The Kutupalong-Balukhali Expansion Site has 23 congested settlements with nearly 600,000 persons residing there. Despite numerous challenges to the health of the population, including diphtheria and measles outbreaks, the health response and the resilience of the Rohingya refugees has been strong. However, the situation remains precarious and a COVID-19 outbreak in these camps would overload an already fragile health system and poor baseline health status. Using a stochastic disease transmission model, we estimated the number of people infected, hospitalizations, and deaths across three transmission scenarios after a successful introduction of SARS-CoV-2 into the Kutupalong-Balukhali Expansion Site. The introduction of SARS-CoV-2 into the Kutupalong-Balukhali Expansion Site or any other large refugee or internally displaced persons (IDPs) camp or settlement is likely to have serious consequences and overwhelm existing health systems. Even when transmission rates were assumed to be similar to that of influenza (low scenario), the necessary hospitalization capacities far exceeded the available capacities for the refugees in the Expansion Site in most simulations. Recent experience with other infectious disease outbreaks shows that the transmission of SARS-CoV-2 will likely be more intense in contexts such as Kutupalong-Balukhali Expansion Site than in out-of-camp settings because of high population density, inadequate water and soap to maintain hygiene, limited ability to isolate infected individuals, and large household sizes [19].

The younger demographic profile of the Rohingya camp population could reduce the overall rate of severe cases as compared with China or other upper-middle and high-income countries that have older populations. After adjusting for age, we estimate the overall severe disease rate among infections in this population (median=5.1%, [95% CI, 0.6-15.7%]) to be approximately half that estimated for China (median=10.1% [95% CI, 1.8-31.7%]). However, it is likely that co-morbidities such as malnutrition, concomitant diseases, and poor overall health status could cause more severe outcomes among these groups, which was not captured by our model.

Existing inpatient facilities in the camps are already operating close to full bed occupancy, and all scenarios show that they will be overwhelmed. Under current conditions, we expect this to occur within 2 to 4.5 months (55-136 days) of the first introduction of the virus, with cumulative hospitalizations reaching 71 to 25,000 in the first 3 months, depending upon the scenario; these numbers rise dramatically by 12 months. Current hospital bed surge capacity (630) as reported from the site may almost double the number of available beds, but even then, it only delays overwhelming the capacity by 3-10 days on average (S2 Table). Furthermore, while we have focused on the health needs of severe cases, health centers will be flooded with patients with mild to moderate symptoms also seeking care.

While we were unable to find an accurate recent estimate of the human resources currently available in the camps (e.g., number of doctors, nurses, midwives), it is extremely likely that they will be inadequate to face a large influx of patients. Given the limited availability of skilled health workers and hospital beds in Cox’s Bazar, it is unlikely that an additional influx of health care professionals within Bangladesh would be available. A surge of international health care workers could be considered, but this will be difficult given the high demands worldwide during the pandemic and existing travel restrictions.

Furthermore, issues of introduction of the virus from expatriates into Bangladesh would need to be carefully addressed. A more likely strategy will be task shifting among existing health care workers, with physicians treating the most severe cases, nurses the less severe cases, and community health workers addressing mild infections. Such task shifting would require intensive training that needs to begin immediately. An examination of the "re-purposing" of people working in various capacities (e.g., teachers as schools are closed) needs to be undertaken to assess how they can be used to address this epidemic while ensuring integration and complementarity of the response. Prepositioning of PPE and comprehensive training that is constantly reinforced to reduce health care worker exposures is critical to avoid sickness and death among this essential cadre. In particular, the community health workers will have to adapt their method of working to reduce chances of getting infected or infecting others. This may require using texts and calling people in the Rohingya dialect to ensure culturally appropriate communication and education. Furthermore, community health workers can help build trust among the Rohingya that contact tracing and isolation are necessary, and that they can have confidence in these services, given the long history of mistrust among the Rohingya and authorities in Rakhine state, Myanmar [32].

Given the limited number of beds for treating the predicted large number of severe COVID-19 cases in the Expansion Site, isolation through hospitalization, as is being done in other settings, will likely be very difficult. Alternative plans for the isolation of mild symptomatic infections are needed and are currently being discussed with the government of Bangladesh to help control such an outbreak, as was done during the 2017 diphtheria outbreak. Cholera treatment centers and diphtheria outbreak centers that are currently on standby are a low hanging fruit for repurposing. Setting up inclusive and accessible temporary hospitals to triage mild cases in these populations will require significant support and coordination by the government, UN agencies, and NGOs and may be limited by physical availability of land. Therefore, detailed advanced planning of healthcare capacities, triage procedures, and isolation strategies need to be finalized and shared widely as soon as possible.

