Explanation of why daily Covid-19 numbers don’t always seem to add up

As the daily figures of lab-confirmed Coronavirus cases rise, many readers have been keen to understand how the data works. OnTheWight helps explain the figures

Lost and Confused Signpost.

As there has been some confusion over the daily figures coming from Public Health England of those who have tested positive for Coronavirus (Covid-19) and how that number breaks down, OnTheWight thought it would be useful to provide some clarification for readers (jump to explanation).

The current figures
Six weeks since the first confirmed case of Covid-19 on the Isle of Wight and the number of lab-confirmed cases has risen to 82.

  • 19 patients have sadly passed away
  • 21 patients have been treated in hospital, recovered and sent home
  • As of last week the number of patients being treated in the hospital was in single figures
  • Around 30ish other cases

Many readers have wanted to know:

From the beginning
The first lab-confirmed case of Covid-19 on the Isle of Wight was recorded on 7th March 2020 and was an Islander who had recently returned home from travels abroad.

It’s unclear, but likely there were already people on the Island with the virus before that date, who had not been tested, but simply were coping with their symptoms at home.

Where are people tested?
In the initial stages of the outbreak, testing was carried out in a number of settings, with contact tracing taking place – Public Health England were contacting those who had been in touch with confirmed cases.

National decisions then led to this phasing being changed and OnTheWight understands that tests are now predominantly being carried out at St Mary’s Hospital, with some are taking place at nursing or care homes.

An Isle of Wight Council spokesperson told OnTheWight,

“We can confirm that there is a mechanism for both residential care homes and nursing homes to request testing of symptomatic residents. 

“This is in accordance with government guidance which provides for testing for patients admitted to hospital who meet the criteria and  testing in settings where there is a possible outbreak of Covid-19 including residential and nursing homes.”

Patients being treated in hospital
St Mary’s Hospital will not confirm the exact numbers of those being treated. As you would expect, it’s an ever-changing number, so instead Maggie Oldham, IW NHS CEO, explained last week that the numbers were still in single figures.

However, what we do know is that the Intensive Care Unit (ICU) is normally a six-bed unit, but has been extended to being an 18-bed unit – which currently is not full.

Planning is in place to extend that further to 48 beds if the need arises, but more staff and equipment would have to be sought.

The field hospital set up with the help of the Scots Guards is intended as a recovery area for those before discharge.

Addressing the ambiguity of the ‘other’ numbers
There has been some ambiguity around the remaining 30-ish people who have tested positive for Covid-19 but don’t fit into the category of being currently treated at the hospital, having been treated but discharged, or having passed away.

Unfortunately for those keen to seek an answer about these numbers, it’s not straightforward for a number of reasons.

Firstly the test results are attached to your postcode, so if you were someone who worked off the Island and were tested in that setting and perhaps remained in hospital there, you would be part of the Isle of Wight’s count for lab-confirmed cases.

Number includes those in care homes
OnTheWight understand that changes in phasing of testing means that a number of those people would be at home or in the community having had confirmed test results.

An Isle of Wight Spokesperson told OnTheWight,

“Information on lab-confirmed COVID-19 cases are published by Public Health England (PHE) and displayed on the national COVID-19 dashboard. These are cumulative case counts of patients who are currently unwell, those who have recovered and those that have died.

“They are based on the home postcode of the person tested. So they include hospital admissions, cases in the community (including care homes) and anyone who gives their residential address as the Isle of Wight.

No breakdown available
Isle of Wight Public Health said they did not hold information on the breakdown of the figures, so at the moment it’s unclear how many of the 30-odd people mentioned above are in a care home or simply at home managing symptoms after testing positive for Covid-19.

It’s an ever-changing situation and as with all data, these figures come with a number of caveats. OnTheWight will continue to share the daily data from Public Health England.

Image: wildrose115 under CC BY 2.0

Friday, 24th April, 2020 6:47pm


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Filed under: Health, Island-wide, Isle of Wight News, Top story

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6 Comments on "Explanation of why daily Covid-19 numbers don’t always seem to add up"

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Rhos yr Alarch

Thankyou for doing your very best to provide an explanation!


Thanks for coming back on this and providing further clarification.


I’d like to add my thanks to you Sally, for that. It seems to me that the most significant numbers are those that have been treated in hospital and passed away, those that have recovered and those currently in hospital. The postcode issue does rather complicate it though.


Thank you for the explanation.

Given that only serious cases are included and the vast majority of cases are minor and hence ignored do these figures have any value?

Trying to answer the questions posed by AH I would say:- The information can worry and reassure depending on how it changes over time, and that’s why it should be as accurate as possible. Whichever way the numbers move will have no bearing on how I react to the measures in place to reduce transmission since I adhere to them rigidly in order to reduce the risk… Read more »
Angela Hewitt

Now that you know all this information how does this help in your personal life. Does it reassure you? does it worry you? Will it help you make a decision about how you handle lock-down? Does it make you think things are getting better or worse?