London School of Hygiene & Tropical Medicine

The coronavirus pandemic is unprecedented. Potential strategies to stop the spread of COVID-19 need to be discussed and researched. A strategy proposed by Professor Julian Peto of LSHTM that has gained traction in the media recently is to test everyone in the UK for COVID-19 once a week. Broken down, that is ten 10 million PCR tests a day. Is this a wise strategy and is it possible?

I respect my colleague's academic freedom to question established thinking, but the views put forward by Professor Peto are not shared either by myself nor by a number of other expert scientists working on COVID-19 at LSHTM. There are both practical and scientific flaws in the strategy proposed.

While there is indeed the potential to re-purpose some PCR machines in the UK to test for COVID-19, this is far from a simple solution. All the professional organisations and laboratory scientists are already working as hard as they can to increase testing numbers in the UK. But the UK is not alone: this is a truly global pandemic and a large number of countries, just like the UK, are trying to increase the number of people tested. This means worldwide shortages in the testing kits and reagents required. It is not simply a matter or making or buying more.

No country has managed to achieve anything approaching the level of testing being proposed. We have absolutely no idea how testing tor 10 million people per day in the UK could be implemented. Nothing on that scale has ever been attempted.

In addition to the practical barriers, there is no scientific evidence to support the assertion that such a strategy would control spread of coronavirus. Viral circulation and infection is a fast-moving, dynamic process. There would inevitably be a lag in turn-around of test results, and by the time results are received the whole picture could have already changed, and many secondary infections have occurred. A PCR test for the presence of virus undertaken each week would not guarantee that people are free of infection between testing. To suggest that everyone testing negative would be able to “go about their business” would lead to increased spread of the virus and increase the number of cases and deaths, and would lengthen the epidemic. 

Scientists have the right to raise legitimate debate, but what we need to control this epidemic are practical, scientifically-driven strategies that are based on the best available evidence.

The government is committed to increase testing for COVID-19 as part of its overall strategy. But testing alone, even on a huge scale, will not control the spread of this virus. The country is united in a national effort to minimise the effects of this epidemic. Because of collective action - staying at home and maintaining physical distancing – we are beginning to see that spread of this virus may be slowing. What we need now is the continued commitment of the whole population to beating this infection, protecting vulnerable people and reducing the pressures on the NHS.