HEALTH officials have urged for people to take extra precautions against coronavirus – after a national IT error left over 150 cases in the borough stuck in the system.

Latest government figures showed 500 new cases of covid-19 had been added to Bolton’s total infections over the weekend.

The borough's infection rate has been adjusted to account for the newly revealed cases, with the rate change showing that around 155 cases from people tested in the week up to September 29 were missed from the original statistics.

A spokesperson for Bolton Council said: “Our Public Health Team has worked over the weekend to understand what impact this has had on our rates.

“Our rate remains high - our borough now shows a rate of 231.3 cases per 100,000 for the period up to 29th September, whereas previously it was 177.0.

“We still need everyone’s help to stop the spread of the virus. We are strongly advising that households do not mix inside public places, stay 2m apart, wear face coverings in all enclosed spaces and keep washing your hands.”

It is believed that the spike in newly recorded cases has been caused by a technical error which caused 15,841 cases confirmed between September 25 and October 2 to be left out of the daily updates.

It is understood that the glitch was caused by the Excel spreadsheet, used to process the data, reaching its maximum file size, preventing an automatic process from adding new names.

The file has now been split into multiple smaller documents to prevent the issue from happening again.

Officials said the data published over the weekend are “artificially high” – because they include cases from as far back as September 25.

The oldest case added to official statistics for Bolton appears to be from a test taken on September 14, three weeks ago.

Speaking in the House of Commons, Matt Hancock said: “I want to reassure everyone that every single person that tested positive was told that result in the normal way in the normal timeframe.

“They were told that they needed to self-isolate, which is of course now required by law.

“However, these positive test results were not reported in the public data and were not transferred to the contact tracing system.”

All cases have now been transferred to the contact tracing system, and more than half of those with the virus who were previously not contacted have now been reached.

IT experts have questioned why Public Health England used Excel for a scheme as large as NHS Test and Trace.

Computing experts and academics said it is “very surprising” that Excel was used for something of this scale and said such a system should have been adequately tested.

Jon Crowcroft, Marconi Professor of communications systems from the University of Cambridge, said file size is a “basic consideration”.

“One would think that a software engineer would have considered a worst-case test scenario for any system design – on paper before you even get to writing code – just to make sure it wouldn’t blow up in any way like this,” he explained.

“The limitations of Excel in terms of big data, which is generally a very decent piece of software, are well-known – if you look at how many people are expressing astonishment at this online, you can see that.”

He continued: “There are many big systems in Government (eg DVLA’s or HMRC’s) that work at this scale so there’s no excuse.

“Also, a simple sanity check on the data or error checks in the system might have told them when they hit this limit instead of discovering it after the event.

“This sort of thing is standard in sixth form or undergraduate computer science training too.”