Monkeypox is a viral infection transmitted from animals to humans, caused by the monkeypox virus belonging to the family Poxviridae (the same family as smallpox).

Although the disease has been around for a long time and is quite widespread in parts of Central and West Africa, it was only on July 23, 2022, that the World Health Organization (WHO) declared monkeypox to be a Public Health Emergency of International Concern (PHEIC). But what is monkeypox, what are the symptoms, and why is its presence now considered a matter of concern? To find out more about this disease, we talked to Dr. Michele Lagioia, Medical Director of Humanitas.

What is monkeypox?

Monkeypox is a zoonotic viral disease (meaning that it can be transmitted from animals to humans) caused by the monkeypox virus belonging to the family Poxviridae (the same as smallpox).

It’s called "monkeypox" because the infection was first identified in monkeys in 1958, while the first case in humans dates back to 1970. It’s an endemic disease, meaning that it’s permanently present in the population, mostly in the tropical rainforest regions in central and western Africa.

The first outbreak of the disease outside of Africa was reported in 2003 in the United States and was linked to contact with pets infected by imported mammals. Between 2018 and 2021, 12 cases of monkeypox associated with travel outside of Africa were reported. In 2022, for the first time, many outbreaks not attributable either to travel or the import of mammals were reported in the European Union member states and further afield (including non-endemic countries). For this reason, the World Health Organization has declared monkeypox to be a Public Health Emergency of International Concern (PHEIC) and is working with health authorities in several countries to prevent the disease from spreading further.

What are the symptoms?

In humans, monkeypox often manifests as a combination of the following symptoms:

• Fever
• Headache
• Chills and shivering
• Fatigue
• Asthenia (general weakness)
• Swollen lymph nodes
• Back ache
• Muscle pains

Usually, a rash appears one to three days after the onset of a fever, often developing into blisters, pustules, and scabs. In the current epidemic, several European Union/European Economic Area countries have reported certain differences in the clinical manifestation of the disease to the European Center for Disease Prevention and Control (ECDC), compared with descriptions in medical literature.

In particular, patients have complained of milder symptoms appearing prior to the rash, such as fever, drowsiness, myalgia and headache. Skin lesions, which are sometimes early and precede other general symptoms, occur in 95% of patients, but may also appear as only a few and/or limited rashes in the genital or perianal area.

The anogenital areas, trunk, arms and legs as well as the face, palms of the hands and soles of the feet, are those most frequently affected. In 5% of cases, lesions may appear around and inside the mouth and throat.

If you develop any of these symptoms, you should isolate yourself and immediately consult your family doctor for instructions. The diagnosis of monkeypox is carried out clinically and also uses laboratory testing, including nucleic acid amplification tests (better known as PCR tests), generic tests for the orthopoxvirus (the viral genus called OPXV for short), and/or specific tests for the monkeypox virus carried out on DNA extracted from biological samples.

Monkeypox: how is it transmitted?

Animal-to-human infection occurs through physical contact with infected animals, including rodents and primates. However, person-to-person transmission can occur through close contact with someone with a monkeypox rash. Close contact includes skin-to-skin, mouth-to-mouth, or mouth-to-skin contact, and includes sexual contact. Transmission can also occur through contact with contaminated objects, such as clothing, towels, sheets, electronic devices or common surfaces. It can also be transmitted during pregnancy from mother to fetus or after delivery through skin-to-skin contact.

It's still not entirely clear for how long people can have monkeypox, but it's generally thought to start with the earlier signs of discomfort and malaise, and end once the scabs have fallen off, revealing a new layer of skin underneath. In the absence of any early symptoms, it can be considered to have started the day before the rash appears.

In the current outbreak, there is a predominance of cases among men who have sex with men (MSM), which suggests, also due to the nature of the lesions present in some cases, that the transmission occurred sexually. However, it is important to note that the risk of infection is not limited to people who are sexually active or to men who have sex with men: anyone who has close contact with an infected person is at risk of infection.

The use of condoms during sexual intercourse remains essential for the prevention of sexually transmitted diseases. However, this precaution is not enough in itself to prevent the risk of contracting the monkeypox virus, as infection can occur from any type of close contact.

How is monkeypox treated?

Monkeypox symptoms tend to resolve on their own in two to four weeks, without the need for treatment. However, if necessary, analgesics and antipyretics can be prescribed for the patient.

In some cases, an infection may lead to major complications requiring hospitalization and may even be fatal. In particular, infants, children and people with compromised immune systems may be at higher risk.

In the event of infection, the patient should be isolated from those living with them and should use, when possible, a personal bathroom, and not share clothes and objects. The patient should avoid contact with any pet, especially mammals, and wear a surgical mask when in the presence of other people. In general terms, it is important to keep well hydrated, eat healthily and get plenty of rest. Patients should not scratch their skin rashes and should make sure that hands are always clean, before and after touching their lesions.

Is there a vaccine against monkeypox?

The smallpox vaccine may provide cross-protection against the monkeypox virus. However, vaccination of the entire population is not required or recommended at this time.

In its August 5 circular, the Italian Ministry of Health provided indications for vaccination: given the current scenario and the limited availability of vaccines, pre-exposure prophylaxis (PrEP) is initially being offered to categories considered to be high risk:

> Laboratory personnel with possible direct exposure to the orthopoxvirus.

> Gay, transgender and bisexual people as well as men who have sex with men (MSM) with specific risk criteria reported in the circular.

> The vaccine available at this time is MVA-BN (Modified vaccinia Ankara, manufactured by Bavarian Nordic) and is distributed in Europe under the trade name IMVANEX. In the United States it is sold under the trade name JYNNEOS, and in Canada as IMVAMUNE.

> The vaccine is indicated for the prevention of smallpox and monkeypox in persons over 18 years of age who are at high risk of infection.

> The first vaccination (for those not previously vaccinated against either the smallpox virus or MVA-BN) consists of two doses to be given at least four weeks (28 days) apart.

> The booster vaccination is offered as a single jab for those who have previously received at least one dose of smallpox or MVA-BN vaccine in the past, or who completed the two-dose MVA-BN vaccination scheme over two years ago.

What to do if you have come into close contact with someone who has monkeypox

Isolating confirmed cases remains fundamental to containing the infection.

If you have come into contact with a confirmed case, you should:

> Check for the development of symptoms for 21 days after you were last exposed. Take your temperature twice a day and look out for monkeypox-related symptoms (e.g., headache, backache, swollen glands) or any unusual rashes.

> Refrain from sexual activity for 21 days after you were last exposed or until the possibility of infection has been ruled out.

> Avoid contact with other people until the risk of having contracted the disease has been excluded.

> Avoid close direct contact with animals (including pets) for 21 days after you were last exposed.

> Practice careful hand and respiratory hygiene.

> Avoid donating blood, cells, tissues, organs, breast milk, or sperm while the contagion period lasts.

> If you develop symptoms, isolate yourself and inform your family doctor immediately.

> Asymptomatic close contacts who are adequately managing their health can continue with their daily activities. In fact, unless expressly indicated by the local health authorities, there is no quarantine regime.