The evidence of occupational infections and a quantification of the risk of contagion in healthcare workers are mostly unknown, since the studies collecting evidence on these topics are anecdotal. Documented contagion in healthcare settings has been reported by Vaughan ^[1][15], before the current monkeypox outbreak. The infection occurred in a healthcare assistant wearing disposable aprons and gloves, almost two weeks after contact with an infected patient and nevertheless having received a post-exposure vaccination (>4 days after the contact). The only exposure risk identified was the changing of potentially contaminated bedding. Four other subjects of 134 identified among the healthcare assistant’s contacts became infected with monkeypox. A study dating back to 2005 ^[2][16] reported the surveillance data of 81 healthcare workers exposed to three monkeypox patients, with one of them requiring critical pediatric care. HCW exposure was defined as entrance into the immediate care area (2 m radius surrounding the patient) and protected exposure was defined as exposure with the use of personal protective equipment recommended for droplet precautions (gloves, gown, and a surgical or N95 mask). A total of 70% of HCWs had at least one unprotected exposure, but none reported symptoms consistent with the monkeypox illness. Another occupational transmission of monkeypox was described in the Central African Republic in 2016 ^[3][17], following a pediatric case. In fact, it was reported that five individuals outside the family of the child were infected with developed monkeypox: one hospital nurse, one doctor, one nurse who accompanied the patients during the transfer to the hospital, and two individuals who transported the patients to the hospital. Security measures were reinforced only after the first nurse became ill. In an effort to quantify the phenomenon of occupational infection, between 2010 and 2014, 1266 suspected monkeypox cases were investigated in the Tshuapa region in the Democratic Republic of Congo ^[4][18], of whom eleven worked as healthcare workers. Among the 699 confirmed cases, six confirmed cases of monkeypox among HCWs represented a proportion of 0.9% (range of 0.3–3.1% by year), yielding an estimated annual HCW incidence rate of 17.4/10,000, which is much more elevated than that of the general population. In more recent studies conducted in high-income countries ^[5][6][7][8][19,20,21,22], several HCWs were identified as contacts, but most were classified as low risk. Notably, three studies reported monkeypox cases during the COVID-19 pandemic and no secondary occupational infection was reported following the active surveillance. A recent study ^[9][23] assessed the viral load on surfaces in healthcare facilities where two patients affected by monkeypox were hospitalized: all surfaces directly touched by the patients’ hands showed viral contamination, with the highest loads detected in bathrooms. Monkeypox virus DNA was also found on the patient’s room surfaces, on fabrics used by patients, and also in the anterooms, even if with a lower viral load.

Exposed workers should be evaluated regarding their risk and receive counselling on self-monitoring, isolation, and the prompt reporting of symptoms; aerosolizing procedures, such as shaking bed sheets, should be considered high risk. Exposed healthcare workers should undergo a 21-day active surveillance to cover the incubation period. Outpatient settings should also be provided, with adequate PPE given the current manifestations of the disease. Post-exposure vaccinations can be given with the available variola vaccines (VARV), ideally within four days of the exposure and up to fourteen days past exposure ^[5][6][10][19,20,24].

Following the recent outbreak, the centers of disease control, both American and European, as well as national Ministries of Health have provided guidelines on the protective measures to be followed in healthcare settings to reduce the risk of contagion and the spread of the virus. There is a large consensus that appropriate airborne-precautionary PPE is needed, including a fit-tested filtering facepiece respirator (for example, an N95 respirator) or a powered air-purifying respirator, gloves, and gowns ^[10][11][24,25]. A patient’s skin lesions should be covered with a bandage or gauze. Since poxviruses are very stable and may remain contagious in the environment, disinfectants should be used for the cleaning and disinfection of high-touch surfaces, and procedures (such as sweeping, dry dusting, or shaking bed linens) that may aerosolize virus particles should be avoided ^[12][26]. Linens should be removed carefully and washed at high heat or discarded. In a previous monkeypox outbreak in Nigeria, several preventive measures took place, including reserving an entire ward for the treatment of infected patients ^[13][27]. Generally, it is recommended to place the patients in dedicated rooms, if available with negative pressure ^[11][12][25,26]. In surgical settings, preventive measures such as those adopted for COVID-19 should be implemented. Aerosol-generating procedures and several surgical procedures (e.g., laparoscopic surgery, intubation) can generate aerosols infected with the virus. Therefore, there is a need to apply procedures to reduce the aerosol production during surgeries, such as rapid sequence intubation, limiting the use of equipment such as harmonic scalpels, utilizing smoke evacuation systems, and others ^[12][26].

