Ross Clark

There seems to be only one certainty with Covid-19: that every day we will be bombarded with fresh evidence and scientific opinion that is contradictory and leaves us a long, long way from understanding this disease. Just when it seemed that antibody tests were indicating infection rates of no more than 10 per cent in the worst-affected countries and no greater than 20 per cent in the worst-affected cities, along comes a study which points to vast numbers of infections. This morning, the public health agency in the Northern Italian city of Bergamo – the epicentre of the Italian outbreak in March – reports that a random sample of 9,965 residents from the worst-affected areas show the presence of antibodies in a remarkable 57 per cent of cases.

Are we going to see a dreaded second spike in coronavirus cases? The question has a new poignancy after a week of mass protests where all pretence at social distancing seems to have gone out of the window. Life is getting back to normal, employment is sharply on the rise again and markets are soaring. Most notably of all, the distressing scenes in New York hospitals have ended as the virus appears in sharp decline there. Nationally, across the US it is possible to detect a downwards trend in the number of new Covid-19 cases and deaths. The epidemic appears to have peaked in early April and tailed off since then – just as it has in Europe. But that isn’t the whole story. Drill down state by state and there is a very mixed picture.

The government has placed a lot of hope in its test and trace system, but even disregarding teething problems with the smartphone app and reports of some of the 25,000 contact tracers being left idle, is it even possible for it to achieve its objective? The problem with Covid-19 all along, and the reason it has managed to evade the efforts of containment which had worked with previous novel viruses such as SARS and avian flu, is the sheer number of people who seem to be infected but who show no symptoms. Some studies have shown that 80 percent of cases might fall into this category. Worse, there is plenty of evidence to suggest that these asymptomatic individuals are capable of passing the infection to others.

All through the Covid-19 pandemic we have been hampered by a lack of data on just how many people have had the disease. Given that several studies have indicated that as many as 80 per cent of people who are infected show no symptoms whatsoever, it is extremely difficult to estimate this crucial figure – which determines the mortality rate of Covid-19 and also how far away we might be from achieving a position of herd immunity. Today, however, comes some very substantial data. The Medical Research Council’s Biostatistics Unit has published estimates of infections derived from serological studies on samples collected from the NHS Blood Transfusion Service.  It estimates that between 4.9 million and 6.

Professor Neil Ferguson has been a little elusive of late – ever since he was forced to resign after he was revealed to have entertained his married lover at his home, thus breaking lockdown rules. But he did emerge from the woodwork this morning to give evidence to the House of Lords select committee on science and technology. In doing so he succeeded in walking into a fresh controversy. One of the first questions he was asked was by Conservative peer Viscount Ridley, who brought up (10:40) the subject of a Swedish study which sought to apply to Sweden Ferguson’s infamous mathematical model which forecast 250,000 deaths in Britain if the government continued with its mitigation strategy.

Sweden has received quite a kicking for its decision to avoid a lockdown: look at its death rate, critics say, which at 435 per million is several times that of neighbouring Denmark (99) and Norway (44). But there is another country that has taken the Swedish route which is rather harder to criticise.  In Japan, restaurants, shops, hair salons have remained open throughout and there have been no restrictions on personal movement. Moreover, in contrast to South Korea and Taiwan, there has been little testing – Japan has performed 2,300 tests per million residents, compared with 920,000 per million in South Korea (Britain, by the way, has performed 63,000 tests per million). Even Sweden, on 24,000 tests per million has outperformed Japan on that front.

Test, track and trace is an integral – and very expensive – part of the government’s plans for lifting lockdown and getting the country back to normal. The government is trying to hire 25,000 contract-tracers to augment an app-based system which seems mysteriously to have all-but vanished from its plans. But could there be a cheaper way of gaining advanced warning of infection in an area, allowing localised lockdowns to be imposed? Whatever happened to RNA levels in sewage was followed very closely three days later in hospital admissions A study led by Jordan Peccia at Yale University raises the possibility of an intriguing early warning system for Covid outbreaks.

It has been clear from the outset of the Covid-19 pandemic that there is a very steep age profile to its victims: with few children and teenagers experiencing serious symptoms while their grandparents suffer a high death toll. But what about the numbers of people infected? Two studies, in Britain and Sweden, appear to show that when it comes to infections, as opposed to deaths and hospitalisations, there is an inverse profile, with young people are contracting Covid-19 at a higher rate than the elderly. This week, Public Health England (PHE) announced initial results of the antibody tests which should help us solve the great unknown: just how many of us have had Covid-19, whether we experienced symptoms or not?

Could the Government be about to relax the two-metre rule for social distancing? On Wednesday morning, professor Robert Dingwall, a sociologist who sits on the New and Emerging Respiratory Virus Threats Advisory Group, questioned the rule, saying he had tried to trace the scientific justification for it but couldn’t. The evidence, he said, was ‘fragile’. Some countries, such as the US and Spain, have also set a distance of two metres but others, such as Australia, Germany and the Netherlands are content with 1.5 metres and others, such as Norway and Finland are happy with a single metre. The two-metre rule is going to be a huge impediment to relaxing lockdown. As an example, a standard train carriage in Britain is 2.8 metres wide.