There is an angry, heated row raging among scientists about how best to tackle Covid-19. Given all the variables, we shouldn't be surprisedby Philip Ball / March 16, 2020 / Leave a comment
Dissent and dispute are a normal part of science. If you ask randomly selected high-energy physicists where we should be looking for a theory of quantum gravity, you can be sure that whatever answer they give will be challenged by some of their peers. If you ask geneticists to what degree genes determine social structures and human variation, or neuroscientists how the brain works, likewise none will give an answer that others won’t denounce.
In normal times the rest of us can watch these debates with interest, amusement or mild confusion. With strategies for tackling the coronavirus pandemic, we don’t have that luxury. For some of us—it is actually rather terrifying to write this—which experts are right and which are wrong will determine whether we, or our loved ones, will live or die.
To keep a little proportion on that stark truth: it was ever thus, to some degree, in biomedical science. In the early days of AIDS research, for example, there were genuine scientific disagreements about causes and treatments (even if these were outrageously abused by contrarians with agendas), and there too the consequences made the difference between life and death. It’s only because the HIV epidemic has moved more slowly that we tend to overlook how lethal it became before scientists worked out not only ways to slow and arrest the problem with drugs (there is still no vaccine) but how to most effectively implement appropriate social measures to check the spread. Around 35 million have died globally since the AIDs epidemic began, and even in 2018 around a quarter of a million died from AIDS-related illness.
While, therefore, we can be dismayed at the angry row that is raging among scientists about how best to tackle the coronavirus, we shouldn’t be surprised. This is an immensely difficult question, and prediction is inherently uncertain, not only because of gaps in our biological understanding of the virus and its effects but also because so much depends on the vagaries of human behaviour: how we respond to advice, nudges and directives, and for how long. And while there are always lessons to be learnt from previous recent epidemics—for example, bird flu, SARS (to which this coronavirus is related) and Ebola—there can never be an off-the-shelf solution given that the important variables, such as degree of infectiousness and mortality rate, differ for every virus.
Let’s not forget what sound science has given us already, though. While there are serious questions to be asked about the policy of testing people (or not) for infection, the fact that there is a test at all is extraordinary given that the virus wasn’t even known until the end of December. (Chinese scientists published the genome sequence in the leading science journal Nature last week, although they released their data in early January and this has been available online since early February.)
And we shouldn’t doubt for a moment both that the government’s senior advisers—the chief medical officer Chris Whitty, himself a specialist in the epidemiology of infectious disease, and the chief scientific adviser Patrick Vallance—are both hugely experienced and knowledgeable, and will be giving the advice that they think is most likely to minimise the worst impacts of the pandemic in the UK. It is perilously easy, particularly if you don’t like this government (full disclosure: I do not) to want to believe conspiracy theories or cynical interpretations of their choices. But so far Boris Johnson seems to be deferring to his top scientists and not engaging in political brinkmanship. He looks thoroughly miserable at having such a frightening responsibility descend on him when he must have been looking forward to a year of revelling in his election victory, but he has so far managed to curb his bombastic, belligerent, crowd-pleasing style and to respond with gravity and dignity. (The same, alas, cannot be said for Donald Trump.)
Unpacking “herd immunity”
But this does not mean these scientists are right. The course they have chosen is very risky, not least because it seems to depend on an ability to nudge the behaviour of the population with enough accuracy to guide the spread of the virus along the track they have chosen. One can see the logic to it: if the best judgement of the psychologists is that extreme containment is impossible to sustain short of imposing something like martial law, a second wave of spreading seems very likely once the measures are relaxed. Such waves of infection have been seen in other pandemics—notably in the 1918 Spanish flu—and they could potentially result in more illness and death overall.
It’s important to recognize too that the strategy does not, as some have said, aim to make at least 60 per cent of us get Covid-19—the level at which the much-vaunted “herd immunity” is thought to set in. Rather, it assumes that it will be more or less impossible to avoid that level of infection before any vaccine is available. The question then is how best to manage it so that the health services are not overwhelmed. The mortality rate may depend not so much on how many people get infected but who they are, and how readily those who need emergency treatment can get it.
But those who say we must keep quiet and trust the experts are wrong. Partly this is because there are important, valid questions to be asked, and we need and deserve answers. And partly it is because expert opinion here depends on the expert. It is understandable that people should wonder why the British science advisers have come to such different conclusions from experts in other countries, based on the same data. In particular, what they are advocating seems in many respects to fly in the face of the recommendations of the World Health Organisation—which has explicitly questioned the UK strategy.
