Main messages

• diphtheria is a notifiable disease in the UK. Healthcare professionals have an important role to play in early recognition, treatment and vaccination of suspected diphtheria cases amongst new arrivals
• if a case is diagnosed, contact your 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
• in view of the increase in cases of diphtheria in newly arriving asylum seekers, population-based prophylaxis has been recommended as an interim control measure. This includes an offer of antibiotic prophylaxis and vaccination to asylum seekers in initial accommodation settings
• 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. The World Health Organisation reported that in 2021 there were approximately 8,638 diphtheria cases worldwide and the case fatality rate of respiratory diphtheria is 5 to 10%, even with treatment.

It 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 in 1957. Cases in recent years have been linked to foreign travel (C. diphtheriae) or to pet ownership (C. ulcerans).

Since June 2022 there has been an increase in confirmed cases of toxigenic diphtheria among migrants in Europe. The most common presentation is with cutaneous diphtheria, caused by a toxin-producing Corynebacterium diphtheriae. Respiratory presentations are also seen including cases of classical respiratory diphtheria with a membrane. Most cases diagnosed in England have arrived recently and are likely to have acquired their infection during their journey to the UK.

Respiratory symptoms and signs include:

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

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 case definitions in the supplementary national guidance noting the probable case definition has been expanded in this population (November 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 considered high risk for infectious diseases, including diphtheria.

Testing

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

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

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

Treatment

In line 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 DAT 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.

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

For guidance on immunisation of cases refer to section 2.6.5 in 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. When their immunisation status is uncertain or incomplete they should be brought up to date as per the UK schedule. UKHSA 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 status 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 supplementary guidance for diphtheria cases and outbreaks in asylum seeker accommodation settings.

During 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 have developed guidance for use by health protection teams to support the control and management of diphtheria in asylum seeker accommodation settings.

Further resources are available for asylum seeker settings:

• diphtheria disease and azithromycin patient group direction (PGD)
• data collection form for asylum seekers
• leaflets and vaccination and treatment record card
• warn and inform letter and factsheet