Showing posts with label Discrepancies. Show all posts
Showing posts with label Discrepancies. Show all posts

Wednesday, March 25, 2015

Confusion surrounds the number of H5N1 cases in Egypt



The most recent, cumulative World Health Organization (WHO) table of human H5N1 cases was published on March 3, 2015.[1] This table notes a total of 88 human H5N1 cases in Egypt through March 3, 2015. As I noted previously [2] the tabulation of counts based on the line list of cases published in the monthly risk summaries only totals 82 cases for Egypt in 2015 based on onset dates in reports of 2015.

To understand the confusion in the Egyptian case counts in the WHO table, it is necessary to consider the 2014 totals provided by WHO. The current WHO cumulative table reports 46 cases of H5N1 in 2014 with 31 cases from Egypt.[1] However, individual enumeration of WHO-confirmed H5N1 cases based on line lists in the monthly risk assessments shows a total of 52 H5N1 cases in 2014 (based on onset dates), with 37 of these reported from Egypt.[3] The table below identifies the distribution of WHO-confirmed H5N1 from Egypt by each of the monthly summaries for 2014 through the most recent assessment posted on March 3.[4]



Further complicating the confusion is the Regional Office Eastern Mediterranean (EMRO) of WHO. On March 21, 2015 EMRO published a table that only identifies 29 H5N1 cases from Egypt in 2014.[5] The EMRO data has a 8-case discrepancies with the line list of confirmed cases published by WHO.

In summary, Egypt experienced a total of 37 confirmed H5N1 in 2014 based on onset dates. In 2015, 82 WHO-confirmed cases with onsets dates before February 20 have occurred in Egypt. Since February 20, there have been at least 22 additional official cases from Egypt with onset dates on or after 20 February. Another 3 H5N1 cases have been also reported from Egypt but are not yet corroborated.

Until we get the numbers right for H5N1 in Egypt from 2014, we can’t correct the numbers for 2015. Based on the above discussion, through March 25, 2015 there have been 107 H5N1 cases in Egypt with symptom onset since January 1, 2015.  








Tuesday, November 4, 2014

Has WHO overlooked 5 MERS cases in Saudi Arabia?



Previously, I discussed discrepancies between the MERS case counts for the World Health Organization (WHO) and the European Centre for Disease Prevention and Control (ECDC) (link). The WHO case count differed from the number posted on the Saudi Arabia Ministry of Health website by 15 cases. At least 12 cases previously announced by the Saudi Arabia Ministry of Health had not yet been posted in Disease Outbreak News by the WHO through October 21, 2014.

Yesterday the WHO reported in aggregate 12 new MERS cases from Saudi Arabia from the period October 18 to October 26, 2014 (link). These 12 cases do not equate to the 12-case differential noted in my previous post. The most recent WHO report regarding cases from Saudi Arabia (October 16 link) only enumerates cases through October 11, 2014. However, between October 12 and October 16, the Saudi Arabia Ministry of Health website announced five additional MERS cases, Taif (3), Riyadh (1), and Al Karj (1).

Hopefully, the WHO will report these cases in the future or discuss why they are not included in the total count for MERS cases from around the world.

Links to five Saudi Arabia MERS Cases (October 12-16)




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 FluTrackers.com (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

Jordan

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).

Philippines

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.

Qatar

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.

Turkey

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.

 

Thursday, June 19, 2014

Discrepancies in the World Health Organization’s Count of MERS Cases in Saudi Arabia



With Saudi Arabia reporting more than 80% of all Middle East Respiratory Syndrome (MERS) cases to date, detailed information about the individual cases from Saudi Arabia is critical to understanding the nature and spread of this novel disease. There are some discrepancies among the MERS cases reported by World Health Organization (WHO) from Saudi Arabia. Of course, WHO is constrained by the quality of data provided by its various member states.

Generally, WHO provides detailed information on the initial cases of a novel disease outbreak in its online publication, Disease Outbreak News (DON). The first WHO report of a MERS [novel coronavirus] infection was published on September 23, 2012. Between September 2012 and April 16, 2014, WHO reported details on 228 MERS cases with varying levels of details provided by the reporting member states. Of the 228 cases reported by WHO though that date, 181 were individually reported cases from Saudi Arabia. The DON of April 14, 2014 (15 reported cases from Jeddah and Riyadh) was the last Saudi Arabian case-by-case report from WHO. After that date, WHO only provided aggregate case totals from Saudi Arabia. These aggregate totals were embedded in 6 DON reports between May 7, 2014 and June 13, 2014 as noted in the table below.

