Introduction
Monkeypox (MPX) is a zoonotic disease caused by an Orthopoxvirus belonging to the same genus as smallpox. The MPX virus was discovered in 1958,1–4 with the first human infection identified in 1970 in the Democratic Republic of Congo (DRC).5 Since then human MPX has mostly been reported in Central and Western African countries. Two distinct genetic clades of the virus have been identified—the Congo Basin and the West African clades, with a case fatality rate of 1%–3.6% and 10.6%, respectively, estimated in earlier outbreaks.6 The number of human MPX cases has been rising since the 1970s, with the highest increases reported in the DRC and an increase in travel-imported cases outside of Africa. In 2003, 37 confirmed cases were detected in the USA, linked to contact with pet prairie dogs infected by rodents from Africa.7 8 This was followed by sporadic travel imported cases in the UK (2018 and 2021), Israel (2018) and Singapore (2019).9–12 From December 2021 to 1 May 2022 there were 1315 cases and 57 deaths reported from four countries in Africa.6
The ongoing outbreak in 2022 is the first documented multicountry outbreaks in non-endemic countries, with 257 confirmed cases in 23 countries reported as of 26 May 2022.13 14 The current outbreaks are assessed by the WHO as medium risk for the general population with low risk for pandemic potential. MPX presents as a vesicular–pustular illness, which may be preceded by fever, headache, tonsillitis, cough, myalgia and fatigue.15 Fever can be absent. Lymphadenopathy if present may distinguish it from chickenpox and smallpox.16 17 Complications include painful lesions, secondary infections, bronchopneumonia, encephalitis, keratitis and psychological symptoms.15–18 Younger children and pregnant women are at higher risk of severe disease.15 The incubation period is up to 21 days. Interactions with infected animals and individuals is associated with risk of infection.19 Human-to-human transmission occurs through direct contact (body fluids, skin lesions, mucosal surfaces, respiratory droplets), indirectly (contaminated objects) and vertically from mother-to-fetus through the placenta.18 20 21 PCR is the preferred diagnostic test.22 Due to Orthopoxviruses serological cross-reactivity, antigen and antibody detection methods do not provide MPX-specific confirmation. Previous smallpox vaccination may lead to false positive results.18 The smallpox vaccine has been estimated to be 85% protective against MPX.23 24 The first-generation live smallpox vaccine is not recommended in pregnancy or in people with immunosuppression.25 26 Newer third-generation live, non-replicating vaccines, are approved in certain regions for smallpox and MPX in adults.27 None are part of routine vaccination programmes, and not readily available for public use globally.28
Therapeutic options are limited. Tecovirimat is licenced in some countries for the treatment of smallpox in adults and children (>13 kg),29 and MPX during outbreaks.17 Two other treatments; cidofovir and brincidofovir have been shown to be active against poxviruses,30–32 with cidofovir having broad-spectrum activity against DNA viruses, including herpesviruses, adenoviruses, polyomaviruses, papillomaviruses and poxviruses.31 Both have been shown efficacy in in vitro and animal studies but data on treatment in humans with MPX is limited,32 and they are only authorised for use in certain countries.
Even when the evidence base is limited, clinical management guidelines are important tools for guiding clinical decision-making, and standardising the best available care between sites.33–35 Guidelines must be readily available, of good quality and inclusive of vulnerable patient groups. Standardisation of care will benefit patients and can also facilitate the implementation of needed multisites trials for therapeutics and vaccines. The increase in MPX cases in recent decades highlights the need to ensure that clinicians worldwide have access to clinical management guidelines to guide treatment, to benefit patient care and outcomes. This review aims to assess the availability, quality, scope and inclusivity of clinical guidelines for MPX.