Novel and previously untried strategies for social distancing and quarantine need to be considered. While culturally difficult and requiring strong socialization, isolating people over 60 years of age and those designated medically vulnerable together, so-called shielding, could be considered. One possibility could be isolating such groups among a group of families and relatives who have confidence in one another [33]. Consistent monitoring of fever and other symptoms combined with appropriate testing will be an integral part of this strategy. Any such shielding must be decided upon wholly by the community after much discussion. It would require sufficient resources to provide comprehensive care (e.g., food and supportive services) for the isolated community members. Since physical distancing will be extremely difficult, the use of facemasks among those most at risk, and possibly the whole population could be considered if there are eventually sufficient supplies. Rapid and creative solutions for improving hand hygiene, such as the installation of a multitude of handwashing stations and distribution of hand sanitizer combined with communication campaigns, will be needed. Access to accurate and consistent health information will be critical, as already rumors and misinformation have spread among Rohingya refugees about COVID-19, partly due to camp-wide restrictions on the internet and telecommunications [4]. In the future, the use of people who have recovered from COVID-19 infections will need to be considered after more data become available as to their ability to become reinfected and transmit to others, as was done with Ebola survivors [34]. The COVID-19 specific programs suggested above will require a strong surveillance system with adequate testing, case finding and isolation, as well as other supplies such as PPE. Such systems and supplies are not yet feasible in the camps, but will be essential to address the epidemic in this setting.

The three scenarios show varying degrees of increased mortality. Mortality due to COVID-19 is dependent upon various factors, particularly access to hospitals with ICUs and ventilators. Currently, there is only one facility with few mechanical ventilators in the camps and one facility with less than 10 ICU beds and no ventilators. Therefore, it is likely that mortality rates due to COVID-19 will be significantly higher here than in settings where nationals or refugees have such access. Reportedly, the ICUs and ventilators are not functioning in the district hospital in Cox’s Bazar, and thus access to health care facilities to treat severe cases of COVID-19 may be equally challenging for nationals. Mortality in Kutupalong-Balukhali Expansion Site is currently comparable to estimates for Chittagong division and nationwide, and are below emergency levels. However, the scenarios show a significant increase in mortality, ranging from 2,040 deaths (3.4/1,000/year) to 2,880 deaths (4.8/1,000/year) at 12 months due to COVID-19 alone; this does not take into account expected deaths that would have occurred during this time as well as increased deaths due to other illnesses that are untreated due to the outbreak.

As in other major epidemics where healthcare capacity and access to it is already limited, major outbreaks like this can easily disrupt an already precarious health system [35]. Diversion of these limited health resources from existing health services, including vaccination, obstetrical care, and emergency care, may cause an increase in mortality due to disease that could normally be treated by the health system; this occurred in the Ebola outbreak in West Africa where more people died from malaria than Ebola, and in Eastern DRC, where more people died from measles than Ebola [36, 37]. Such an increase in non-COVID-19 mortality is particularly concerning with the upcoming monsoon season in Bangladesh.

There are several limitations to this study. We are using a mass-action model, which tends to overestimate the size of outbreaks since populations are generally not closed and well mixed. However, due to population density and often closed nature of refugee camps, transmission in these settings has been shown to act more closely to theory. Additionally, the current evidence on the natural history and key epidemiological properties of COVID-19 reflect the interactions of the SARS-Cov-2 virus with non-displaced populations, and even in those populations many of these parameters remain poorly defined. Population structure and population health can lead to widely different burden of disease with no modifications to the virus. With the particular demographic characteristics and health status of refugee populations, like this one in Cox’s Bazaar, we need to be cautious when developing guidance based on previously estimated properties of SARS-CoV-2/COVID-19. Clinical surveillance, laboratory confirmation, and documentation are key to generating new evidence specific to this population and potentially generalizable to other refugee settings. Thus, we used the existing data that were available from documents and personal communications.

