An average of more than 350,000 daily new cases of Covid-19 in the UK are estimated to have been seen in early January.
According to new analysis, that’s more than double the official number reported on the government’s virus dashboard over the same period.
The figure is down from nearly 500,000 new cases a day estimated for the end of December – though this was nearly three times the dashboard total.
The analysis has been published by the Office for National Statistics (ONS) and shows just how many new cases of coronavirus are still being missed in the official figures.
An average of 163,600 new cases per day were recorded from January 2 to 8, according to the dashboard.
But the true number was likely to be nearer 358,500 a day, according to the ONS modelling.
And while the dashboard recorded an average of 173,500 new cases a day for December 26 to January 1, the ONS puts the figure at 479,100 a day.
The sharp difference in totals reflects the limitations of the dashboard, which only counts people who have reported themselves as testing positive for the virus.
This means the numbers are affected by how many people are deciding to take a test, how many are choosing to report their results, and how many are taking a test because they know they have symptoms.
By contrast, the ONS figures are based on analysis of nose and throat swabs taken from a representative sample of more than 150,000 people in private households.
The same people are sampled every week, regardless of whether they know they have Covid-19 or have reported a positive result.
The ONS then produces estimates of the likely number of new cases of coronavirus per day across the country.
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The estimates for January 2-8 have only been published now due to the time needed to collect and process the data.
The number of new cases reported by the government has always been lower than the level estimated by the ONS, but the gap has become wider since the arrival of the Omicron variant.
High levels of under-reporting will still be affecting the government’s daily figures, meaning the true volume of cases in the UK is increasingly unclear.
The dashboard numbers are currently limited to all positive lab-confirmed PCR test results in the UK, plus positive lateral flow tests in Northern Ireland and, in England, any positive lateral flow tests not followed by a negative PCR test taken within 72 hours.
From January 31 the dashboard will also include figures for possible Covid-19 reinfections in England – though again this data will be affected by how many people are reporting their test results.
More data from the ONS also shows that in the week ending January 22, the percentage of people testing positive for Covid-19 was highest for those aged two to 11, with 11.8% tested returning a positive result.
That's up from 5% when children went back to school after Christmas. Compare that to the over 70's, where the infection rate has dropped to just 2%.
Children under-12 cannot get a vaccine yet, which explains this age group's high level of infection compared to older adults who are likely to have all three doses.
Leading scientists are currently considering whether to recommend to the government that children in this age group should be vaccinated, however, others are questioning whether it is really necessary at all now that the majority of the elderly have coronavirus antibodies and children are much less likely to become seriously ill with the respiratory illness.