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COVID-19 control in low-income settings and displaced populations: what can realistically be done?

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Background

While modelling predictions suggest that uncontrolled or even partially mitigated COVID-19 epidemics in high-income countries could lead to substantial excess mortality, the virus’ impact on people living in low-income settings or affected by humanitarian crises could potentially be even more severe. Three mechanisms could determine this: (i) higher transmissibility due to larger household sizes, intense social mixing between the young and elderly, overcrowding in urban slums and displaced people’s camps, inadequate water and sanitation, and specific cultural and faith practices such as mass prayer gatherings, large weddings and funerals during which super-spreading events might propagate transmission disproportionately; (ii) higher infection-to-case ratios and progression to severe disease due to the virus’ interaction with highly prevalent co-morbidities, including non-communicable diseases (NCDs; prevalence of hypertension and diabetes is often higher in low- than high-income settings, with a far lower treatment coverage), undernutrition, tuberculosis and HIV; and (iii) higher case-fatality due to a dire lack of intensive care capacity, especially outside large cities. Moreover, extreme pressure on curative health services could result in indirect impacts resulting from disrupted care for health problems other than COVID-19. While these risk factors could be counterbalanced by younger age distributions and hot temperatures, on balance we believe that, given current evidence and plausible reasoning, drastic action is required immediately to protect the world’s most fragile populations from this unfolding threat.

Containment may buy some time – at best

Over the last week, low-income and crisis-affected countries are following a global pattern of attempting to interrupt further importation of COVID-19 from abroad through border closures, while also implementing various social distancing and quarantine measures. Examples from China, South Korea and Singapore suggest that this approach may enable containment at least for some time; it is, however, very resource-intensive, entailing widespread testing and meticulous contact tracing. It is doubtful that these measures are replicable in low-income and crisis settings, where inadequate surveillance and less-than-sufficient testing may initially obfuscate the true extent of locally driven transmission. Moreover, extreme population-wide social distancing and travel restrictions, if sustained over a long period, could be very harmful for fragile, export-dependent economies and stretch livelihoods beyond people’s coping ability, in turn dis-incentivising adherence to control measures. In short, a draconian containment strategy may be useful for a limited time to allow countries to better prepare, but risks failing beyond a horizon of weeks.

What can realistically be done?

Of the three mechanisms we describe above, two (higher infection severity and case-fatality) appear less tractable for the time being. Some interventions could help and should be pursued quickly (e.g. maintaining NCD, TB and HIV case detection and treatment coverage; intermittent presumptive treatment to reduce other co-morbidities; freeing up health care capacity by postponing non-essential services). However, there appears to be little realistic prospect of scaling up intensive care to the levels required; isolation of cases in dedicated, but not high-intensity wards might offer neither clinical benefit nor meaningful transmission reductions, as most transmission would still be attributable to low-risk infections and the proportion of the infectiousness period spent pre-admission, e.g. among household members. Moreover, without sufficient training and infection control supplies, such facilities would pose a major threat to the health of clinicians, already a very scarce resource in most low-income and crisis settings.

By contrast, the mechanism of higher transmissibility appears more amenable to economically and socially feasible interventions, even in the most resource-constrained settings. Here too, however, a range of possible strategies may be considered. Even as containment measures are pursued, governments in resource constrained settings are already promoting population-wide social distancing measures. Realistically, to achieve sufficient impact these would require most non-essential workers to work from home or not at all, a strategy ill-suited to the economies and remote-working capability of low-income settings. Moreover, this must be sustained over a long period, until a vaccine, treatment or both are available at scale. We thus suggest that, where dispersive strategies targeting the general population are difficult to implement and/or cannot be sustained, leading to ongoing transmission among low-risk populations, it will be more impactful and efficient to focus resources on protecting those most vulnerable.