While we are focused here on the possible impact of SARS-CoV-2 on the Kutupalong-Balukhali Expansion Site, most of these findings are applicable to other refugee and IDP camp-like situations. While governments’ preparedness and response plans for COVID-19 may mention forcibly displaced populations, it is the details or lack of, that must be examined. The Inter-Agency Standing Committee recently released interim guidance for scaling up the COVID-19 response in camps and camp-like settings that highlights inclusion, protection, and readiness; and has since developed preliminary multi-sectoral preparedness and response plans [38]. This guidance, which applies the WHO guidance on COVID-19 preparedness and response [39] to populations in humanitarian crises, should be acknowledged in government and humanitarian agency decision-making.

Clear and detailed COVID-19 plans that explicitly state how existing programs will be adapted according to their context need to be developed and shared immediately. For example, different methods of food and fuel distribution will need to be undertaken that address social distancing issues. Potential consequences that isolation and other adaptive programming may cause, such as an increase in intimate partner violence, physical and sexual abuse among unaccompanied minors and other vulnerable groups, and mental health issues must be planned for in a concrete manner. Such adaptive programming will be an iterative process, as these are exceptional circumstances, and we will all have to learn by trying different approaches and then to document the results. A portal should be established by UNHCR and the global health cluster, led by WHO, to document how such adaptive programs for refugees and IDPs are being undertaken in different contexts. There will be a need for increased funding and basic supplies including PPE, as well as large-scale testing capabilities if these plans are to succeed.

The scenarios presented in this study focus on camp-like settings where refugee populations are relatively accessible, and health services are available and generally free. However, the majority of refugees reside outside of camps, often in urban contexts [40]. For these populations, availability, access, cost, and quality of health services vary by host government policies. These refugee populations are also particularly vulnerable to the serious consequences of pandemics as targeted responses among a dispersed group of refugees, and equity in health service delivery is very difficult to achieve.

During exceptional times, it is not unreasonable for governments to take extraordinary measures to protect their citizens; in fact, that is what is expected of governments. Therefore, while difficult for governments to state openly at this point, it is possible that many countries will restrict access to their hospitals to nationals only, particularly when there are large numbers of refugees in the same geographical area. We are already seeing governments closing their border to non-nationals, and in some cases, not allowing people to seek asylum [41]. Such a predicament leaves refugees and other non-nationals, such as undocumented migrants, in an extremely precarious position. During a pandemic, there will be limited support by countries to establish field hospitals with ICU capabilities for refugees in camp-like settings, as they will be occupied with addressing their own national response. Unfortunately, there is no simple recommendation as to how to address this life and death issue. However, we believe it is important to acknowledge the likelihood that host countries’ hospitals will be closed to refugees in most camp-like settings, and consequently, COVID-19 preparedness and response plans should proceed on realistic scenarios.

Finally, refugees face discrimination and are often falsely accused of spreading disease. The widespread rise of populism combined with anti-migrant and anti-refugee sentiments that we are observing globally provides a hostile environment that could be exacerbated by a pandemic. We are concerned that the COVID-19 pandemic, while completely unrelated to being a refugee, could be used as an excuse to take retribution against refugees, as well as other vulnerable groups such as IDPs and undocumented migrants. Such retribution could take many forms, including restricting or stopping asylum seekers, which is currently occurring, the closure of camps, and forced repatriation (refoulement, which is against refugee law), all used in the name of public health. Not only would this be morally wrong, it would jeopardize the effectiveness of containment and mitigation measures, as pandemics require planning and responses that do not discriminate by nationality and protect the health of the global population.

Our findings suggest a COVID-19 epidemic among the Rohingya refugees in the Kutupalong-Balukhali Expansion Site will be extremely difficult to mitigate. Many of the current interventions such as social distancing, contact tracing and isolation, good hygiene, and sophisticated treatment in ICUs for critical cases will be challenging to implement. How SARS-CoV-2 will transmit and how COVID-19 will manifest in such a population with a poor baseline heath status and acute malnutrition is simply unknown at present. Beyond preparing now for COVID-19 through specific and sensitive interventions for this population to reduce morbidity and mortality, there is a need to rigorously document what does occur when the epidemic affects such a refugee population so we can learn how to better prepare and respond in similar settings. This will require strong surveillance systems to be established now. It will require working closely with the community to better understand how social distancing can work for them in their situation. And it will require the continued commitment of the brave health care workers and the refugees themselves to respond to this pandemic.