**Note: the release below from the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID 2023, Copenhagen, 15-18 April). Please credit the conference if you use this story**
Various European countries experienced outbreaks of diphtheria mostly linked to incoming migrants.
Europe
Dr Helena Seth-Smith (University of Zurich), Dr Sylvain Brisse (Institut Pasteur - Paris (France) and collaborators from across Europe including the European Centres for Disease Control and Prevention (ECDC) assessed cases of diphtheria in migrants that had arrived in 10 European countriesSwitzerland (52 cases), Germany (118), UK (59), Austria (69), France (30), Belgium (21), Norway (8), The Netherlands (5), Italy (3), and Spain (1).
For their short report, click here
Dr Helena Seth-Smith, University of Zurich, Swtizerland. E) hsethsmith@imm.uzh.ch
Dr Sylvain Brisse, Institut Pasteur, Paris, France. T) +33 6 77 94 65 34
E) sylvain.brisse@pasteur.fr
This press release is based on abstract 2670 at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) annual meeting. The material has been peer reviewed by the congress selection committee. The research has been not yet been submitted to a medical journal for publication.
For full poster, click here
UK
Linked to an increase in migrant arrivals via small boat in the Summer of 2022, the UK experienced a sharp increase in diphtheria cases caused by toxigenic Corynebacterium diphtheriae last year, recording 73 when the annual average for previous years (including cases due to toxigenic C. ulcerans) was 12 cases. A further single case has been recorded in 2023.
The UK Health Security Agency (UKHSA) has two abstracts and posters containing all the relevant information about the outbreak (see links below) Steps taken by UK health authorities included recommending mass administration of antibiotic prophylaxis and vaccination in initial reception centres and other accommodation settings for recent arrivals. UKHSA preliminary data as of 18 January 2023 estimates approximately 40% and 88% of eligible arrivals received prophylactic antibiotics and vaccination, respectively, since implementation.
For further information on diphtheria in the UK, please contact the UKHSA Press Office. T) +44 20 7654 8400 E) ukhsa-pressoffice@ukhsa.gov.uk
Alternative contact Tony Kirby in the ECCMID Media Centre. T) +44 7834 385827 E) tony.kirby@tonykirby.com
This press release is based on abstract 5308 and late breaker abstract LB103 at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) annual meeting. The material has been peer reviewed by the congress selection committee. The research has been not yet been submitted to a medical journal for publication.
For full 5308 abstract click here, for full poster click here
For full LB103 abstract click here, for full poster click here
Twitter (for when embargo lifts): @escmid #ECCMID2023
Germany
In Germany, experts are continuing to track an outbreak of imported diphtheria that began in Summer 2022, and as of March 2023 affected 169 migrants that had arrived in Germany, mostly from Afghanistan and Syria. This is despite the fact that diphtheria incidence and vaccination coverage in Afghanistan and Syria has remained mostly unchanged over the last few years
Whole genome sequencing and phylogenetic analysis at the National Consiliary Laboratory for Diphtheria (Oberschleissheim, Germany) and migration route analysis at the Robert Koch Institute, Berlin, Germany, suggests that migrants affected had acquired toxigenic Corynebacterium diphtheriae neither in their home country nor in Germany, but in between while migrating – mainly along the Balkan route which includes, among other countries, Albania, Bosnia and Herzegovina, Bulgaria, Croatia, North Macedonia, Romania, Serbia, and Slovenia.
Franziska Badenschier, based at the Department for Infectious Disease Epidemiology at the Robert Koch Institute, and her colleagues were able to detect this outbreak within six weeks of the first cases being reported. It then became clear that this outbreak in Germany was part of an international outbreak in Europe.
Badenschier also explains that some cases were initially thought to be mpox, until testing dismissed this and confirmed the cases as diphtheria. She and her colleagues conclude that, for better and more timely diagnosis of diphtheria, clinicians, microbiologists, and institutions working with migrants shall raise awareness and intensify sample collection from wounds with subsequent laboratory diagnostics.
Since the outbreak is ongoing and the sources of it have not been identified yet, Badenschier and her co-authors suggest active case finding and outbreak detection in countries along the Balkan route.
