COVID-19: urgent actions, critical re ﬂ ections and future relevance of ‘ WaSH ’ : lessons for the current and future pandemics

The COVID-19 pandemic placed hygiene at the centre of disease prevention. Yet, access to the levels of water supply that support good hand hygiene and institutional cleaning, our understanding of hygiene behaviours, and access to soap are de ﬁ cient in low-, middle- and high-income countries. This paper reviews the role of water, sanitation and hygiene (WaSH) in disease emergence, previous outbreaks, combatting COVID-19 and in preparing for future pandemics. We consider settings where these factors are particularly important and identify key preventive contributions to disease control and gaps in the evidence base. Urgent substantial action is required to remedy de ﬁ ciencies in WaSH, particularly the provision of reliable, continuous piped water on-premises for all households and settings. Hygiene promotion programmes, underpinned by behavioural science, must be adapted to high-risk populations (such as the elderly and marginalised) and settings (such as healthcare facilities, transport hubs and workplaces). WaSH must be better integrated into preparation plans and with other sectors in prevention efforts. More ﬁ nance and better use of ﬁ nancing instruments would extend and improve WaSH services. The lessons outlined justify no-regrets investment by government in response to and recovery from the current pandemic; to improve day-to-day lives and as preparedness for future pandemics. (cid:129) The paper analyses the structural de ﬁ ciencies in the WaSH ‘ sector ’ that limits its impact on COVID-19. (cid:129) The paper identi ﬁ es key evidence gaps, including on behaviour change, that are priorities for maximising the role of WaSH in addressing pandemics of disease.


INTRODUCTION
The world in 2020 has been gripped by a pandemic of a novel coronavirus, severe acute respiratory syndrome coronavirus 2, cause of  Starting in China in late 2019, by the end of July 2020, this had spread to virtually every country in the world, with global cases escalating past 15 million and over 600,000 deaths at the time of writing.
Combatting a virus to which the population at large has no immunity, which is highly contagious and for which no vaccine exists, has forced countries to recognise the importance of foundational measures of disease control.
'Physical distancing' and 'physical isolation', accompanied by handwashing and infection prevention and control, have been the main responses. Box 1 clarifies these terms.
All are challenging in low-, middle-and high-income countries, albeit for different reasons.
In this paper, we analyse the role of WaSH in reducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission and supporting responses to . We explore how the importance of adequate WaSH services is reinforced by evidence from other outbreaks and pandemics of contagious and infectious disease. 2 We address the roles, strengths and weaknesses of WaSH by analysing the three necessities for sustained handwashing (availability of sufficient flowing water, availability of soap and hand sanitisers where used and behaviours practiced by individuals) and then consider WaSH in settings of specific concern.
We identify actions needed to ensure WaSH supports prevention and response to pandemics and identify important knowledge gaps and priorities for research.

COVID-19
Most people with COVID-19 experience mild to moderate respiratory illness and recover without requiring special treatment.
Some people with COVID-19 have no symptoms and asymptomatic infections likely contribute to the spread of the disease.
The infection may also cause severe illness including respiratory failure and multiorgan and systemic manifestations (sepsis, septic shock and multiple organ dysfunctions) (Cascella et al. ). Older people and those with underlying medical problems are more likely to develop serious illness. 1 There is confusion and misuse of terminology related to the current disease pandemic. The term 'COVID-19' refers to the disease that is caused by the virus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 transmission appears to be largely through inhalation and through respiratory droplets 3 contacting mucosae (mouth and nose) or conjunctiva (eyes). Contact occurs directly through person-person (e.g. droplet-hand-hand-face) and indirectly (e.g. droplets-surfaces-hands-face). Consequently, the principal WaSH responses to COVID-19 relate to hand hygiene. While the relative contributions of inhalation and contact to transmission are unclear, the necessity of hand hygiene to disease control is unquestionable.
In some patients, the shedding of viral RNA via the digestive system appears to last longer than via the respiratory tract (Wu et al. a; Xu et al. ). Infectious viruses, as distinct from RNA markers for SARS-CoV-2, have been isolated from very few stool samples (Wang et al. ), even during clinical and asymptomatic infection. Faeces are, therefore, unlikely to contribute substantially to infection.

