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Time for an Upgrade: UK Health Agency Missed 15,000+ COVID Cases by Using Outdated Excel Format

Microsoft Excel Office 97 spreadsheet
Photo by Collin Anderson.

October 6, 2020 - Public Health England (PHE) announced that information for 15,841 COVID-19 cases were not recorded in the agency’s daily reporting due to a spreadsheet oversight. Basically, PHE’s spreadsheet, which was based on an old Microsoft Excel format, ran out of rows to hold all the data.

The PHE’s Excel spreadsheet used the old XLS format that is limited to 65,536 rows of information and was phased out by Microsoft 13 years ago (yes, 13 years ago). Newer versions, beginning with Excel 2007 (as in the year 2007) are saved as XLSX files and allow for 1,048,576 rows of data, or 16 times more capacity than what PHE was using.

In a statement issued by PHE, the technical issue was identified on Friday, Oct. 2, 2020. It was determined over 15,000 cases were not captured by PHE’s reporting system between Sept. 25 and Oct. 2, with the bulk of missing cases occurring toward the end of that period.

PHE’s Interim Chief Executive Michael Brodie said in the press announcement, “Every one of these cases received their COVID-19 test result as normal and all those who tested positive were advised to self-isolate.”

While the error did not impact people waiting to receive their COVID-19 test results, it did delay the government’s contact tracing efforts to notify people that may have come in contact with an infected individual.

Public Health England sign
Photo courtesy of Public Health England

Once discovered, the missing cases were properly transferred to the National Health Service’s Test and Trace contact tracing system for processing. The PHE announcement said the overlooked cases were prioritized for contact tracing.

Test and Trace and PHE Joint Medical Advisor Susan Hopkins said, “We fully understand the concern this may cause and further robust measures have been put in place as a result."

According to an Oct. 5, 2020, BBC article, while each XPS spreadsheet can hold about 65,000 rows of information, each reported case uploaded to a spreadsheet requires multiple rows of data, so a single spreadsheet might include information on approximately 1,400 cases. If the data being uploaded to PHE was larger than 65,536 rows, the additional information would be ignored in the upload, which is what appears to have happened in this situation.

Had PHE used the newer Excel format (and by newer, again, the format that’s been available since 2007) it would not have reached Excel’s upper row limits for some while longer. Furthermore, there are other data tools instead of Excel that PHE programmers could have considered using that are better suited for compiling information as large as the country’s COVID-19 cases.

The PHE was established “to protect and improve the nation’s health and wellbeing, and reduce health inequalities,” according to its website. The agency was established in 2013 to bring together health specialists from over 70 organizations into a single public health service.

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