On 10th November, 2017, a suspected case of diphtheria was reported at a Médecins Sans Frontières (MSF) clinic in Cox’s Bazar district, Bangladesh (Finger et al. 2019). A bacterial infection, diphtheria was a major cause of childhood illness and death in the early 20th Century, before a vaccine was developed in the 1920s, then included in the WHO’s Expanded Programme on Immunization in the 1970s.