THE IMPORTANCE OF HANDWASHING
A person infected with SARS-CoV-2, whether symptomatic or asymptomatic, is likely to have contaminated hands and may transmit the pathogen to others, directly or via surfaces and objects (fomites). Hands offer a conducive environment for virus survival as they contain creases that protect against exposure to viricidal ultra-violet (UV) light, specifically UV-C (IES ). to have been exposed to the virus. While these terms are used widely, there are some variations in application.
Isolation is sometimes conflated with quarantine and although the terms self-isolation and self-quarantine usually refer to voluntary actions, in some jurisdictions compliance with these actions is enforced. Physical or social distancing refers to measures used to reduce contact between people, such as staying at home and maintaining physical gaps between noncohabiting individuals. The recommendations for specific separation distances vary across countries and range from 1 to 2 m (3-6 feet). Physical distancing is a more accurate description of this measure since a continuation of social contact is encouraged (e.g. electronically).
3 Both respiratory droplets and respiratory aerosols are liquid (mucus) particles and are potentially infectious through inhalation if they contain virus. The terms 'aerosol' and 'droplet' are often confused and some definitions are ambiguous (Vuorinen et al. ). 'Aerosols' is sometimes used to refer to a suspension of liquid droplets or droplets of smaller sizes after drying of particles in the air, but the term strictly refers to small droplets that remain suspended in the air. Droplets larger than aerosols are heavier than air and are deposited under gravity. The difference is important for inhalation exposure and to deposition of viruscontaining particles on surfaces.
transmission. In both cases, the authors note that insufficiently frequent handwashing may explain their findings.

Hygiene behaviours and facilities
Effective handwashing requires access to facilities (water, containers, soap) that enable hygiene behaviours. Wolf et al. () report that 95% of the population in high-income countries has access to a 'designated handwashing facility', but only 70% in low-income countries; and in sub-Saharan Africa, the population in households with access to handwashing facilities with soap and water is 26% (UNICEF & WHO ).
UNICEF & WHO () report that around 60% of the world's population has at least a basic handwashing facility in the household, defined as a location where both soap and water are available that are either fixed (i.e. a sink) or mobile (jugs or basins). Mobile handwashing facilities are unlikely to be adequate to support the levels of hygiene sought in response to COVID-19. A systematic review by Brauer et al. () found that, in 2019, 2.4 billion people worldwide lack access to handwashing with available soap and water. They note substantial regional variation, with over 50% of the population in the sub-Saharan Africa and Oceania regions lacking access, and that access was particularly low in rural areas and urban slums in low-income countries.
Construction of handwashing stations (e.g. 'tippy-taps', which do not require running water) encourage handwashing with soap (Contzen et al. ; Coultas et al. ). An integrative review on determinants of hand hygiene found good and consistent evidence that handwashing infrastructure in the household was a determinant of handwashing (White et al. ). Wolf et al. () show that people with access to a handwashing facility with soap and water were 2.6 times as likely to wash hands with soap before food contact compared to those people without access to a handwashing facility.

Sufficient flowing, reliable water
Adequate hand hygiene requires sufficient water from reliable and easily accessible sources, preferably piped to their premises. UNICEF & WHO () estimate that 90% of the global population uses at least an 'improved water supply' and 64% of this population has access to piped water, some of whom use shared taps and many who experience intermittent supply (Kumpel & Nelson ). Majuru et al. () found that unreliable water supplies have been associated with poorer domestic hygiene, which may increase the spread of COVID-19 via fomites. Three-quarters of the global population has some form of water supply on-premises (UNICEF & WHO ), which includes households with their own wells. While such water sources can provide a reliable and abundant supply of water, they will not provide running water for washing hands.
UNICEF & WHO () report that one-quarter of the global population uses water collected from off-premises water sources that are shared between households. Reliance on such sources creates two challenges to the pandemic response: sufficiency of water for handwashing and interhousehold contact associated with water collection, the latter disproportionately exposing women and girls. The amount of water typically collected by households from such sources is around 20 litres per person per day (Howard & Bar-tram ), which Howard et al. (in press) note that is unlikely to be sufficient to support the greater frequency and duration of handwashing required in pandemics and outbreaks. Shared water sources are places of inter-household contact. Their use increases the risk of transmission because handles and taps used by numerous people facilitate contact transmission.
There is no evidence that the SARS-CoV-2 virus can be transmitted via contact with water. Thus, frequent handwashing with lower quality water is preferable to infrequent handwashing in high-quality water when a pandemic response is paramount.

WASH IN SETTINGS OF SPECIFIC CONCERN FOR COVID-19
Most countries have promoted physical isolation at home for people who suspect they may have the disease. While effective There are a number of extra-household settings of concern (Table 1). Healthcare facilities, transportation systems and forcibly displaced people are of particular concern either because of the potential to act as hubs of infection or the vulnerability of their populations.

