Bad vibrations: Quantum tunnelling in the context of SARS-CoV-2 infection*

Quantum biology, the application of quantum theory to the study of living systems, is often focused on charge transfer. The first evidence for quantum effects in enzymes focused on tunnelling and a great deal of effort has gone into investigating the movement of energy and charge in photosynthesis. Environment assisted tunnelling has also been suggested to be the mechanism by which olfaction works. We consider whether the progress made in these contexts might be applied to the context of SARS-CoV-2 infection. We propose that quantum biology might offer essential new insights into the problem, especially with regards to the important first step of virus-host invasion. ACE2 enzymes are implicated in the invasion of host cells by the SARS-CoV-2 virus. Receptors such as olfactory receptors also appear to be disrupted by COVID-19. Building on these observations we investigate the evidence that quantum tunnelling might be important in the context of infection with SARS-CoV-2. We illustrate this with a simple open quantum systems model relating the vibronic mode of the viral spike protein to the likelihood of charge transfer in an idealised receptor. Our results demonstrate distinct parameter regimes in which spike protein vibronic mode enhances electron transport.