Education and training on recognizing the disease is crucial ^[10][24]. Recently, Koenig et al. ^[14][28] presented a framework tool to be used by emergency department policymakers, educators, and clinicians on the frontline. It is based on the “identify–isolate–inform” procedure and should especially help prehospital workers: patients are identified as potentially exposed or infected after an initial assessment of risk factors with associated signs and symptoms. Prehospital workers must immediately don personal protective equipment (PPE) and isolate infectious patients; the exchange of information with agency infection control offices must also take place as quickly as possible. In previous African monkeypox outbreaks ^[13][15][27,29], the implemented measures included workshops to inform and educate healthcare staff about monkeypox; clinicians were trained on the various aspects of standard precautions of infection control, the use of personal protective equipment, and healthcare waste management.

One of the challenges in preventing monkeypox is the lack of knowledge about the disease among healthcare workers. In regions such as Europe or Southeast Asia, where cases of monkeypox never occurred until a few months ago, physicians may encounter some struggle in recognizing and treating monkeypox, which is a fundamental part of the prevention strategy. In a study conducted in Indonesia in 2020 among general practitioners ^[16][30], 10.0% and 36.5% of them had a good knowledge using an 80% and 70% cutoff point for the knowledge domain, respectively. Younger doctors had better knowledge, but the overall knowledge of monkeypox was low in all groups. A more recent study conducted among 163 general practitioners, public health doctors, and occupational physicians in Italy in May 2022 ^[17][31] demonstrated that the knowledge status for monkeypox infections was quite unsatisfying, with substantial knowledge gaps in all aspects of the disease and with a substantial overlooking of monkeypox as a pathogen, particularly when compared to SARS-CoV-2, TB, HIV, and HBV. However, the attitude toward vaccination was positive, despite concerns expressed by the WHO in 2019 about vaccine hesitation, which was ranked among the 10 threats to global health. In Indonesia, even before the COVID-19 pandemic, over 90% of doctors participating in a cross-sectional study about the attitude toward monkeypox vaccination were willing to be vaccinated ^[18][32].

In the literature research, the biological risk linked to the monkeypox virus was also identified in occupational settings dealing with pets and wildlife animals. Since monkeypox has a zoonotic transmission, veterinarians, pet staff, and other categories of workers with close contact with animals can be considered at high risk. In 2003, an outbreak of monkeypox virus infections occurred in the US, and this was the first outbreak recognized outside Africa. African rodents, which were identified as the primary carriers, had been housed with prairie dogs, which were subsequently distributed as household pets. Occupationally, transmitted infections occurred in twelve veterinary staff, two pet store employees, and two animal distributors. Working directly with animal care, being involved in prairie dog examination, caring for an animal within 6 feet of an ill prairie dog, and feeding an ill prairie dog were all activities associated with a higher risk of contracting the disease ^[19][33]. Human contact with wildlife is a major pathway for emerging and endemic infectious diseases, with 62% of all newly emerging infectious diseases being zoonotic, and monkeypox is one of them. In working sectors dealing with wildlife, such as the bushmeat trade, which is often illegal but very common in several African countries, knowledge regarding zoonosis and safety practices are fundamental to reduce the risk of exposure. In a study conducted regarding attitudes, practices, and zoonoses awareness of hunters and meat cookers in Uganda in 2020, only 62% of those interviewed acknowledged monkeypox for its zoonotic potential ^[20][34]. With a rise in the number of monkeypox cases, infected workers could contaminate the workplace, not only in healthcare settings, but also in offices. A revelation of viral load was made in an office where a patient worked during the prodromal phase of the illness. Low, but still present, traces of the virus were detected on a few superficies (3/34), demonstrating that contamination, although very limited, can occur in workplace environments, and accordingly, appropriate cleaning and decontamination measures should be considered in such situations ^[21][35].