PREPARING FOR 'FUTURE WAVES' OF OUTBREAKS
The preceding review concerns challenges to, and immediate needs for, WaSH during the first active phase of the pandemic. This paper was prepared as cases escalated in some countries, re-escalated in others and some countries lifted initial 'lockdown' restrictions. Local increases in the reproductive rate (R 0 ) 4 and fears that infection, and potentially vaccination, may not induce lasting immunity increased concern for 'future waves' of infection. Under all these circumstances, as restrictions are eased, frequent hand hygiene will be critical to keeping the reproductive rate (R 0 ) below 1, as will restrictions on inter-personal contact, especially for cases and their contacts. easy-access hygiene/washing facilities that minimise interindividual and inter-household contact.

WaSH, COVID-19 and human rights obligations
COVID-19 disproportionately affects the lives and livelihoods of certain individuals and groups and the pandemic therefore has the potential to exacerbate long-standing inequalities and unequal determinants of health (Laurencin Table 1 | Settings of concern for COVID-19

Setting Issues
Healthcare facilities Separating COVID-19 patients and surges in the number of severe cases, overburden water systems and facility hygiene. Deficient healthcare facilities can become epicentres of infection, as with cholera (Mhalu et al. ) and Ebola (Faye et al. ). In many low-and middle-income countries, facilities are chronically under-staffed (WHO ) and resources for cleaning and disinfection are insufficient. Only 2% of facilities, in low-and middle-income countries with data, had adequate water, sanitation, hygiene, waste management services and standard precaution items (i.e. PPE) (Cronk & Bartram ). WHO & UNICEF () note that 74% of healthcare facilities had at least an improved water source on premises (55% for 'least developed' countries and 51% in sub-Saharan Africa); and 16% had no hygiene service (no water and no sanitation and no handwashing facilities). Conventional sanitation facilities require hand-surface contact (door handles, taps, seats, etc.).

Transport
National responses to COVID-19 restrict movement because disease spreads through transportation corridors, as with cholera ( Persons from different households are crowded together in transport and at transport hubs. Transport hubs (bus and train stations, shared taxi boarding points, ports and airports) are high-risk locations. They require more frequent hygiene behaviours and enhanced facility cleaning and disinfection during pandemics. Pay-to-use facilities discourage desired behaviours and impede frequent hand hygiene. Public or shared transport (buses, trains, shared taxis, ferries, aeroplanes) is often over-crowded and hand sanitiser on entry and exit and frequent disinfection are needed. Regulating hygiene, regular cleaning and eliminating over-crowding demand assertive action by governments. In many countries, migrant labourers have left towns and cities to return their home villages and are exposed to high-risk environments during travel. Facilities in home villages may be insufficient to cope with the increased demand.
Forcibly displaced populationsrefugees and internally displaced people Numbered over 70 million people in 2018 (UNHCR ), more than 60% live in urban host communities rather than camps. Most refugees flee to nations that have not met the WaSH needs of their citizens. Governments anticipate displaced population return to their country of origin, but the average refugee spends 17 years displaced ( . Migrant hostels represent a specific setting of concern as they are often over-crowded with limited WaSH facilities; migrants may be indebted as part of arrangements for their employment meaning they must continue to work; and the rights of migrants may be limited. Penal institutions and homeless shelters tend to have higher proportions of people with other health problems that may increase susceptibility. A group of UN independent human rights experts, in March 2020, called on utilities to provide water free of cost to certain population groups, saying: 'We call on governments to immediately prohibit water cuts to those who cannot pay water bills. It is also essential that they provide water free of cost for the duration of the crisis to people in poverty and those affected by the upcoming economic hardship. Public and private service providers must be enforced to comply with these fundamental measures' (OHCHR ).
Ensuring that all people have access to sufficient water must be accompanied by ensuring the viability and sustainability of water service providers. The indirect effects of the COVID-19 pandemic on staff and supply chains may affect WaSH services and consumables. For example, utilities may face immediately reduced and in the longer-term slower customer growth, deferrals of planned water rate increases and deferred maintenance. Financial losses may reduce capital spending. These short-and long-term costs will be substantial, for instance, in the USA, financial losses to utilities are estimated to be US$13.9 billion and the economic impacts US $32.7 billion (Raftelis ). Globally, the water supply services that are most likely to fail are smaller systems with single operators.
Improved governance, in particular strong and supportive regulation, is essential to prevent failures and minimise drain on public finance by ensuring utilities have finance available and make sensible investments. Supplyside direct subsidies may prove difficult to unwind. While the short-term response may be a time-limited supply of water, the medium-term response is likely to involve demand-side subsidies that allow households to take responsibility and that can be better targeted and monitored.

