Britain has changed course in the fight against Covid-19, after originally following an approach with significant scientific defects. Gary McLean, a New Zealand professor in molecular immunology and infectious diseases specialist at London Metropolitan University, explains.

More than 200,000 people are now laboratory-confirmed cases of Covid-19, across 157 countries. Tragically, almost 9,000 people have succumbed to the disease with the highest numbers seen in China, Italy, Iran and Spain. The pandemic originated in China but is now growing at the fastest rate in Europe, with several EU countries in lockdown. There are border closures, schools and services shut, large gatherings of people are  banned, sporting and cultural events are cancelled and there are severe restrictions on movement of people. These are unprecedented measures in peacetime.

The response to the outbreak has differed in Britain, partly because here it is some weeks behind in terms of the escalation rate of the outbreak and also because of its geographic isolation from the continent. The UK began by trying to contain the outbreak by isolating those who tested positive and asking anyone who had close contact with them to self-isolate, too.

In early March it was clear that this approach would not be sufficient and a week ago, on March 12, Boris Johnston announced the official beginning of what was called the “delay phase”. The aim of this strategy was to delay and flatten the outbreak peak until summer to allow the NHS to cope with the sheer numbers of acute cases and requirements for intensive care.

Measures included self-isolation of those with minor flu-like symptoms, limiting large gatherings, encouraging home working where possible but, until today, not closing schools. These approaches were largely based on questionable epidemiologic modelling of the outbreak and were heavily criticised by experts both within the UK and overseas.

The government’s chief scientific advisor for England Sir Patrick Vallance countered, stating:

• That the virus appears to spread mostly in smaller group settings and that banning large group events would have little effect.
• That establishing herd immunity in the population would protect the most vulnerable in the population.
• That they could put measures in place to stop the epidemic within four months, but this would risk a second wave of the outbreak.
• That the virus is expected to become endemic and cause seasonal outbreaks.
• That he would follow the scientific evidence and modify the approaches as required.

Unfortunately, in several ways that approach is not supported by the scientific evidence. Establishing herd immunity depends on several factors such as the reproductive rate of the virus (average number of people infected from one infected individual) and the generation of protective immunity following infection. None of these are known or established for SARS-CoV-2, the virus which causes Covid-19, or indeed for other coronavirus infections, including SARS from 2003.

What is more, expecting the virus to become endemic – permanently established – is without precedent. SARS didn’t become endemic and neither has another recent coronavirus outbreak, MERS. Therefore, there is no scientific evidence to suggest tight control measures would result in a second wave of Covid-19 and seasonal epidemics thereafter. While the British government’s original approach was designed to manage the virus’s spread and not to overwhelm the health services, updated epidemiological modelling suggested that a daunting 250,000 deaths should still be expected.

And so on March 16, Johnson’s government announced it was ramping up control measures as the exponential phase of virus spread approached. Fortunately, being three to four weeks behind Italy’s outbreak curve means the UK can learn quickly from the situation in that country, where the virus’s spread is out of control and the health system is currently under severe stress. In Italy, the entire country has been under enforced lockdown for over a week already and intensive care physicians are having to make decisions on which patients to save and which are sadly beyond possible care.

The measures recently taken by the British government, while strict, are still a long way from what is enforced in Italy. Here in the UK, large gatherings are banned, people are told to work from home where possible, anyone with symptoms must self-isolate for seven days, and in households with symptoms the entire group must stop non-essential contact with others – especially those over 70, those with underlying health conditions and pregnant women – for 14 days.

In the past few hours it has been announced that schools will close. This measure was delayed due to worries about the knock-on effect of losing key workers required to mind children. Pubs, clubs, restaurants and theatres are now closed. The London Underground remains open but is running with a reduced service. The aim of these measures is still to reduce the epidemic’s peak and lessen the pressure on the National Health Service, but it seems inevitable that further, more draconian measures will be introduced as the epidemic worsens.

It now appears that the approach of the UK government is to stagger these control measures without alarming the general public and apply them at what they consider to be the most appropriate time to control the spread of the virus.

Many business owners will be under immense pressure and working parents will face difficulties by not having childcare options available now that schools are closing. The feeling here is that this epidemic is going to last some time and that the government may not have done enough, and what they did do was not done quickly enough. However, life in London is largely business as usual, and it is not yet clear that the public fully appreciates the serious nature of this epidemic.

Ultimately, even if the virus is suppressed with necessary control measures, there is a risk that as soon as those measures are removed the virus returns with a vengeance. An option proposed here is to go through cycles of lifting and reapplying the controls, using the demand on Intensive Care Units as a guide. One thing is for sure in these difficult times: there will be close attention paid to China and its approach in lifting restrictions.