On June 13, 2014, WHO provided a summary of these aggregated cases. According to WHO, 402 cases were summarized. However, a tally of the WHO totals from the previous DONs indicates that only 401 cases were actually aggregated. A comparison of the WHO total with media reports from the Saudi Arabia Ministry of Health indicates that 404 MERS cases were publicly reported by the Ministry of Health.

For the period between April 11, 2014 and May 4, 2014, WHO reports 229 cases from Saudi Arabia, although the Saudi Arabia Ministry of Health only publicly reported 228 cases during that period. One possible explanation is that the 51 one-year-old individual from Riyadh reported on April 9, 2014 by  the Saudi Arabia Ministry of Health (link FluTrackers case # 227), not previously enumerated by WHO, was added to the aggregate total (see: link). Also,  between May 5, 2014 and May 9, 2014 Saudi Arabia Ministry of Health reported 62 MERS cases. During this same period WHO only reported 58 cases in aggregate (see: link). It is possible that WHO failed to incorporate four cases into its cumulative tally for this 5-day period in Saudi Arabia.

With the reporting of specific case details of two individuals from Saudi Arabia in DON on June 16, 2014,  WHO has now apparently returned to reporting individual case details from Saudi Arabia. Better individual case details may again be flowing from Saudi Arabia to WHO.

Depending on the quality and accuracy of the data provided by Saudi Arabia, a discrepancy of 3 or 4 cases among more than 500 reported cases falls within a reasonable error factor. Such differences will not appreciably affect interpretations or speculations drawn from such a large sample of cases.

Of more serious concern is a report on June 3, 2014  by the Saudi Arabia Ministry of Health indicating retrospective reporting of more than 100 additional MERS cases in Saudi Arabia (and acknowledged by WHO - link) going back to May 2013 (See: The Saudi Arabia Ministry of Health Quietly Announces an Additional 113 Cases of MERS). This means that from May 2013 through April 2014, about 15% of all MERS cases in Saudi Arabia were unreported. A 15% error factor is unacceptable when public health officials and the rest of the world are trying to understand the nature of a novel infectious disease with a high fatality rate.
 

Friday, February 28, 2014

A total of 374 H7N9 cases through February 27, 2014



The World Health Organization  (WHO) has not been providing cumulative case counts of H7N9 cases in their Disease Outbreak News reports. This may be due to incomplete and inconsistent case information that has been provided to WHO by the National Health and Family Planning Commission (NHFPC) of China.

Perhaps the most accurate enumeration of H7N9 cases is provided by the Centre for Health Protection (CHP), Department of Health, Hong Kong Special Administrative Region.They report


"As of yesterday (February 27, 2014), a total of 367 human cases of avian influenza A(H7N9) have been confirmed in the Mainland, including Zhejiang (136 cases), Guangdong (81 cases), Jiangsu (42 cases), Shanghai (41 cases), Fujian (20 cases), Hunan (16 cases), Anhui (nine cases), Jiangxi (six cases), Beijing (four cases), Henan (four cases), Guangxi (three cases), Shandong (two cases), Guizhou (one case, imported from Zhejiang), Hebei (one case) and Jilin (one case).cases), Shandong (two cases), Guizhou (one case, imported from Zhejiang), Hebei (one case) and Jilin (one case)."


The 367 cases are only those reported from the mainland of the People’s Republic of China (PRC). The two imported cases reported from Taiwan and the single imported case reported from Malaysia need to be added to this total. Surprisingly, the four H7N9 confirmed cases from Hong Kong are also not included in the CHP total. 

A review of the CHP cumulative totals by province with publicly available information suggests that there is a discrepancy of one case in the count for Zhejiang Province (possibly FluTrackers’ case #182 because WHO reported this as a Shanghai case).  Also, in several reports on the initial 2013 cases from Shanghai, there is conflicting information about which cases actually died and whether or not one or more cases were only suspected cases. Confusing the situation even further is that at least one asymptomatic child from Beijing in May of 2013 is not included in the official counts.

It would be beneficial if public health agencies and international health organizations would make their line list of cases publicly available for scrutiny. In any event, through February 27, 2014, a total of 374 H7N9 cases have been officially reported since March 2013.