Dr Osama B Hassan tells HEQ about the impact of COVID-19 on efforts to combat ongoing threat of cholera.
While the focus of healthcare research and reporting has understandably been primarily on the COVID-19 pandemic in the last year, other diseases and conditions have presented a quietly growing threat; particularly in low-income and developing nations.
Dr Osama B Hassan, of the Division of Epidemiology and Public Health in the University of Nottingham’s School of Medicine, co-authored an article in The Lancet’s EClinical Medicine journal earlier this year titled ‘Cholera during COVID-19: the forgotten threat for forcibly displaced populations’; he tells HEQ about the impact of COVID-19 on efforts to combat ongoing threat of cholera.
What is cholera?
Cholera is an acute, secretory diarrhoeal infection caused by the bacterium Vibrio cholerae1. It is a waterborne disease transmitted by the faecal-oral route by consumption of contaminated water or food containing the organism. Patients infected with Vibrio cholerae can be asymptomatic or develop acute, painless rice-water diarrhoea (20%)2. Approximately 10% to 20% of patients infected with cholera develop severe diarrhoea, vomiting, and dehydration3. Cholera is very preventable, but untreated and severe infections can lead to death in 50% of cases. Proper and timely management reduces the risk of cholera death to less than 1%3.
How prevalent is cholera and which regions are most severely affected?
Several cholera pandemics have happened over time. The current seventh pandemic is considered the longest pandemic, as it started in 1961; and has affected all the World Health Organization (WHO) regions and caused millions of deaths worldwide4. Annually, cholera affects approximately 2.9 million people leading to 95,000 deaths worldwide, mostly in low- and middle-income countries (LMICs)5. The global annual incidence rate of cholera is 2.0 per 1000 people5. Cholera is endemic in approximately 47 countries, mainly in Asia and Africa, with 1.4 billion people living at risk of the infection5. In Africa alone, circa 40 million people live in cholera-endemic areas with a risk of frequent outbreaks5; whereas cholera is eradicated in the developed nations due to establishing proper water and sanitation infrastructure1. The social and economic burden of cholera endemics and epidemics is highly significant as it results to travel restriction, a decline in rates of the tourism industry, food trade, and development progress of these countries6. This sometimes leads to underreporting of cholera cases in some regions6.
What are the key factors behind cholera outbreaks in areas such as Ethiopia, Sudan and Yemen?
Cholera is a disease of poverty that affects the poorest and most vulnerable people. The risk factors of cholera transmission are mostly attributed to poor living conditions and lack of water, sanitation, and hygiene (WASH) services7. This includes limited access to clean water supply with good quantities that increase exposure to contaminated water sources and unsafe storage and transportation of water8. The other factor is inadequate sanitation facilities and sewage systems, such as lack of sufficient and appropriate latrines, lead to breaking the barrier between excreta and human contacts which causes food and water contamination7. Furthermore, pollution of water and food can be caused by some unhygienic practices such as scarcity of soap and water, lack of handwashing practices, and communal sharing of water containers7.
Additionally, cholera usually thrives in humanitarian crisis settings following natural disasters or complex emergencies which result in massive displacement and overcrowding; disruption of health and public services; famine; and lack of provision of WASH services7. Over two billion people drink contaminated water, and 2.4 billion live without basic sanitation services, exposing them to cholera and other waterborne diseases9. These factors lead to areas endemic with cholera with seasonal or sporadic outbreaks. For instance, cholera has been endemic in sub-Saharan Africa for decades with recent outbreaks such as in Nigeria, Somalia, and Ethiopia10. In Yemen, since the outbreak of civil war in 2016, cholera has led to over 2.3 million cases and 4000 deaths11.
Has the COVID-19 pandemic had an impact on international measures to prevent and treat cholera, including vaccination programmes?
Extreme concerns have been raised regarding the spike of cholera and other infectious diseases during the COVID-19 pandemic. An increase in cholera cases in the endemic areas has been reported in comparison to previous years, as the pandemic has caused disruptions in diagnosis and treatment services; delivery of vaccination programmes including cholera vaccines; and provision of proper WASH services12. Furthermore, the COVID-19 pandemic has resulted in a lack of access to humanitarian aid and has also resulted in an increase in the pressure on health systems in cholera- endemic countries, which may be unable to handle two or more outbreaks at the same time due to lack of capacity in personnel and supplies12. WHO and UNICEF have experienced additional challenges in dealing with the recent cholera outbreaks in Somalia, Uganda, and Yemen amidst the COVID-19 pandemic as it has added an extra burden on the existing, limited resources13–15.
Provision of safe WASH services and commodities is pivotal in preventing infection and protecting human health during infectious disease outbreaks, including cholera and the current COVID-19 pandemic. It has been proved that washing hands with water and soap kills 70% of pathogens, including the COVID-19 virus, and decreases diarrhoea case rates by 40%15. However, the emergency responses to COVID-19, including the applied protection measures such as lockdowns and curfews, as well as the socioeconomic impacts of the virus, have collectively led to a decline in the provision of WASH services, particularly in LMICs and regions experiencing humanitarian crises. This is attributed to lack of funding, disruption of chain equipment supply, shortfall of staff, increased water demand, and inflated prices of WASH services and commodities16. In Yemen, 60% to 70% of the population suffer from a lack of access to sufficient and safe water and soap15. Across the country, approximately 20.4 million people need humanitarian aid to enable them to access proper and adequate WASH services15. Around 11.2 million are in urgent need and their lives are highly threatened by severe infectious diseases15.
