positive for MERS in United Arab Emirates and later tested negative in the Philippines in April, 2014 (link). The second was a female nurse who was tested in Saudi Arabia and arrived in the Philippines after the positive test results were announced by Saudi Arabia (link). It is not clear which case, if either, of these two cases is included as a case from the Philippines by the ECDC.


On October 12, 2014, the Supreme Health Council of Qatar officially announced the first MERS case in Qatar in 2014 (link), so  the WHO may report his case in the future.

Saudi Arabia

As of October 21, 2014 the Saudi Arabia Ministry of Health web page reports a total of 771 MERS cases. The ECDC count for MERS cases from Saudi Arabia is 771, matching the Saudi Arabia Ministry of Health total.

The last official WHO update prior to October 21, 2014 was published on October 16, 2014 (link). At that time, the WHO case count for Saudi Arabia was apparently 756. There is a disparity of 15 MERS  cases between the WHO case count and the ECDC case count for Saudi Arabia. This difference appears to be a function of differential reporting dates rather than major disparities in the case counts. Between  October 11 and October  21, the Saudi Arabia Ministry of Health reported a total of 12 MERS cases that will probably be reported and incorporated in the WHO count in the near future.  

This would bring the WHO total through October 21 to 768.

The reason for the difference of three cases between the WHO data and the ECDC data is uncertain. Any number of additions and deletions (due to duplicates and false positives) in the case counts could affect this differential in the case counts.


The first MERS case in Turkey was only reported on October 17, 2014 (link). The WHO later reported this case on October 24, 2014 (link).

United Arab Emirates

It is not clear how the ECDC determined an additional four cases from United Arab Emirates compared to the WHO counts.


Wednesday, October 15, 2014

Comparing WHO and CDC Projections of Ebola Cases in the Future

Through October  12, 2014, the World Health Organization  (WHO) has reported more than  8900 cases of Ebola since this epidemic began  (link).  The outbreak is currently out of control in three countries in West Africa, Guinea, Liberia, and Sierra Leone.  The graph below depicts the timeline of the growth of the  cumulative number of total cases reported by  each of these countries.  


The overall cumulative Ebola case total time series can be fitted to an exponential growth curve to project the total number of cases going into the future. The WHO data indicate that by January  2015 there will be almost 45,000 Ebola cases as shown in the graph below.


There is no doubt now that this outbreak will not be contained in West Africa by the end of December.  How many future cases of Ebola will there be is difficult to predict. WHO has noted on several occasions that the officially reported numbers under represent the actual number of cases and deaths in these countries.

On the other hand,  The US Center for Disease Control  (CDC) has projected cases counts ranging from 550,000 to 1.4 million cases in Sierra Leone and Liberia by mid January 2015 (link).  The CDC adjusted  existing case counts by a factor of 2.5 according to their model (as of August 28, 2014).  The graph below compares the differential growth rates based on current WHO data and the estimated case count by the CDC.  According to the CDC estimates, there are now at least 22,000 Ebola cases in West Africa compared to the 8900 reported by WHO.

The graph indicates the clear disparity in the different estimates by these two health agencies of the future case count of Ebola.  As we edge closer to the end of 2014 we will have a better idea of which projection is more accurate.

Where does the WHO estimate of 5,000 to 10,000 new Ebola cases in December come from?

The number of Ebola infections in West Africa continues to increase at an alarming rate (link).

As the official international public health agency, the World Health Organization (WHO) is tasked with tracking and reporting on infectious diseases around  the world.  As of October  14, 2014 the WHO has reported more than 8900 Ebola cases from the three West Africa nations of Guinea, Liberia, and Sierra Leone, where the Ebola outbreak has not yet been contained (link).

Below is a chart showing the continued rising number of new cases by week number in these three countries.  The data in the chart is based on official WHO data through October 12, 2014 (link).  A quote from Dr. Bruce Aylward,  a WHO spokespersonindicates that by mid December 2014 between 5,000 to 10,000 new weekly Ebola cases could reported in the three West African countries  (link).

The next graph below shows the temporal progression of the increases in new cases with a trend line projecting news cases into the coming weeks. The exponential trend line from the current  WHO data projects 5,000 to 10,000 new weekly cases of Ebola in West Africa by December 2014. This is the basis of Aylward's comments yesterday.

Tuesday, October 7, 2014

Crowd sourcing for a solution to the West African Ebola epidemic

 With the current Ebola outbreak raging in West Africa and with no immediate solution in sight,  the U.S. Agency for International Development (USAID) has proposed an online challenge to think "outside the box" regarding solutions for the current Ebola crisis.

Today, USAID launched the Fighting Ebola: A Grand Challenge for Development with a call to innovators around the world to submit ideas focused on improving the tools used by frontline healthcare workers in the fight against Ebola in West Africa. The initial focus of the Challenge, as announced by President Obama on Sept. 26, is to generate pioneering solutions to improve the personal protective equipment (PPE) and tools used by healthcare workers battling Ebola.

The Fighting Ebola Grand Challenge will help to identify innovations that improve the comfort while maintaining the safety of PPE – masks, gloves, boots, and other protective gear used by healthcare workers.

The website is an open innovation platform to crowd source and incubate innovative ideas to improve delivery of care and stem the spread of disease, including improvements in PPE;  a  challenge competition to fund and test innovations for PPE, infection treatment and control; and  partnerships for rapid testing and deployment of the best solutions.

To share your ideas or to join the conversation, visit

Map: Countries with Confirmed Ebola Cases from the 2014 Outbreak

As of October 6, 2014, seven countries have reported cases of Ebola as noted below.  The Democratic Republic of Congo has reported at least 53 cases from a local Ebola outbreak (link)  not associated with the current outbreak that apparently originated in Guinea in December 2013 (link).  

Guinea (977 confirmed cases) link
Liberia (931 confirmed cases) link
Nigeria (19 confirmed cases) link
Senegal (1 imported infection) link
Sierra Leone (2179 confirmed cases) link
Spain (1 locally acquired infection) link
United State of America (1 imported infection) link

Monday, October 6, 2014

Spain: The First Locally Acquired Ebola Infection in Europe

A health care worker in Spain is the first individual outside of Africa to locally acquire an Ebola infection.  A nurse treating an Ebola case in a Madrid hospital in September has tested positive for Ebola (link). The nature of transmission from the Ebola patient to the nurse has not yet been reported.  The reports from the Ebola outbreak in Africa show that health care workers are frequently infected and die from treating Ebola patients (link). It was widely assumed that health care workers in the West Africa countries became infected because of lack of adequate PPE, proper training, and overwhelmed facilities. This new case in a European hospital raises concerns about the nature of Ebola transmission in hospital settings everywhere in the world.   

The Ebola case in Texas, USA, will provide an additional test of the nature of transmission of this virus (link). So far no secondary cases have been reported in Texas. It will be several more weeks before Texas can claim no additional secondary cases of Ebola.