• Government policy response to Covid-19 is severely hindered by the lack of real-time data on what % of the population has the virus already.
• The data available to policymakers currently is clearly insufficient. Daily coronavirus death counts get the most media attention, but this is a highly delayed indicator, as there is an estimated 2 – 8 week lag between contracting the infection and death.
• The media also tracks the number of people who have tested positive for coronavirus. This figure is entirely useless, as most countries now only test patients with severe symptoms, so this potentially underestimates the true number of coronavirus cases in the population by several orders of magnitude.
• It was eye-opening to read an interview with Prof Neil Ferguson (author of the influential Imperial College study that partly led to implementing the lockdown). He guesstimates that 3-5% of the UK population might have the virus currently, rising to “no more than 10%” in a week’s time.
• Why are we guesstimating these figures? This is literally the most important data point in informing government response to the virus.

Why we need an up to date measure of how many people have the virus currently

• To understand how effective the lockdown is in slowing down transmission
  • We would find out when the lockdown gets us over the peak. People are waiting for a fall in the daily death count, but this will only starts weeks after the actual peak. Keep in mind that each week under lockdown causes untold economic damage and hundreds of thousands of job losses.
  • We would find out if the current “weak points” in the lockdown render the whole thing pointless – people can still get infected in crowded supermarkets or on public transport. The inexcusable lack of protective equipment in the healthcare system exposes the 500,000 frontline NHS staff to the risk of infection.
  • We would find out if lifting certain elements of the lockdown (e.g. re-opening more shops or construction sites) increases transmission. If the increase was large, we could quickly tighten the lockdown again.
• To prepare for near-term demand on hospitals
  • People who require hospitalisation for Covid-19 typically get worse one week after contracting the virus. Having a real-time, region-by-region picture of active infections would give some advance warning to hospitals to better prepare for patient inflow.
• It would immensely help inform the exit strategy from the lockdown
  • Some think we should try to contain & eradicate the virus by conducting a large number of tests across the population. Others think the virus is too widely spread by now to eradicate it and see eventual herd immunity as the end result.
  • Clearly, both camps are just guessing if we do not know what percentage of the population is already infected. If a significant share of the population has already been infected, then herd immunity is not too far off. If infections are limited to a few percentage points, then eradication seems more viable.
• To understand how deadly the virus actually is, and how mortality rates break down by age group and other risk factors
  • Experts typically assume that Covid-19’s mortality rate is around 1% and that mortality rates get radically worse for people aged over 50. This is generally based on data out of China. There is no guarantee that the virus works exactly the same way elsewhere, so we need to be able to calculate our own mortality rates to inform our policy response.

How to do random testing

• It’s fairly simple and requires only limited resources.
• A random sample of 1,000 people repeated every other day would provide meaningful real time data on the spread of the virus. This would be far more useful than anything we have today.
  • The UK’s is testing 10,000-15,000 people each day (which is pathetic in comparison to other countries) and aims to scale up to 100,000 per day. Random testing would use up only a small share of testing capacity.

Is anyone doing this already?

• Iceland is the only country in the world that has done random testing.
  • Out of a random sample of 2,300 individuals, 13 (0.6%) have tested positive.
  • It is likely that this percentage could be much larger in other countries. Iceland is not as plugged into global travel (especially at winter time) and its coronavirus response to date has been excellent.
• Finland and Norway following Iceland’s lead and commissioning random tests. There appears to be some interest from various US states as well.
• It is baffling why the UK is yet again so far behind the curve.