#covid-19 Scientists working at the high security laboratories at Porton Down are testing for antibodies blood samples from across Britain. They hold the key to exit from lockdown telegraph.co.uk/global-health/…
At the Centre for Applied Microbiology and Research, housed within the high security Defence Science and Technology Laboratory at Porton Down near Salisbury, scientists are pouring over 800 blood samples taken from a representative sample of the English population. 
They are conducting tests today which, more than any others you may have read about, will decide the shape and timing of (not only) UK’s coronavirus exit strategy. Perhaps, just perhaps, they will provide the key to the door that is lockdown.
If the tests work — virologists are confident they will — they will provide the answers to the most important unknowns about Covid-19: how many have already had the virus? How common are asymptomatic carriers? How much immunity, if any, do we acquire after surviving an infection?
The answers to these questions are what every govt is rushing to unearth. They are the gold dust of the pandemic. They will inform not just exit through a much more precise modelling of the pandemic’s trajectory, but the best approach to treatments and vaccines.
They're conducted behind the high security fences of Porton Down. “This sort of study is absolutely vital because we are so uncertain about the level of infection in the population”, said Mark Woolhouse Professor of Infectious Disease Epidemiology at the University of Edinburgh.
“As things stand we could be out by a factor or 10 or even 100. If work like this gives us even a rough pointer initially it would be hugely valuable”.
The work at Porton Down is understood to have been underway **since January**.
The work at Porton Down is understood to have been underway **since January**.
Moreover, it plays to our skill set as a nation, based as it is on high-end science rather than the more mundane — but crucially important business — of high volume production.
Experts say the first two months were spent validating high tech "assays" for reliably identifying coronavirus antibodies and designing a robust longitudinal blood sampling study. The first 800 blood samples were delivered to the laboratory in late February.
"We are expanding this programme during April so that we have the potential to test around 5,000 samples per week", said the DHSC. "We will also roll out a national mass population sample over the coming months. Aim to enrol 16,000-20,000 people who will undergo repeat testing".
So far media attention has been focused on swab tests for the virus and cheap home antibody tests to tell people if they have already been infected. While the swab tests are reasonably precise, the home antibody testing kits are currently woefully inaccurate.
The "assays" run at Porton Down are excellent. “The tools, the expertise are there. You can be confident at Porton Down they've access to sensitive assays that can accurately determine antibody levels in patients’ blood,” Zania Stamataki, viral immunology University of Birmingham
These Porton Down assays are those against which the commercial antibody tests the government has taken options on are being validated.
First aim at Porton Down is to establish how widely the virus has spread. Current models (like the Imperial College model) assume the spread it's fairly modest (3-4% of the population). It could be a lot higher. This is the crucial variable to predict the course of the epidemic.
“Data in the coming weeks will enable estimation... with greater precision,” the team at Imperial College London — whose work underpins the UK’s lockdown — admit in a report dated March 30.
Prof David Heymann, infectious diseases expert at the London School of Hygiene and Tropical Medicine, added: “they will provide the level of people infected: crucial to inform the modelling. Modelers use best possible data at the time, but this changes rapidly.”
As a political pollster can take a small representative sample of the population to establish voting intentions with accuracy, scientists at Porton Down hope to pin down a figure for the spread from the initial 800 blood samples, improving on as they test more samples over time.
The study will also provide data on the vexed question of the number of the non-symptomatic. This again is vital information for those devising Britain’s exit strategy. Current estimates for non-symptomatic carriers vary hugely.
Karol Sikora (prof of medicine at the University of Buckingham, former director of the WHO): “In studies on cruise ships and small countries, where they’ve tested just about everyone, some 50% of people infected have no symptoms whatsoever, not even a sore throat or cough."
“That number could mean 20%-30% of the population have been infected in the UK, which would have huge implications for our strategy - especially around herd immunity and NHS capacity. That information really is vital.”
Plus, the work at Porton Down will, in six months to a year, show whether or not the antibodies produced after contracting Covid-19 give immunity and how long it lasts. Currently, science is completely in the dark about this, the single most important question of all.
“The existence of antibodies means you will have some protection but this is not necessarily the case,” said Dr Stamataki. “We do know antibodies from existing coronavirus can last for 1 year or more. But this is a novel virus”
The Porton Down research will establish this by means of a longitudinal study whereby the participants would have their blood checked for antibodies regularly over time to see how long they last. Animal studies will be run consecutively to test their protective potency.
“One can’t overstate the importance of establishing the strength of any immunity”, said Dr Stamataki. “Even if it lasts for just a year it would give many of us the chance to return to normality.”
The work at Porton Down puts into perspective the trouble governments around the world are having with home antibody tests. Even if these tests prove accurate they are next to useless unless it is known that the antibodies they test for provide protection.
