Monkeypox outbreak: what paramedics need to know

What is monkeypox?

Monkeypox is viral zoonotic disease (i.e. virus transmitted to human from animals) caused by the monkeypox virus. It is an Orthopoxvirus similar to the smallpox virus and was named when it was first discovered in monkeys in 1958 (Parker and Buller, 2013).

The first human case of monkeypox was identified in 1970 in the Democratic Republic of the Congo (DRC). It is an endemic disease in Central and West Africa where there is an ongoing outbreak (WHO, 2022b). Sporadic cases have also been identified in countries outside the endemic region with four cases identified in the UK since 2018 linked to travel to Nigeria, with onward transmission to three further cases within the UK (Adler et al, 2022). One of these was a healthcare worker, who likely became infected through contact with contaminated bedding (Vaughan et al, 2020).

Monkeypox has an incubation period of between 5 and 21 days. Symptoms in the first phase (the febrile prodrome) are usually fever, headache, chills, myalgia, lymphadenopathy, arthralgia, backache, and tiredness (UKHSA, 2022b). In the second phase, usually 1–5 days after the febrile prodrome, a rash may appear. The rash develops through sequential stages, starting with flat lesions which become raised, forming clear fluid-filled vesicles, then yellow fluid-filled pustules. Eventually lesions scab over, and the scabs will fall off (UKHSA, 2022b; WHO, 2022b).

Monkeypox outbreak in the UK

The majority of the recent cases in the UK and Europe do not have travel history to West or Central African countries (UKHSA, 2022c) and were predominantly, but not exclusively, found in gay, bisexual, or other men who have sex with men (GBMSM) (UKHSA, 2022c).

While epidemiological investigations are still ongoing as to the origins of this current outbreak, one possible explanation is that since the smallpox vaccine is known to provide some cross-reactive protection against monkeypox, cessation of smallpox vaccination after smallpox was eradicated means more people are susceptible, due to less immunity in the population (Rimoin et al, 2010).

Monkeypox became a ‘Notifiable Infectious Disease’ (NOID) in the UK on the 8 June 2022 (Lacobucci, 2022) and it should be managed as a ‘High Consequence Infectious Disease’ (HCID). (UKHSA, 2021).

UKHSA has produced guidance on the classification of suspected monkeypox cases as ‘possible’, ‘probable’ or ‘confirmed’.

Clinical management

NHS ambulance services and/or paramedics in primary care should initially assess the patients remotely via video assessment if possible (Association of Ambulance Chief Executives (AACE), 2022). They should advise a suspected case to contact their local sexual health clinic in the next 24 hours if they have a rash with blisters and they have been either in close contact, including sexual contact, with someone who has or might have monkeypox or have travelled to West or Central Africa in the past 3 weeks. They should be advised to call ahead to ensure they can be seen safely (NHS, 2022).

Although human-to-human transmission is uncommon, monkeypox may be transmitted via close direct contact (skin to skin), respiratory droplets and/or fomites. It is important for paramedics who provide face-to-face assessments and/or transportation for suspected/confirmed monkeypox patients to wear appropriate personal and protective equipment (PPE) to reduce the risk of being infected. Level 2 PPE (fluid repellent surgical facemask (FRSM), eye protection, apron and gloves) should be worn with possible/probable monkeypox cases and Level 3 PPE (FFP3 respirator, eye protection, a long-sleeved, fluid-repellent disposable gown, and gloves) should be worn with a confirmed case of monkeypox if the management of the case would require close clinical contact (AACE, 2022; UKHSA 2022b).

The clinical differential diagnosis that must be considered includes other rash illnesses, such as chickenpox, measles, bacterial skin infections, scabies, syphilis, and medication-associated allergies. It is worth noting that the rash of monkeypox can look similar to the chickenpox rash; however, the presence of lymphadenopathy can help distinguish the two (WHO, 2022b).

Clinical waste (including PPE worn) should be disposed of as per current guidelines and all clinical waste from a confirmed case should be treated as infectious clinical waste. It is worth noting that scabs are also infectious and care must be taken to avoid transmission through handling of bedding (UKHSA, 2022b).

The majority of cases experience a mild, self-limiting illness lasting 2–4 weeks (UKHSA, 2022b; WHO 2022b). The treatment is mainly supportive through management of symptoms/complications. However, there are some individuals, including young children and immunocompromised individuals, who may experience a more severe illness. Secondary infections can occur, including sepsis and encephalitis. Death can also result from the infection (WHO, 2022b).

The decision for conveyance to emergency departments (ED) should ideally be discussed with sexual health services (in hours) or imported fever services (out of hours). If conveyance is advised or deemed clinically necessary by the attending ambulance clinician, the receiving unit should be made aware of the possibility of monkeypox on arrival by the local procedures for pre-alert and by the driver on arrival of the ED before offloading the patient.

It is important that paramedics should advise any suspected monkeypox patients who are not treated in hospital to isolate to prevent further transmission until they have received negative laboratory results and/or until all the lesions have scabbed over, the scab falls off and intact skin is present. The scab itself may be infectious (UKHSA, 2022b; WHO, 2022b).

Summary

Monkeypox is a viral zoonotic disease for which human-to-human transmission is uncommon. Paramedics should consider the use of remote assessment if possible and other rash illnesses as differential diagnoses. The majority of cases experience a mild, self-limiting illness lasting 2–4 weeks and the treatment for patients is mainly supportive. Using appropriate PPE, minimising conveyance to ED unless clinically necessary and providing appropriate isolation advice could help to prevent further transmission of the disease in the UK.