According to the World Health Organization, UNICEF, and GAVI, the Vaccine Alliance, COVID 19 has led to considerable disruption of immunisation programmes around the world, mainly in LMICs, putting millions of lives at risk of vaccine-preventable diseases17,18. In May 2020, a total of 99 countries reported the suspension of immunisation campaigns including oral cholera vaccines (OCVs)17. This has been due to increased production cost and difficulties in shipments and supply in the wake of protective measures which have been taken to contain the spread of COVID-19 infection18. As a result of the disrupted supply of vaccines, countries across West and Central Africa, East and Southern Africa, East Asia, and South Asia have reported significant drops in vaccine stocks and five nations have stopped oral cholera vaccination programmes entirely17,18. However, the Global Task Force on Cholera Control (GTFCC) reported successful emergency OCV campaigns during COVID-19 in the Democratic Republic of Congo, Uganda, and South Sudan in response to heavy torrential rains and floods19.
Has the pandemic led to heightened awareness of essential infection control measures? How can the lessons learned from the pandemic be deployed to slow the spread of cholera?
The COVID-19 pandemic has clearly highlighted the importance of personal hygiene practices to prevent and control of infectious diseases, let alone waterborne diseases like cholera. The availability of proper and sustainable WASH utilities and products is not only reducing the transmission of COVID-19 but also prevents the secondary impacts of the COVID-19 pandemic, including the potential outbreaks of cholera and other waterborne infections, particularly in most vulnerable communities and endemic areas. This includes access to safe drinking water; access to basic sanitation facilities (sufficient latrines connected to proper swage systems); access to hand-washing services including soap and water and alcohol-based hand rubs for each household; and community engagement and awareness to improve personal hygiene practices20.
The World Bank has recommended the provision of these services in healthcare facilities, schools, workplaces, markets, transport stations, and other areas of people gathering20. The provision of safe and well-managed WASH services is emphasised by the United Nations’ Sustainable Development Goals (SDGs) in both Goal 3 (‘ensuring healthy lives and wellbeing for all’) and Goal 6 (‘access to water and sanitation for all’), to improve the health and wellbeing of the poorest and most vulnerable populations (those most often affected by cholera)9. However, according to GTFCC, over 80% of cholera hotspot countries reported insufficient funding to meet their WASH targets as global water and sanitation aid has dropped over the last few years9. Taking into account the impact of the COVID-19 pandemic, this could delay the implementation and maintenance of WASH services in cholera-endemic regions and ultimately lead to increase in the risk of further cholera outbreaks.
The focus on the importance of vaccines in the protection against infectious diseases has been enormous during the current pandemic. In 2013, WHO created a global stockpile of two OCVs, Euvichol and Shanchol21. These vaccines are delivered in two doses and provide protection for at least two to three years with 76% effectiveness. OCVs have been a game-changer in fighting cholera outbreaks, as they work immediately to prevent cholera outbreaks and give time to implement WASH services in emergency settings9. More than 15 countries have conducted OCV campaigns in cholera-endemic regions (preventive); cholera epidemics (reactive); or humanitarian emergencies (pre-emptive)9. This cumulative experience in rolling out OCVs can be exploited to overcome the barriers for COVID-19 vaccine delivery in cholera-endemic countries. These vaccines can be delivered concurrently with COVID-19 vaccines as they share similar features; they are given in two doses in emergency settings with limited supply, so the rollout strategy prioritises people who are most vulnerable. Promoting the OCV supply through increasing and maintaining the global stockpile or by facilitating the manufacture of OCV by nations with cholera hotspots is very crucial to reducing or even ending the risk of cholera.
The other clear message from the current pandemic is the role of prediction, preparedness, and early response. The first step in controlling and significantly reducing the death toll of cholera, COVID-19 or other outbreaks is to strengthen preparedness capacities, improve early detection and laboratory confirmation, and timely and proper response to outbreaks in order to reduce their impacts9. This includes implementing and strengthening of proper early warning surveillance systems for all possible infection outbreaks, including suspected cholera cases. This should be coupled with improving laboratory capacities to confirm the pathogen, detect strains and test for antibiotic susceptibility.
A rapid and effective response to cholera requires strengthening of healthcare systems through pre-positioning of essential supplies (oral rehydration solution, IV fluids, cholera kits, high test hypochlorite); improving healthcare infrastructure; establishing dedicated healthcare facilities (Cholera Treatment Centres and Cholera Treatment Units); and training of healthcare workers9. Additionally, community-based interventions to promote hygiene practices and community engagement and awareness; implementation of reactive large-scale mass vaccination campaigns with OCV; and building and strengthening the already existed WASH services should be initiated in the meantime. The experience of the current pandemic could be exploited to improve the infection prevention and control systems to fight this pandemic and other ongoing threats of infectious diseases, including cholera22.
