What do a failed South American state, a war-torn Middle Eastern country and a South Asian country with a large refugee population have in common? Not much at first sight, but all three have recently been experiencing large diphtheria outbreaks, killing dozens and affecting thousands.
As of December 2017, Venezuela had reported more than 500 cases (mainly in 5-19 year-olds) and an unspecified number of deaths, with conflicting information about shortages of vaccines and essential medicines and unsanitary living conditions.
In Yemen, entangled in a protracted conflict, more than 300 people – mainly under 20 years of age – are affected, with at least 35 deaths since September 2017. And in Bangladesh, trying to cope with 650,000 Rohingya refugees from neighbouring Myanmar, diphtheria has infected more than 2,000 and killed at least 20, with children under 15 disproportionately affected.
In each outbreak, crises with different causes (state failure, conflict, displacement) have disrupted or disabled already dysfunctional public health infrastructure and caused rapid resurgence of the disease. But this is not the first time diphtheria has been the harbinger of public health collapse. In the former Soviet Union, the number of diphtheria cases increased from 800 in 1989 (before the Soviet Union collapsed) to more than 50,000 by 1994. More than 4,000 children and adults died of the disease between 1990 and 1997.
As a bacterial infection, diphtheria spreads from person to person through coughing and sneezing, and affects the respiratory system with the risk that the bacteria could release a toxin which irreversibly affects cardiac and neurological systems.
The mainstay of treatment is prompt use of appropriate antibiotics and anti-toxin, but this is a scarce and expensive treatment. Diphtheria is highly contagious and under-vaccinated populations living in crowded unsanitary conditions facilitate the spread of large outbreaks. And it can be fatal, killing in approximately 10% of cases, sometimes more in young children, even when treated.
Highly effective, safe and cheap vaccines have been available for decades, and can virtually eliminate the disease. Prior to its introduction, the US reported approximately 20,000 diphtheria cases each year; but in the last decade in total, they reported fewer than five cases. But this is not a vaccine available only to high-income countries – globally 86% of children were vaccinated in 2016.
The resurgence of diphtheria is also not purely a consequence of the recent crises. Had populations been adequately vaccinated prior to the crises, the disease would not be expected to spread. What is happening reflects the combination of a longstanding failing public health system exacerbated by an acute crisis.
In Yemen for example, diphtheria vaccine coverage has only been around 70% in the last five years; Venezuela experienced coverage below 80% most years in the last decade – both levels well below what is required to achieve population protection.
Meanwhile, the Rohingya – a marginalized and discriminated community in Myanmar – have historically had limited access to health services in their home country, and therefore have low vaccine coverage. In the refugee camps across the border in Bangladesh, they are living up to 30 people per tent, facilitating transmission.
Poor living conditions, limited access to treatment, lack of sanitation and malnutrition make disease transmission and death even more likely, despite international humanitarian organizations such as UNICEF, the World Health Organization and GAVI acting rapidly to stop further spread (although Venezuela has refused international assistance so far).
In Bangladesh, a government-led vaccination campaign is targeting 255,000 children; in Yemen, three million children are scheduled to be vaccinated, and treatment in the form of antibiotic doses and diphtheria anti-toxins doses have been shipped, although this is being complicated by a Saudi-led blockade of essential goods in Yemen and a global shortage of anti-toxin.
Expensive and logistically complex
But these emergency responses are expensive, logistically complex, and potentially dangerous for healthcare workers who regularly come under attack in conflict zones. If stronger, more resilient healthcare systems were accessible to all, such responses would not be necessary.
The evidence of high vaccine coverage already in some of the world’s poorest countries demonstrates that providing population protection through vaccination is achievable and affordable even in low resource environments.
It is shameful that in 2017, so many people are still dying from an entirely preventable disease that should be fully consigned to history. The international community must work together to prevent tragedies such as Yemen, Bangladesh or Venezuela happening again by carefully balancing emergency response with investment in strong, resilient and universally accessible healthcare systems.
Dr Michael Edelstein, Consultant Research Fellow, Centre on Global Health Security and Dr Gayatri Amirthalingam, Consultant Epidemiologist, Public Health England.