The failure of the government’s testing strategy (Report, September 22) is a lesson in confusing resources with capabilities. Commercial NHS test and trace has resources but not capabilities. NHS labs and local authority directors of public health supported by Public Health England have capabilities but not resources.
In order to resolve this conundrum, we should provide the experts who are custodians of those capabilities with the resources they need to do their job.
Duncan Robertson School of Business and Economics, Loughborough University Leicestershire, UK
Long Interview on BBC Five Live debating against a herd immunity strategy
Interview on LBC (Nick Ferrari) and LBC (Iain Dale)
Here is the heatmap of cases for PHE week 41 using week 40 data.
Studies in Spain, France, and the US have all shown that although the second wave may start in young people, it will inevitably move to older people.
The remarkable thing about this disease is that the death rate increases massively with age.
Students are unlikely to die of Covid-19, although some may, and we are still unsure about the long-term health consequences from catching the disease.
The heatmap of cases shows how the disease has travelled through the age groups. As you go from left to right through the weeks, you can see a gradual rise upwards through the population.
These figures should be seen as a minimum. Lack of testing capacity has meant that not everyone can get a test. For example, we do not know whether delays in testing may be concentrated in certain groups such as care home residents.
The latest figures (which will be revised upwards as new cases are recorded) show a very worrying number of cases in the over-80s.
A case rate of 53 per 100,000 over-80s is very concerning. The Department of Health and Social Care have this week stopped publishing the COVID-19 surveillance report which broke down numbers of people with the disease. However, we can estimate that over 1,000 over-80s tested positive last week. Given the very high fatality rate in over-80s, we can confidently predict that over 100 over-80s will die of infections caught in the last week.
This is one of many reasons why interventions are so critical – by not clamping down hard on the disease now, we will sleep walk into a situation as bad or worse than the first wave. The mid-July Academy of Medical Sciences report commissioned by the Chief Scientific Adviser set out a reasonable worst case scenario of 119,000 deaths in this second wave excluding those in care homes. We have a choice as to whether we as a nation repeat the mistakes of the past.
We also know that we are not doing enough testing as the positivity rate is so high (7% overall for Pillar 2 tests and up to 15% in some areas such as Liverpool) (see this thread)
So, how do we go about estimating R? Here’s a post I wrote in January explaining R in relation to Covid-19 (which then didn’t have an official name) in relation to Covid-19 (which then didn’t have an official name)
To estimate R, we carry out surveys – which means you pick a representative group of people, either households or individuals, and test them repeatedly. There are two main surveys: ONS and REACT
ONS excludes student halls of residence, as ‘only private residential households, otherwise known as the target population in this bulletin, are included in the sample. People in hospitals, care homes and other institutional settings are not included’. This is confirmed here.
The REACT survey uses GP lists to generate its sample of people who are tested. But of course, new students are only just registering with their GPs, and it is unclear when the GP lists were pulled for the latest study (Round 5 of REACT-1, 18-26 Sep)
We know that halls of residence are a significant driver of transmission.
We may be systematically under-sampling from halls of residence and therefore systematically underestimating R.
The Wall Street Journal is reporting that “New York City on Wednesday will close public schools and nonessential businesses in parts of Brooklyn and Queens that have registered a week-long spike in coronavirus cases”
Let’s look at New York and then compare to a UK city, Liverpool.
Cases are high in some New York boroughs. Up to 216 cases per 100,000 per week. But school closures are also being implemented in areas with 89 cases per 100,000 (source: New York Times)
Let’s compare with Liverpool. Here is the latest @PHE_uk report. Liverpool has cases of 238 cases per 100,000 in a week. Which is slightly higher than the highest rate ZIP code in NYC.
But remember, Liverpool’s figures are for the whole local authority.
Let’s dig a little deeper into Liverpool. Here’s the map. We can see some areas with incidence in excess of 1200 cases per 100,000. That’s very high. And don’t forget this is detected cases. The number of cases will be much higher.
But how do we know that there hasn’t been enough testing? We look at positivity. Positivity is the number of people who test positive divided by the number of people tested. And this is what NYC uses to determine whether schools should be closed.
If an area of NYC has positivity greater than 3% – three in every 100 tests being positive – then schools close. What does positivity tell us? Whether enough tests are being performed.
“the World Health Organization recommended in May that the percent positive remain below 5% for at least two weeks before governments consider reopening.” (Johns Hopkins University)
So, given that positivity is set at a threshold of 3% for school closures in NYC and WHO suggest 5% before reopening, this begs the question – What is the positivity in Liverpool?
Just under 15%, according to the latest published data (PHE week 40 reporting). Which means that around 15% of all tests in Liverpool come back positive. That’s *very high*. And means not enough testing is being carried out. And this is a problem.
This is just an example of a city with large positivity. Extra testing capacity has been sent to Liverpool presumably due to students returning to universities there. This is not a Liverpool problem – it’s a national problem.