Franziska Badenschier, Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany. T) +49 (0)30 18754-2069 E) badenschierf@rki.de
This press release is based on late breaker abstract LB096 at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) annual meeting. The material has been peer reviewed by the congress selection committee. The research has been not yet been submitted to a medical journal for publication.
For full poster, click here
Austria
Population study shows one third of people not adequately protected against diphtheria
Tests on blood samples of some 16,000 people in Austria show one third of the population have insufficient immunity against diphtheria. The research is presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID 2023, Copenhagen, 15-18 April) and is by Prof Ursula Wiedermann-Schmidt and Angelika Wagner, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Australia, and colleagues.
Various European countries, including the UK, Germany and Austria, reported an unusual increase in diphtheria cases in 2022, with around 80% of these cases in migrants arriving in those countries from countries such as Syria and Afghanistan. Austria reported 62 cases of diphtheria in 2022. The authors, concerned about possible onward transmission of this disease among the general population, aimed to estimate the level of immunity (seroprotection) against diphtheria among people living in Austria.
The authors analysed antibody concentrations against diphtheria toxoid from all individuals requesting voluntary antibody testing at the Austrian reference laboratory at the Institute of Specific Prophylaxis and Tropical Medicine (ISPTM) at the Medical University of Vienna between March 1, 2010 and January 31, 2022. Individuals requesting such testing are usually doing so to check their immunity to see if they need a booster to maintain protection.
In total, the authors included diphtheria-toxoid (DT) specific antibody concentration results from 15 852 individuals and of those 12 539 individuals also requested determination of tetanus-toxoid (TT) specific antibodies. Individuals requesting antibody testing were mainly located in the eastern Austrian provinces (Table 1), with around half the total participants coming from the Vienna Province. Antibody concentrations of under 0.01 IU/mL were considered as non-protective; between 0.01 and 0.1 IU/mL as inadequately protective and 0.1 IU/mL and above as adequately protective.
When looked at as three distinct age groups, the results showed individuals aged 60 years and over had the lowest antibody concentrations compared to those under 15 years and those between 15 and 60 years (Figure 2). Those aged under 15 years also had lower protection when compared with those aged 15-60 years. Participants aged above 60 years had the highest proportion of non-protected (4.8%) and insufficiently protected individuals (40.7%) (Figure 3).
Overall, 33% of individuals lacked seroprotection against diphtheria (Figure 3, Table 3). When stratified further according to age (0-6 years 6-15 years, 15-25, 25-35, 35-45, 45-55, 55-65, 65-75, and above 75 years) and sex, the data showed those aged 6-15 years and age groups 55 years and over as having the lowest protection.
Regarding tetanus antibody levels, young individuals had lowest median tetanus antibody concentrations (compared to 15-60 years old and 60 years and over). Interestingly, tetanus levels did not differ between the 15-60 years group and those over 60 years old.
The authors conclude: “Our data show insufficient seroprotection against diphtheria in all age groups, while seroprotection rate against tetanus is higher throughout all age groups. Thus, awareness for regular booster vaccination with combination vaccines (including diphtheria, tetanus and whooping cough) needs to be urgently increased as recommended every 10 years (5 years in those aged over 60 years), according to the Austrian National Immunization Plan. The fact that tetanus antibody levels and seroprotection are generally higher and longer lasting, illustrates the necessity to reintroduce of monovalent diphtheria vaccines for diphtheria catch-up vaccination. In addition, the use of higher diphtheria vaccine doses - as used for primary immunisation – for adult booster vaccinations, might be an option to close gaps in diphtheria seroprotection.”
Prof Ursula Wiedermann-Schmidt, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Austria. T) +43 1 40160 38290 E) ursula.wiedermann-schmidt@meduniwien.ac.at
Angelika Wagner, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Austria. Please email to arrange interview. E)
This press release is based on abstract 6915 (Late breaker LB119) at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) annual meeting. The material has been peer reviewed by the congress selection committee. The research has been not yet been submitted to a medical journal for publication.
For full abstract click here
For full poster click here