Porous surfaces: stability and recovery of coronaviruses

The role of indirect contact in the transmission of SARS-CoV-2 is not clear. SARS-CoV-2 persists on dry surfaces for hours to days; published studies have largely focused on hard surfaces with less research being conducted on different porous surfaces, such as textiles. Understanding the potential risks of indirect transmission of COVID-19 is useful for settings where there is close contact with textiles, including healthcare, manufacturing and retail environments. This article aims to review current research on porous surfaces in relation to their potential as fomites of coronaviruses compared to non-porous surfaces. Current methodologies for assessing the stability and recovery of coronaviruses from surfaces are also explored. Coronaviruses are often less stable on porous surfaces than non-porous surfaces, for example, SARS-CoV-2 persists for 0.5 h–5 days on paper and 3–21 days on plastic; however, stability is dependent on the type of surface. In particular, the surface properties of textiles differ widely depending on their construction, leading to variation in the stability of coronaviruses, with longer persistence on more hydrophobic materials such as polyester (1–3 days) compared to highly absorbent cotton (2 h–4 days). These findings should be considered where there is close contact with potentially contaminated textiles.

Editorial: theme issue on coronavirus and surfaces

Since the publication of the headline review on ‘Surface interactions and viability of coronaviruses' in Journal of the Royal Society Interface in January 2021 ( https://doi.org/10.1098/rsif.2020.0798 ), it has been my earnest desire to focus the minds of the scientific community on the role played by surfaces in the spread of COVID-19, especially the input physical sciences and engineering can impart to decelerate the spread of this disease worldwide. In fact, fig. 4 of the above-mentioned review clearly illustrated how persistence and viability of different coronavirus strains were dependent on widely used material surfaces. I thought the best way to achieve this goal on this rather complex and novel scientific issue was to put together a concise theme issue in Interface Focus where we bring together the opinions of a few internationally leading researchers on this important topic to collectively reduce the burden of COVID-19. Coronavirus and surfaces, the theme of this issue, is of utmost importance to many commercially significant industries such as packaging, textiles and metal forming. As the virus mutates and alters its anchoring and survival capabilities, this theme on coronavirus and surfaces will become more important, so we need to focus on this theme scientifically and methodically, with utmost urgency.

SARS-CoV-2–host cell surface interactions and potential antiviral therapies

In this review, we reveal the latest developments at the interface between SARS-CoV-2 and the host cell surface. In particular, we evaluate the current and potential mechanisms of binding, fusion and the conformational changes of the spike (S) protein to host cell surface receptors, especially the human angiotensin-converting enzyme 2 (ACE2) receptor. For instance, upon the initial attachment, the receptor binding domain of the S protein forms primarily hydrogen bonds with the protease domain of ACE2 resulting in conformational changes within the secondary structure. These surface interactions are of paramount importance and have been therapeutically exploited for antiviral design, such as monoclonal antibodies. Additionally, we provide an insight into novel therapies that target viral non-structural proteins, such as viral RNA polymerase. An example of which is remdesivir which has now been approved for use in COVID-19 patients by the US Food and Drug Administration. Establishing further understanding of the molecular details at the cell surface will undoubtably aid the development of more efficacious and selectively targeted therapies to reduce the burden of COVID-19.

Contact transmission of SARS-CoV-2 on fomite surfaces: surface survival and risk reduction

There is an unprecedented concern regarding the viral strain SARS-CoV-2 and especially its respiratory disease more commonly known as COVID-19. SARS-CoV-2 virus has the ability to survive on different surfaces for extended periods, ranging from days up to months. The new infectious properties of SARS-CoV-2 vary depending on the properties of fomite surfaces. In this review, we summarize the risk factors involved in the indirect transmission pathways of SARS-CoV-2 strains on fomite surfaces. The main mode of indirect transmission is the contamination of porous and non-porous inanimate surfaces such as textile surfaces that include clothes and most importantly personal protective equipment like personal protective equipment kits, masks, etc. In the second part of the review, we highlight materials and processes that can actively reduce the SARS-CoV-2 surface contamination pattern and the associated transmission routes. The review also focuses on some general methodologies for designing advanced and effective antiviral surfaces by physical and chemical modifications, viral inhibitors, etc.

Potential therapeutic approaches for targeted inhibition of inflammatory cytokines following COVID-19 infection-induced cytokine storm

Coronavirus disease 2019 (COVID-19) is a deadly respiratory disease caused by severe acute respiratory syndrome coronavirus 2, which has caused a global pandemic since early 2020 and severely threatened people's livelihoods and health. Patients with pre-diagnosed conditions admitted to hospital often develop complications leading to mortality due to acute respiratory distress syndrome (ARDS) and associated multiorgan failure and blood clots. ARDS is associated with a cytokine storm. Cytokine storms arise due to elevated levels of circulating cytokines and are associated with infections. Targeting various pro-inflammatory cytokines in a specific manner can result in a potent therapeutic approach with minimal host collateral damage. Immunoregulatory therapies are now of interest in order to regulate the cytokine storm, and this review will summarize and discuss advances in targeted therapies against cytokine storms induced by COVID-19.

