A case of respiratory toxigenic diphtheria: contact tracing results and considerations following a 30-year disease-free interval, Catalonia, Spain, 2015

Abstract

In May 2015, following a 30-year diphtheria-free interval in Catalonia, an unvaccinated 6-year-old child was diagnosed with diphtheria caused by toxigenic Corynebacterium diphtheriae. After a difficult search for equine-derived diphtheria antitoxin (DAT), the child received the DAT 4 days later but died at the end of June. Two hundred and seventeen contacts were identified in relation to the index case, and their vaccination statuses were analysed, updated and completed. Of these, 140 contacts underwent physical examination and throat swabs were taken from them for analysis. Results were positive for toxigenic C. diphtheriae in 10 contacts; nine were asymptomatic vaccinated children who had been in contact with the index case and one was a parent of one of the nine children. Active surveillance of the 217 contacts was initiated by healthcare workers from hospitals and primary healthcare centres, together with public health epidemiological support. Lack of availability of DAT was an issue in our case. Such lack could be circumvented by the implementation of an international fast-track procedure to obtain it in a timely manner. Maintaining primary vaccination coverage for children and increasing booster-dose immunisation against diphtheria in the adult population is of key importance.

A patient with respiratory toxigenic diphtheria in Greece after more than 30 years

“…This case was not an unexpected event and it is not unique, even for non-endemic European countries. Similar cases have been described recently in unvaccinated children with a fatal outcome; one in a 6-year-old child in Spain [29] and the other in a 3-year old child in Belgium [17].…”

Whole Genome Sequencing for Surveillance of Diphtheria in Low Incidence Settings

“…In this outbreak, a high proportion of adults were affected, potentially due to disruption of health services resulting in poor vaccine coverage (114, 115) and reduced “natural” exposure over the preceding decades, resulting in antibody titers below protective levels (116–118). In recent years, multiple outbreaks, or potential transmission clusters have been reported in: Bangladesh (119, 120), Brazil (121), Colombia (122), Germany (30, 35), India (123–125), Indonesia (126), Laos (127), Norway (128), Nigeria (129), Poland (130), Spain (38), South Africa (36, 131), Syria (132), Switzerland (31), Thailand (114), the United Kingdom (37), Venezuela (133, 134), and Yemen (135). The global list of affected countries indicates that (i) the disease is remains poorly controlled, (ii) the main burden lies in low-income countries, and (iii) local and global surveillance should be intensified in order to better control the disease.…”

“…For nearly two decades, in most high-income countries, cases have been reported rarely, occasionally in travel returners (20–24), drug users and homeless people (25–29). In the last few years, in contrast, cutaneous, and respiratory infections have predominantly been reported in refugees (16, 30–38).…”

Fatal respiratory diphtheria in a visitor to Canada

“…Close contacts are defined as household members, persons who have had close face-to-face contact to a case such as intimate contact and health care workers exposed to oropharyngeal secretions from the case, following the same principles as contact management for invasive meningococcal disease. 11 , 12 In a case report of respiratory diphtheria, subsequent transmission from an asymptomatic carrier was identified after additional contact follow-up activities. 11 …”

“…Recent case reports from nonendemic countries have described both toxigenic respiratory and cutaneous diphtheria among returning travellers, visitors, immigrants and refugees. 11 , 12 In patients presenting with respiratory distress, clinicians should consider the diagnosis of diphtheria, particularly among recent travellers or immigrants from endemic areas. Immunization status of newcomers and frequent travellers should be assessed to ensure individuals are up to date.…”