Unrest in Myanmar in August 2017 resulted in the movement of over 700,000 Rohingya refugees to overcrowded camps in Cox's Bazar, Bangladesh. A large outbreak of diphtheria subsequently began in this population.
METHODS AND FINDINGS
Data were collected during mass vaccination campaigns (MVCs), contact tracing activities, and from 9 Diphtheria Treatment Centers (DTCs) operated by national and international organizations. These data were used to describe the epidemiological and clinical features and the control measures to prevent transmission, during the first 2 years of the outbreak. Between November 10, 2017 and November 9, 2019, 7,064 cases were reported: 285 (4.0%) laboratory-confirmed, 3,610 (51.1%) probable, and 3,169 (44.9%) suspected cases. The crude attack rate was 51.5 cases per 10,000 person-years, and epidemic doubling time was 4.4 days (95% confidence interval [CI] 4.2-4.7) during the exponential growth phase. The median age was 10 years (range 0-85), and 3,126 (44.3%) were male. The typical symptoms were sore throat (93.5%), fever (86.0%), pseudomembrane (34.7%), and gross cervical lymphadenopathy (GCL; 30.6%). Diphtheria antitoxin (DAT) was administered to 1,062 (89.0%) out of 1,193 eligible patients, with adverse reactions following among 229 (21.6%). There were 45 deaths (case fatality ratio [CFR] 0.6%). Household contacts for 5,702 (80.7%) of 7,064 cases were successfully traced. A total of 41,452 contacts were identified, of whom 40,364 (97.4%) consented to begin chemoprophylaxis; adherence was 55.0% (N = 22,218) at 3-day follow-up. Unvaccinated household contacts were vaccinated with 3 doses (with 4-week interval), while a booster dose was administered if the primary vaccination schedule had been completed. The proportion of contacts vaccinated was 64.7% overall. Three MVC rounds were conducted, with administrative coverage varying between 88.5% and 110.4%. Pentavalent vaccine was administered to those aged 6 weeks to 6 years, while tetanus and diphtheria (Td) vaccine was administered to those aged 7 years and older. Lack of adequate diagnostic capacity to confirm cases was the main limitation, with a majority of cases unconfirmed and the proportion of true diphtheria cases unknown.
CONCLUSIONS
To our knowledge, this is the largest reported diphtheria outbreak in refugee settings. We observed that high population density, poor living conditions, and fast growth rate were associated with explosive expansion of the outbreak during the initial exponential growth phase. Three rounds of mass vaccinations targeting those aged 6 weeks to 14 years were associated with only modestly reduced transmission, and additional public health measures were necessary to end the outbreak. This outbreak has a long-lasting tail, with Rt oscillating at around 1 for an extended period. An adequate global DAT stockpile needs to be maintained. All populations must have access to health services and routine vaccination, and this access must be maintained during humanitarian crises.
At the time of writing, many people around the world are feeling the pain, disruption, and devastating health consequences driven by climate change. The world has been shocked by the widespread flooding in Europe and the consecutive catastrophic hurricanes in North America. Yet far less attention is given to the impacts of climate change in places where Médecins Sans Frontières (MSF) works, such as Central African Republic, Chad, Côte d’Ivoire, Democratic Republic of Congo, Myanmar, Niger, Nigeria, and South Sudan. In 2024, these populations have likewise been affected by devastating floods, many of them not for the first time.
Although immediate impacts like injury, displacement, and limited access to healthcare may be similar worldwide, the compounding crises that follow and the capacity to recover from these vary significantly. Individuals in low-resource and humanitarian settings face significant health threats while contributing the least to global emissions. These regions are often vulnerable to climate hazards and possess low adaptive capacity, increasing people’s susceptibility to the negative impacts of climate change.
In this brief, drawing on evidence from indicators in the 2024 report of the Lancet Countdown on Health and Climate Change, MSF teams present examples of how climate change and environmental degradation are making provision of assistance more difficult by amplifying health and humanitarian needs and by further complicating interventions. It also highlights activities that respond to the climate crisis using a three-pillar approach: mitigating MSF’s environmental footprint, adapting healthcare delivery and emergency response to the current and future realities of climate change, and advocating for those impacted.
The complexity of climate change and environmental degradation, coupled with highly politicised and siloed global response efforts often make it insufficiently clear to health and humanitarian implementing partners that every issue is part of a continuous process, where each component informs the others. In this brief, MSF staff outline six focus areas where teams are engaged in developing environmentally-informed health and humanitarian interventions, emphasising their interdependence, and how failure to act on one issue not only impedes progress on that specific component but also affects the entire sequence of subsequent actions.