Take testing. Whitty has said “It is no longer necessary for us to identify every case and we will move from having testing mainly done in homes and outpatients and walk-in centres, to a situation where people who are remaining at home do not need testing.” But the WHO recommends testing to try to identify every person infected with the virus. Extensive testing even of marginal cases seems to have been vital to South Korea’s containment plan: it had tested around a quarter of a million people by the end of last week, ten times as many as the UK. If the government’s aim is to manage infection rationally, it’s hard to see how that can work without accurate data on its extent. My own family is currently in self-isolation because of recent contact with another family who have the coronavirus symptoms but may or may not have the disease. Without that certainty, many in our position will understandably (but wrongly) choose to carry on as normal.
Expert against expert
What is most alarming is that even some very basic matters are provoking argument among experts. Harvard epidemiologist William Hanage (who trained in the UK) says that, while it is valid to invoke herd immunity when deciding target levels for vaccine programmes, it’s a different matter to make it part of a strategy in which people will get sick and die. When he first heard of the plan, Hanage says that he “assumed that [the] reports… were satire—an example of the wry humour for which the country is famed. But they are all too real.” He says too that the risk of a second wave of infection after robust containment policies are relaxed can’t just be assumed: it can happen for flu, but this is not flu. We could see if there is such a danger from what happens next in China—but for now, he says, all efforts should be directed at containment. Hanage and colleagues have estimated (conservatively, they say) that the current UK strategy could leave around 8,500 people aged 20-40 needing an intensive care unit bed at the peak of the epidemic—more than twice as many beds as currently exist.
Some of the disagreements among experts have arisen because no one is an expert in every aspect of this problem. The British Society for Immunology has released an open letter, signed by its president Arne Akbar of University College London, saying that we don’t know enough about immunity to the coronavirus anyway, so the government should be focusing on containment. “For example, we don’t yet know if this novel virus will induce long-term immunity in those affected as other related viruses do not,” the letter says. “Therefore, it would be prudent to prevent infection in the first place.”
Some of the strongest criticisms of the government policy have come from Richard Horton, editor of leading medical journal the Lancet, who has said that “The UK is on the edge of an avoidable calamity. In addition to deaths preventable by more aggressive government action, it will be health workers who absorb the brunt of government complacency… What is happening in Italy is real and taking place now. Our government is not preparing us for that reality. We need immediate and assertive social distancing and closure policies.”
And more than 200 scientists have signed an open letter expressing deep concern about the UK approach. “By putting in place social distancing measures now, the growth can be slowed down dramatically, and thousands of lives can be spared,” they say. “We consider the social distancing measures taken as of today as insufficient, and we believe that additional and more restrictive measures should be taken immediately, as it is already happening in other countries across the world.”
In response, one researcher who has worked on global health issues related to viruses such as hepatitis A virus dismissed the letter, saying she had never heard of any of the signatories. But this is because they come largely from the community that studies complex systems, including the mathematics of spreading on social networks (among them are Steven Strogatz of Cornell and Albert-Laszlo Barabasi of Northeastern University, world leaders in this field). Both of these communities have important perspectives on an issue like this, so it is shocking and alarming to see that they apparently do not know each other but are instead working within academic siloes. That has to change, as soon as possible.
The importance of communication
This, then, is one of the vital lessons from the argument. Scientists of all persuasions (including sociologists) have been weighing in, often with important considerations but also often with an assumption that they have a unique grasp of the key facts. Even given the fact that this is a tremendously difficult problem involving many key unknowns, it is little short of deplorable that “experts” seem to have such fundamentally different ideas and such a lack of dialogue.
Commendably, Vallance has said that the models and calculations on which the government’s strategy is based will be released so that others can assess them. It’s ultimately a good thing too that the government was prepared to shift, within a day or so, its position on banning large gatherings. Yes, that makes you wonder how shaky the models were in the first place, but if new data or developments demand a change of course, the stakes are too high to worry about the political loss of face typically associated with U-turns. Science is built on U-turns.
The worry, though, is that such moves will be too little, too late. Judging from the current trend in UK deaths, another revision of the plan might be necessary very soon. At any rate, keeping people clearly and regularly informed is going to be a vital part of any strategy. So far there is plenty of room for improvement in that regard. In the absence of strong containment measures, people are likely to get the idea that they can carry on as normal—witness the ongoing public events and mass gatherings over the weekend. School closures present many complications, but it’s hard to see any good reason why theatres, cinemas and pubs are still open for business.
It is no wonder people are confused. When Devi Sridhar, an expert on global health at Edinburgh University, wrote in the Observer that “The [government’s] plan… is to work towards “herd immunity’,” she seemed to be reiterating standard wisdom. But what, then, to make of Health Secretary Matt Hancock’s comment over the weekend that “Herd immunity is not a part of [the plan]. That is a scientific concept, not a goal or a strategy”? It’s bad enough that Hancock’s article first appeared as a paywalled op-ed in the Sunday Telegraph. But even I don’t really know what he was trying to say here.
The latest decision by Downing Street to hold daily televised press briefings is, however, a good one. Already they have some serious questions to answer.