coronavirus
Many people still struggle to accept the idea that lockdowns don't have any appreciable impact on Covid cases and deaths. After all, it's obvious, isn't it, that keeping people apart will stop the virus spreading?

Tom Harwood, formerly of Guido Fawkes now of GB News, tweeted a typically incredulous response to the idea: "Cannot understand how some can claim 'lockdowns don't work' with a straight face. As if stopping people from mixing wouldn't hit transmission? Sure argue the cost is too high, imposition on liberty too extreme, just don't invent a fairytale denying the basics of germ theory."


Even some die-hard lockdown sceptics will say that lockdowns work, in the sense of suppressing transmission for a time, but they just delay the inevitable so are pointlessly costly.

The models churned out by university academics and relied on by the Government to set policy all assume lockdown restrictions work, and even claim to quantify how much impact each intervention makes.

But what does the data say? What do the studies show that actually look at the evidence rather than just making a priori assumptions about how things "must surely" be?

There have been at least seven peer-reviewed studies which look at the question of lockdowns from a data point of view, and all of them come to the same basic conclusion: lockdowns do not have a statistically significant relationship with Covid cases or deaths. Here is a list of them with a key quote for ease of reference. Many of these studies attribute a large part of the drop in infections and deaths to the voluntary measures introduced prior to the legally-enforced restrictions. However, this is typically introduced as an assumption with no robust evidence provided in support of it, and with no consideration of the other possible reasons that infections might have fallen, such as seasonality or growing population immunity. On the rare occasion that rigorous analysis is applied to this question as well, as with Savaris et al in their article in Nature looking at whether people staying at home (measured using mobility data) is associated with Covid deaths, the finding is similarly negative. Voluntary measures make little difference either.

This may seem to defy "the basics of germ theory", as Mr Harwood put it. But it doesn't, it just means we need to understand better how the virus is getting round.

First of all, much of the spread, particularly that which leads to serious disease and death, occurs in hospitals and care homes. Forty per cent of Covid deaths in England and Wales in the spring were care homeresidents, while Public Health Scotland found that between half and two thirds of serious infections were picked up in hospital. Between these and transmission in private homes, this accounts for much of it.

In terms of community transmission, even during a stringent lockdown such as in the UK this winter, around half the workforce are travelling to work, while only around a third work exclusively from home. Add to that that many people still use supermarkets and other shops, and many children still attend school (even where the schools are only open for key workers' children), and that's a lot of social interaction. We also know from a major UK survey that less than half of people with Covid symptoms fully self-isolate, giving reasons such as going to work, going to the shops or regarding the symptoms as mild. This means we don't need to resort to unsubstantiated ideas of asymptomatic infection being a major driver of transmission (which is unsupported by evidence, since, as with other similar viruses, asymptomatic infection is barely infectious and contributes very little to spread) to explain ongoing community transmission.

The idea that locking down and keeping people apart will stop a virus spreading may be seductively intuitive. But intuitive ideas can be wrong. The job of science is to examine ideas and test them with evidence to see if they are more than just speculation. And the science here is clear. Lockdowns do not control the coronavirus.