LESSONS FOR WASH FROM EMERGING DISEASES AND MANAGING WASH-RELATED OUTBREAKS
Pandemics in which WaSH has a role in prevention and control, and the emergence of new diseases linked to  Understanding emergence mechanisms is critical to prevent pandemics. The risk of emergence of a pathogen seems   • The importance of understanding places and population groups of concern (e.  In some countries, responses to COVID have included closing public toilets. They represent the only practical means for handwashing where hand sanitiser is not available or used, and for those travelling (e.g. for work or to purchase necessities) and are the primary resort of the homeless for sanitation and hygiene. Whether such closures are justified based on the balance between facilitating hygiene and surface contact risk is poorly understood, as are the means to minimise the latter.
A cross-cutting concern is the need for the sometimes insular 'WaSH sector' to engage more extensively and effectively with other 'sectors' and professional communities.
The constrained scope of WaSH means engagement in the prevention of disease emergence and in emergency preparedness is slight. This is also manifest in prevention through adequate WaSH in healthcare facilities and is applicable to transport, workplaces, schools and care for the elderly. Understanding the specific roles of the health sector in relation to WaSH, as described by Rehfuess et al.

WASH IN PREPAREDNESS AND RESPONSE TO FUTURE PANDEMICS
The prevention and control of pandemics is a common good it merits support because of the significance to the population at large as well as individual benefits. This is more than a conceptual issuehistory shows that thenunprecedented investment in public water and sanitation systems in eighteenth-century Europe were elicited by selfpreservation by the wealthy against diseases that showed no respect for class or wealth (Hamlin ). History also shows that, in the face of existential threats, there is a strong appetite for public expenditure and that speedy transformational investments can be made.
The introduction of this pandemic prevention and response perspective to WaSH modifies and expands the SDG commitments. Firstly, it highlights and confirms the targets adopted for household level access to water to support the called-for hygiene behaviours. However, here we call for the target and its monitoring to be upgraded to piped water on premises and for discontinuous piped supply to be aggressively tackled. Secondly, common-good arguments have been made for sanitation (Langford et

Financing and instruments
A common thread from repeated outbreaks concerns finance, and in particular, the role of public financing from tax revenues. The common-good justification for public finance in pandemics is that people who cannot purchase sufficient soap and water pose a public health risk to society.
There is a major water and sanitation infrastructure deficit in many countries, particularly because of the evident need for water piped on-premises. Investments in water supply infrastructure by households, governments and development partners will be a critical part of the solution.  The pandemic highlights that adequate hygiene and access to safe and reliable water and sanitation are essential to preparedness, prevention and response; as well as protecting human life at other times. There is a widespread implicit assumption by policy-makers and health planners that they can call on a 'WaSH sector' that is able to respond to information needs and to provide basic services to support pandemic control. This is manifestly incorrect in many countries.
In the current pandemic, we have seen water supply treated as an essential service; however, there is little evidence for policy responses to increase access to, or reduce intermittence in, supply that would support households in accessing sufficient water and sustaining the handwashing required. Reliance on communal water sources lessens the ability to adopt physical distancing and prevents households reliant on such sources from self-isolating. These are policy failures within the WaSH sector and in wider public policy.
They arise from structural deficiencies that result in poor planning, weak governance, mis-focused prioritisation and under-investment. Financing instruments that could help reduce inequalities in service provision should be urgently considered.
Ensuring universal access to safe and reliable water, hygiene and sanitation services for all populations and in all settings is justified: from both a common-good perspective, for pandemic preparedness, and as 'no regrets' longevity use of resources mobilised during pandemic response. Both success and failure in these endeavours will disproportionately affect (benefit or undermine the precarious conditions of) the poor and the vulnerable. Action solely at the time of need cannot provide a sufficient response, long-term investment and engagement with key actors and stakeholders are essential to both preparedness and response.
COVID-19 exemplifies the critical need for safe healthcare facilities. Some responses will involve temporary treatment centres, with associated full WaSH facilities. One consequence is that investments to improve COVID-19 reminds us that hygiene, safe water and sanitation are essential to protect human life. Short-term action should rapidly ensure that everyone can access sufficient water and soap to practice good hygiene and hygiene facilities are available in all public places. In the medium term, a priority is reliable sustained water supplies and sanitation systems that meet enhanced SDG targets, as we propose here. In the long term, WaSH systems must be sustainable and resilient to future threats, including those associated with climate change, and contribute to preparedness for, prevention of and response to pandemic disease.

DATA AVAILABILITY STATEMENT
All relevant data are included in the paper or its Supplementary Information.