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

Abstract

The introduction of treatment and systematic vaccination has significantly reduced diphtheria mortality; however, toxigenic strains continue to circulate worldwide. The emergence of an indigenous diphtheria case with fatal outcome in Greece, after 30 years, raised challenges for laboratory confirmation, clinical and public health management. Toxigenic Corynebacterium diphtheriae was isolated from an incompletely vaccinated 8-year-old boy with underlying conditions. The child passed away due to respiratory distress syndrome, before the administration of diphtheria antitoxin (DAT). All close contacts in family, school and hospital settings were investigated. Pharyngeal swabs were obtained to determine asymptomatic carriage. Chemoprophylaxis was given for 7 days to all close contacts and a booster dose to those incompletely vaccinated. Testing revealed a classmate, belonging to a subpopulation group (Roma), and incompletely vaccinated, as an asymptomatic carrier with an indistinguishable toxigenic strain (same novel multilocus sequence type, designated ST698). This case highlights the role of asymptomatic carriage, as the entry of toxigenic strains into susceptible populations can put individuals and their environment at risk. Maintenance of high-level epidemiological and microbiological surveillance, implementation of systematic vaccination in children and adults with primary and booster doses, availability of a DAT stockpile, and allowing timely administration are the cornerstone to prevent similar incidents in the future.

Diphtheria and Tetanus Immunity Status among Greek Adults: Results from a Nationwide Seroprevalence Study

“…The outbreak in the former Soviet Union in the recent past was caused by a number of circumstances, including a lack of population immunity, a weak socioeconomic infrastructure and a delayed public health response [36,37]. Greece has a low overall incidence and a high childhood immunization rate against tetanus and diphtheria toxoids [4,5]. Compared to booster vaccinations for the adult population [14], Greece has a higher vaccination rate for newborns [3], including both the first and third doses of the diphtheria, tetanus toxoid and pertussis vaccines.…”

“…According to the European Centre for Disease Prevention and Control (ECDC), 281 cases were reported in Europe in 2022. More specifically, the majority of cases were in Germany (206), though cases also occurred in Belgium (37), Czechia (10), Slovakia (9), the Netherlands (9), Sweden (5), Latvia (3), Norway (1) and Spain (1). Furthermore, two deaths, reported in 2023, occurred in Belgium and Latvia [3].…”

“…Furthermore, two deaths, reported in 2023, occurred in Belgium and Latvia [3]. Greece has been proclaimed diphtheria free since 1994 since the last autochthonous case of the disease was detected in 1982 [4,5]. The latest recorded case of diphtheria occurred in Greece in November 2019 and affected an 8-year-old boy who had pulmonary hypertension and mosaic Down syndrome as underlying disorders [5].…”