Excel file glitch leads to 16,000 cases in UK being missed

LONDON • A technical glitch that left nearly 16,000 Covid-19 cases undocumented in Britain was caused by Microsoft Excel files exceeding their maximum size, the country's Health Secretary has said.

The error "should never have happened", Mr Matt Hancock told the House of Commons, promising that the government would investigate the matter and upgrade its outmoded computer systems.

The Health Secretary on Monday gave Members of Parliament a rundown on how the 15,841 positive test results recorded between Sept 25 and last Friday were not reported in the country's daily figures - and, critically, were not passed onto the tracing programme.

Those who tested positive were informed of their results but were not then called by tracers - meaning anyone whom they had close contact with had also not received instructions to self-isolate. Scientific experts say that must happen within 48 hours for a test-and-trace programme to be effective.

Mr Hancock said there was a failure in the "automated transfer of files" from laboratories to Public Health England (PHE).

"This incident should never have happened. But the team have acted swiftly to minimise its impact."

PHE said the glitch, discovered last Friday, had been fixed, and outstanding cases passed on to tracers by the next day.

But, by Monday, around half of those positive cases still had yet to be asked about their close contacts.

The disclosure of the glitch brought a storm of criticism on Prime Minister Boris Johnson's government, which has been on the defensive for its haphazard handling of the pandemic.

More than 42,000 people have died from the virus in Britain, the highest number in Europe, and the country is facing a second wave of infections. Britain's government coronavirus dashboard yesterday showed a total of over 530,000 Covid-19 cases reported to date.

The opposition Labour Party said the missing results were "putting lives at risk", with "thousands of people blissfully unaware they have been exposed to Covid-19".

The error was caused by the Microsoft Excel data files being too large to transfer after they were compiled, BBC reported.

PHE had set up an automated process to pull together text-based lists of data collected by firms paid to carry out Covid-19 swab tests.

The data was compiled into Excel templates that were uploaded to a central system and made available to the National Health Service's test-and-trace team.

But PHE developers picked an old file format, .xls, to do this. As a result, each template could handle only about 65,000 rows of data rather than the one million-plus rows that Excel is capable of.

When the total was reached, further cases were simply lopped off.

Officials said that they eventually fixed the problem by splitting up the files and transferring smaller amounts of data.

The glitch meant the number of new daily cases reported over that week was lower than the actual number. Daily figures for the end of the week were about 10,000 rather than the 7,000 initially reported.

BBC analysis found that the number of cases reported for the week to last Thursday rose by around 93 per cent in the North West after accounting for the error - with similar rises reflected across Britain.

"The timing of it couldn't be worse," said Professor Devi Sridhar, director of the global health governance programme at the University of Edinburgh. "You're heading into winter, and we already knew that cases were rising. This is really when you'd need your test-and-trace system to do its work."