King Canute and the Cult of Zero Infection

King Canute is a familiar figure in the myths that the English construct around their history. While there was a real monarch, Cnut, who ruled from 1016 until 1035, the story for which he is best known was probably invented in the 12th century. This describes him setting up a throne on a beach and commanding the incoming tide to cease its advance. The tale is often represented as a critique of the foolishness or arrogance of those in power, who think that they can bend nature to their will. In its earliest form, however, it is clear that the moral is intended to be one of the king’s humility, his own recognition that, however, much he is flattered by his courtiers, his power has inescapable limits. Even a monarch cannot countermand the fundamentals of the universe.

This is a lesson that some still struggle with in considering the goals of clinical medicine and public health. If they only had enough money, power and time, biomedical scientists could eliminate infection and, at least by implication, allow humans to live forever. Philosophers, ethicists and theologians have long pointed to the dangers of this program, of living life in a permanent struggle to avoid our unavoidable death. It is also inconsistent with the fundamentals of evolution.

Popular versions of Darwinian thought are fond of the metaphor of the ‘tree of life’, evolution as a linear process towards the present, where various dead ends become extinct as the best of all possible worlds is approached. This goal-directed version of evolution has had a major, and largely pernicious, influence on both natural and social sciences over the last century.

Darwin, himself, though, preferred a later metaphor, the ‘tangled bank.’ As he walked the country lanes around his home in Kent, he observed how their hedgerows changed with the seasons. Each species was in constant competition with all the others for light and space. These pressures distributed the plants across the year as each established a niche that made possible its reproduction and survival. But this result was transient. Adjacent species might evolve in ways that crowded out the existing tenants. New seeds might be introduced and compete with those already present. Variations in weather from one year to the next changed the environmental conditions.

The order Darwin observed was precarious and quite different from the planned order of his garden. There is no ‘best world’ to be attained, just the one we have for the moment, which is merely a temporary point of stability within an infinity of change. This version of evolutionary thought was taken into sociology by the leading figures of the Chicago School in the 1920s and 1930s.

It is increasingly accepted that Zero-Covid — the eradication of the SARS-Cov-2 virus — was never achievable. However, this position has mutated, in a way evolutionary theory would recognize, into what we might call ‘Zero-Infection.’ If one pathway is blocked, the argument could shift to another, which might bring resources and rewards to its promoters. If we cannot eradicate this virus, then we should vaccinate the entire planet, regardless of the risk/benefit or opportunity costs, and maintain NPIs of uncertain value because these might mitigate a range of respiratory infections. Small children, for example, must be vaccinated because Covid is an infection, not because healthy infants are at risk of serious illness or death.

What, though, does Zero Infection actually achieve? We do not have to look far to find out. Human interventions constitute a selection pressure on other species. If they are not to go extinct, selection must favor some mutation that sustains their own reproduction and survival. One of the biggest threats to the health regime that humans currently enjoy is antibiotic resistance. The pursuit of zero infection from bacteria by the use of antibiotic treatments has created conditions for the evolution of bacteria selected for their resistance. The same logic applies just as much to viruses. Some commentators have, for example, suggested that the current threat from monkeypox reflects human success in eradicating smallpox and removing a competitor from the same ecological space. It is not a fringe view in immunology to argue that a certain level of exposure to infection is important for the development of the human immune system. Interventions that disrupt a particular equilibrium have uncertain systemic consequences.

As sociologists, we are constantly reminded of the fragility of social order and the work that goes into its creation and maintenance. If zero infection disrupts a biological order, its pursuit also disrupts a societal order. The fear of face-to-face human interaction takes us toward Thomas Hobbes’s nightmare thought experiment of a world of solitary individuals leading impoverished and insecure lives.

The humility of King Canute in the face of nature is worth recalling as a check on the enthusiasm for zero-infection. It is a fine-sounding slogan but do we really want to live in a society where everything else is sacrificed to this goal? ‘Infection’ is a human moral judgment on some of the viruses and bacteria that co-exist with us, as they have done throughout the existence of our species. Nature does not make these judgments. Frankly, nature does not care whether our species survives or not, if it gets out-competed by some other species.

Humans are buffered from the extreme consequences of evolutionary competition by their ability to modify their environment and its selection pressures. Where we can blunt the impact of the bacteria and viruses that challenge our well-being and existence, we should certainly consider doing so. But the emphasis must be on ‘consider’, with a high degree of confidence that the outcomes will be what we hope for.

Let us not forget that sociologists pretty much identified the phenomenon of unanticipated consequences…Be careful what the Zero-Infection cult is wishing for.