Main messages

The main messages are:

• diphtheria is a notifiable disease in the UK.UK
• healthcare Healthcare professionals havehave an an important rolerole to to play in early recognition, treatmentisolation andand treatment of vaccination of suspected diphtheria cases particularly amongst new arrivalsarrivals and in settings where there is a higher risk of transmission.
• all cases are notifiable on clinical suspicion, including both respiratory and cutaneous forms of the infection – if ayou casesuspect isa diagnosed,case, contact your local local UK Heath Security Agency (UKHSA) health protection team
• diphtheria may present with respiratory symptoms and/or skin lesions. Respiratory presentations may be more common than expected in some migrants compared to the general UK population due to low vaccination rates
• inrates. viewMany ofmigrants thehave increaseexperienced inlong casesjourneys ofprior diphtheriato inreaching newlythe arrivingUK asylumand seekers,often population-basedhave prophylaxispoor skin integrity. C. diphtheriae has been recommendedfound to colonise or infect long standing wounds, and there is often co-infection with other organisms such as anGroup interimA controlStreptococcus measure.or ThisStaphylococcus includesaureus
• all annew offerarrivals ofshould antibiotichave prophylaxistheir immunisation status checked and vaccinationthey should be brought up to asylumthe seekersdate inwith initialany accommodationvaccines settingsthey have missed or where their vaccination status is uncertain
• staff and healthcare workers involved in the care of recent arrivals should ensure they are up to date with their immunisations as per the UK schedule

Background

Diphtheria is an acute bacterial disease caused by the Corynebacterium species.species, TheC. diphtheriae and C. ulcerans. The World Health OrganisationOrganization reported reported that in 20212024 there were approximately 8,63825,146 diphtheria cases worldwide and the case fatality rate of respiratory diphtheria iscan 5be to30% 10%,for evenunvaccinated withindividuals, without proper treatment.

ItDiphtheria was once one of the most feared childhood diseases in the UK, with more than 61,000 cases and 3,283 deaths in 1940. However, following the introduction of mass vaccination, this was dramatically reduced, with only 38 cases and 6 deaths reported inby 1957. National surveillance for toxigenic diphtheria is well established and between 1986 until 2023 there have been 233 toxigenic diphtheria cases in England and Wales with the annual number of cases varying from one to 87. Cases in recent years have been linked to foreign travel (C.(C. diphtheriae)diphtheriae) or to pet ownership (C. ulcerans).(C. ulcerans).

Since June 20222022, there has been ana increaserise in confirmedtoxigenic C. diphtheriae cases among asylum seekers in Europe and the UK. An outbreak of toxigenic diphtheria was reported among migrants in Europe.Europe in June 2022 and cases were seen in those arriving by small boats to the UK. The most common presentation iswas with cutaneous diphtheria, causedbut byrespiratory a toxin-producing Corynebacterium diphtheriae. Respiratory presentations arewere also seen including casesa small number of cases with classical respiratory diphtheria with a membrane. Most cases diagnosed in England havehad arrived very recently and areall likelywere considered to havehave acquired their acquired their infection during their journey to the UK.UK. Despite higher arrivals of asylum seekers by small boats in 2024 compared with 2022 and 2023, the level of risk of diphtheria appears to have reduced.

Symptoms

The incubation period for diphtheria is usually 2 to 5 days, but may be longer, with reports of incubation lasting up to 10 days. Respiratory symptoms and signs include:include: 

• presence of sore throatthroat 
• feverfever 
• adherent greyish membrane (bleeds when manipulated or dislodged) of the tonsils,tonsils, pharynx, or pharynx or nose (but noting a membrane may not always be present)present) 
• other presentations: endocardial, optic, conjunctival, genital, laryngeal

Cutaneous skinsymptoms:

• chronic lesionsnon-healing sores or shallow ulcers
• dirty grey membrane, eschar, slightly raised
• usually on exposed limbs (legs)

As the disease is increasingly rare, most clinicians will not have encountered a case before and therefore may miss the clinical diagnosis. Clinicians should have a high index of suspicion for diphtheria in individuals presenting with compatible symptoms. Cases among migrants should be classified according to the the case definitions in the supplementary national guidance noting noting the probable case definition has been expanded in this population (November 2022).2022). 

Due to low vaccine uptake reported in this population, the complex health needs of many residents and their mixing patterns, accommodation settings for migrants may be consideredconsidered high highrisk for risk for infectious diseases, including diphtheria.diphtheria. 

Transmission

The most common mode of transmission of C. diphtheriae is droplet spread from a person with respiratory diphtheria or direct contact with cutaneous lesions or infected secretions (respiratory or cutaneous).

Testing

Appropriate swabs should be collected for all clinically suspected cases of diphtheria irrespective of clinical presentation and before starting treatment with antibiotics:antibiotics (see national guidance): 

• nose and throat swabs should be taken for all suspected cases (including screening for respiratory carriage in cutaneous cases)cases) 
• skin swabs of wounds and lesions (if present)present) 
• where a membrane is present, swabs from underneath the membrane or a piece of membranemembrane 

Diphtheria is a notifiable disease in the UK. If a case is diagnosed, contact your local local UKHSA health health protection team.

Treatment

In line with with national guidance, all clinically suspected cases of diphtheria who present with respiratory symptoms and/or large cutaneous lesions (that is, greater than 2 cubic centimetres) should be promptly assessed by a clinician with advice from an infectious diseases specialist, for treatment with diphtheria anti-toxin (DAT).). 

Treatment with with DAT should should not be delayed and should be undertaken in a hospital setting. Management should be based on clinical assessment, even in the absence of laboratory confirmation and where there is no alternative diagnosis, particularly in those who have received antibiotic prophylaxis.prophylaxis. 

Refer to section 2.6.4 and 2.7 of the the national guidance for for information on the administration of antibiotics. A small number of multi-drugmulti-drug-resistant isolates resistant isolates have been reported in the European literature and local laboratories have been advised onon minimum requirements minimum requirements for antibiotic susceptibility testing. Advice on further antibiotic therapy should bebe sought from sought from the local microbiologistmicrobiologist in in the event ofof treatment treatment failure or failure to clear carriage of the organism.organism. 

For guidance on immunisation of cases refer to section 2.6.5 in the the diphtheria public health guidance.

Prevention and control

The most important aspects of preventing and controlling diphtheria in your area are immunisation and infection prevention and control.

Immunisation

An immunisation history should be taken from all migrants.migrants When When their immunisation status is uncertain or incomplete they should be brought up to date as per the UK schedule. schedule. UKHSA have  have guidance to support healthcare professionals with immunisation assessments.. 

All staff and healthcare workers involved in the care of recent arrivals should have their immunisation statusstatus reviewed and reviewed and catch-up immunisations arranged if their status is uncertain or incomplete (as above).

Infection prevention and control, including the appropriate use of personal protection equipment

Guidance on the management of suspected cases, their close contacts and their environment may be found in the the supplementary guidance for diphtheria cases and outbreaks in asylum seeker accommodation settings.

During

Resources

• Supplementary the period of high prevalence of diphtheria in newly arriving asylum seekers, prophylactic measures have been recommended by UKHSA, including a course of prophylactic antibiotics and a diphtheria containing vaccine for new arrivals. These recommendations will remain in place until October 2023 but will be subject to regular review. Further detail may be found in Public health control and management of diphtheria in England: supplementary guidance for cases and outbreaks in asylum seeker accommodation settings.

  Resources

  UKHSA

• Public have developed guidance for use by health protection teams to support the control and management of diphtheria in asylumEngland: seeker2025 accommodation settingsguidelines.

  Further

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