Is there a need for further action from international and humanitarian bodies, such as the European Commission or the WHO, to assist countries struggling with cholera?
The spread of cholera is highly related to areas with severe deprivation and social inequality around the world. Therefore, supporting and improving the quality of life of communities that are vulnerable to cholera and ensuring that no one is lifted behind is highly recommended. This can be attained through going forward with achieving the SDGs adopted by the United Nations, in terms of reducing poverty and hunger; promoting education and learning; and ensuring availability of sustainable clean water and sanitation for everyone23. Reducing inequality and poverty, and empowering communities, are key in supporting GTFCC’s strategy to reduce cholera deaths by 90% in 2030 in order to eradicate cholera completely. This is also essential to be well-prepared to face and minimise the impact of any potential pandemic in the future.
1 Rabaan, AA. Cholera: an overview with reference to the Yemen epidemic. Front. Med. 13, 213–228 (2019).
2 WHO. Cholera. www.who.int/en/news-room/fact-sheets/detail/cholera (2019).
3 OXFAM. Cholera Outbreak Guidelines, Preparedness, Prevention and Control. (2012).
4 Reveiz, L et al. Chemoprophylaxis in contacts of patients with cholera: Systematic review and meta-analysis. PLoS One 6, e27060 (2011).
5 Ali, M et al. The global burden of cholera. Bull World Heal. Organ 90, 209–218 (2012).
6 WHO. WHO | Global epidemics and impact of cholera. WHO (2010).
7 Wolfe, M, Kaur, M, Yates, T, Woodin, M, Lantagne, D. A systematic review and meta-analysis of the association between water, sanitation, and hygiene exposures and cholera in case-control studies. Am. J. Trop. Med. Hyg. 99, 534–545 (2018).
8 Connolly, MA et al. Communicable diseases in complex emergencies: Impact and challenges. Lancet vol. 364 1974–1983 (2004).
9 GTFCC. Ending cholera: a global roadmap to 2030. (2017).
10 Mengel, MA, Delrieu, I, Heyerdahl, L, Gessner, BD. Cholera outbreaks in Africa. Current Topics in Microbiology and Immunology vol. 379 117–144 (Springer Verlag, 2014).
11 WHO. WHO EMRO Weekly Epidemiological Monitor: Volume 14, Issue no 7; 14 February 2021 – Yemen | ReliefWeb. Situation Report: https://reliefweb.int/report/yemen/who-emro-weekly-epidemiological-monitor-volume-14-issue-no-7-14-february-2021 (2021).
12 IRC. Deadly malaria and cholera outbreaks grow amongst refugees as COVID pandemic strains health systems, warns IRC – World | ReliefWeb. News and Press Release: https://reliefweb.int/report/
13 WHO EMRO. WHO EMRO | Outbreak update – Cholera in Somalia, 24 January 2021 | Cholera | Epidemic and pandemic diseases: www.emro.who.int/pandemic-epidemic-diseases/cholera/outbreak-update-cholera-in-somalia-24-january-2021.html (2021).
14 Alex Taremwa. Fighting a cholera outbreak in the middle of a COVID-19 pandemic | UNICEF Uganda: www.unicef.org/uganda/stories/fighting-cholera-outbreak-middle-covid-19-pandemic (2020).
15 Advocacy brief: A Water Crisis in the time of COVID-19 Impact of funding shortages on Public Health in Yemen Background-COVID-19 on top of a humanitarian crisis. (2020).
16 Puneet Srivastava, MM and RF. Water and sanitation service providers and the challenges of COVID-19 | WASH Matters: https://washmatters.wateraid.org/blog/water-and-sanitation-service-providers-and-the-challenges-of-covid-19 (2020).
17 Gavi. COVID-19: massive impact on lower-income countries threatens more disease outbreaks | Gavi, the Vaccine Alliance: www.gavi.org/news/media-room/covid-19-massive-impact-lower-income-countries-threatens-more-disease-outbreaks (2020).
18 UNICEF. Impact of COVID-19 on vaccine supplies | UNICEF Supply Division: www.unicef.org/supply/stories/impact-covid-19-vaccine-supplies (2020).
19 OCHA. ETHIOPIA-TIGRAY REGION HUMANITARIAN UPDATE Situation Report: https://reports.unocha.org/en/country/ethiopia/ (2020).
20 WASH (Water, Sanitation & Hygiene) and COVID-19. www.worldbank.org/en/topic/water/brief/wash-water-sanitation-hygiene-and-covid-19.
21 WHO. WHO | Oral cholera vaccines: www.who.int/cholera/vaccines/en/ (2018).
22 Hassan, OB, Nellums, LB. Cholera during COVID-19: The forgotten threat for forcibly displaced populations. EClinicalMedicine 32, 100753 (2021).
23 UN. THE 17 GOALS | Sustainable Development: https://sdgs.un.org/goals.
Dr Osama B Hassan
Division of Epidemiology and Public Health
School of Medicine
University of Nottingham