Characteristics of respiratory microdroplet nuclei on common substrates

To evaluate the role of common substrates in the transmission of respiratory viruses, in particular SARS-CoV-2, uniformly distributed microdroplets (approx. 10 µm diameter) of artificial saliva were generated using an advanced inkjet printing technology to replicate the aerosol droplets and subsequently deposited on five substrates, including glass, polytetrafluoroethylene, stainless steel, acrylonitrile butadiene styrene and melamine. The droplets were found to evaporate within a short timeframe (less than 3 s), which is consistent with previous reports concerning the drying kinetics of picolitre droplets. Using fluorescence microscopy and atomic force microscopy, we found that the surface deposited microdroplet nuclei present two distinctive morphological features as the result of their drying mode, which is controlled by both interfacial energy and surface roughness. Nanomechanical measurements confirm that the nuclei deposited on all substrates possess similar surface adhesion (approx. 20 nN) and Young's modulus (approx. 4 MPa), supporting the proposed core–shell structure of the nuclei. We suggest that appropriate antiviral surface strategies, e.g. functionalization, chemical deposition, could be developed to modulate the evaporation process of microdroplet nuclei and subsequently mitigate the possible surface viability and transmissibility of respiratory virus.

Functionalized non-woven surfaces for combating the spread of the COVID-19 pandemic

The worldwide outbreak of SARS-CoV-2 infection has necessitated mandatory use of face masks, personal protective equipment and intake of a healthy diet for immunity boosting. As per WHO's recommendation, continuous use of masks has been proven effective in decreasing the SARS-CoV-2 infection rate. The present study reports on the bacterial filtration efficacy (BFE) of a novel 4-ply functionalized non-woven face mask. We synthesized a polypropylene-based fabric with inner layers of melt-blown fine fibres coated with polylactic acid and immune-boosting herbal phytochemicals. Experimental studies on the synthesized face mask demonstrated a BFE of greater than 99% against Staphylococcus aureus (a bacterium species frequently found in mammalian respiratory tract). A thorough computational analysis using LibDock algorithm demonstrated an effective docking performance of herbal phytochemicals against harmful virus structures. More importantly, the face mask also showed sufficient and stable breathability as per regulatory standards. A breathing resistance of 30 Pa at an aerosol flow rate of 30 l h −1 was reported under standard temperature and pressure conditions, indicating a high potential for real-world applications.

What the COVID-19 pandemic reveals about science, policy and society

The global COVID-19 pandemic of 2020–2021 required politicians to work alongside and depend on scientists more closely than any other event in recent times. It also saw science unfold in real time under intense public scrutiny. As a result, it highlighted as never before the ways in which science interacts with policy-making and with society, showing with sometimes painful clarity that science does not operate in a social or political vacuum. With the advent of vaccines against the coronavirus that has caused the pandemic, science has come to be seen as something of a saviour. But at other times and in other contexts it has also been cast as a villain and an inconvenience, and has run into stark conflict with political leadership. In this article, I consider these issues with particular reference to the situation in the UK—which, as with any nation, illustrated some considerations of more general applicability but also had aspects unique to this country. I argue that there are many lessons to be learnt, and that, as this is surely not the last infectious-disease crisis of such magnitude that the world will face, we must hope they will be heeded.

New ways: the pandemics of science fiction

In unprecedented times, people have turned to fiction both for comfort and for distraction, but also to try and understand and anticipate what might come next. Sales and rental figures for works of fiction about pandemics and other disease outbreaks surged in 2020, but what can pandemic science fiction tell us about disease? This article surveys the long history of science fiction's engagement with disease and demonstrates the ways in which these narratives, whether in literature or film, have always had more to say about other contemporary cultural concerns than the disease themselves. Nonetheless, the ideas demonstrated in these texts can be seen perpetuating through the science fiction genre, and in our current crisis, we have seen striking similarities between the behaviours of key individuals, and the manner in which certain events have played out. Not because science fiction predicts these things, but because it anticipates the social structures which produce them (while at the same time permeating the culture to the extent that they become the touchstones with which the media choose to analyse current events). This paper demonstrates that science fiction can be a valuable tool to communicate widely around a pandemic, while also acting as a creative space in which to anticipate how we may handle similar events in the future.

Miasmas, mental models and preventive public health: some philosophical reflections on science in the COVID-19 pandemic

When the history of the COVID-19 pandemic is written, it is likely to show that the mental models held by scientists sometimes facilitated their thinking, thereby leading to lives saved, and at other times constrained their thinking, thereby leading to lives lost. This paper explores some competing mental models of how infectious diseases spread and shows how these models influenced the scientific process and the kinds of facts that were generated, legitimized and used to support policy. A central theme in the paper is the relative weight given by dominant scientific voices to probabilistic arguments based on experimental measurements versus mechanistic arguments based on theory. Two examples are explored: the cholera epidemic in nineteenth century London—in which the story of John Snow and the Broad Street pump is retold—and the unfolding of the COVID-19 pandemic in 2020 and early 2021—in which the evidence-based medicine movement and its hierarchy of evidence features prominently. In each case, it is shown that prevailing mental models—which were assumed by some to transcend theory but were actually heavily theory-laden—powerfully shaped both science and policy, with fatal consequences for some.