Elias Mosialos: What we know about the monkeypox virus

In a social media post Elias Mosialosprofessor of health policy at Imperial College and the London School of Economics and Political Science (LSE), answers 14 questions about the monkeypox virus.

Below is the full text of Elias Mosialos’ message:

“On 7 May, the United Kingdom Health Insurance Agency (UKHSA) announced that a person who had recently visited Nigeria had contracted the monkeypox virus. Regarding the patient’s history, on April 29 he developed a rash, on May 4 he returned to the UK, where he was hospitalized. Two days later it was laboratory confirmed that the man had an infection caused by the smallpox virus. Contact tracing began on May 11 and the contacts have not shown any symptoms to date. In England, 7 out of 8 cases are not related to a recent trip to Africa, suggesting that the patients involved in these cases contracted the virus in England. In addition, these individuals had no contact with the patient who had traveled to Nigeria.

Currently, less than 100 cases have been registered worldwide (in some European countries, Canada, America, etc.). I believe that we will soon receive comprehensive information from the responsible health authorities (UKHSA, ECDC, CDC, WHO). But what do we know so far?

1. Is this a new virus?

No, it is a zoonotic disease endemic to many parts of Africa. Although it was first discovered in monkeys in 1958 (hence its name), it is also transmitted by rodents.

Portugal has already carried out the first analysis and mapping of the genetic material of the virus from a patient sample, which confirms that it is monkeypox virus sequenceassociated with a suspected outbreak in several countries in May 2022, a confirmed case in Portugal.

2. How is it transmitted?

From animals through close contact with humans, mainly through bites, scratches or contact with any animal body fluids. It is rare, but can also be passed between people who have very close contact. Transmission can occur by contact with body fluids and by airborne droplets, such as from fluid bubbles appearing on a patient’s skin, or if a person gets close enough to inhale airborne droplets. They usually can’t move more than 1 meter (according to the US Centers for Disease Control and Prevention). In addition, touching clothing, bedding, or towels used by monkeypox can also be dangerous.

Airborne (dust, inhalation) is one of the most common and fastest ways of transmitting infectious diseases. In this way, diseases caused by both viruses and bacteria can be transmitted. The inflammatory process of the mucous membranes of the upper respiratory tract contributes to the spread of pathogens. A large number of microbes are released with droplets of mucus when coughing, sneezing, talking, crying, screaming.

3. What symptoms does this virus cause?

The virus causes fever, body aches, swollen lymph nodes, and eventually “pox” – those painful, fluid-filled blisters on the face, arms, and legs. Monkeypox is usually mild and most people recover without treatment within 14 to 28 days. The infection can be divided into two periods:

A. The period of invasion (lasting up to 5 days) is characterized by fever, severe headache, swollen lymph nodes, pain in the back and muscles, severe weakness (failure). This swelling of the lymph nodes is a distinguishing feature of monkeypox compared to other diseases that may initially appear similar (such as chickenpox, measles).

B. Skin rash usually appears 1-3 days after the onset of fever. It tends to be more concentrated on the face and limbs than on the torso. The mucous membrane of the mouth is also affected (in 70% of cases), genitals (in 30%), eyes (conjunctiva in 20%), cornea. The rash develops successively from spots that gradually turn into vesicles (filled with a clear liquid), blisters (filled with a yellowish liquid) and crusts that dry up and fall off.

4. Do the blisters itch like chickenpox?

No, and there is one difference between these diseases: with monkeypox, blisters appear, and with chickenpox, the patient has itching. Only during the healing phase, when the skin regenerates, do monkeypox patients complain of itching.

5. How contagious is the detected strain?

The circulating virus is a mild strain (West African) and the mortality it can cause is 3-6% if there is no therapeutic intervention or vaccination. Monkeypox is less contagious than human pox and causes less serious illness.

6. But why are we seeing a reappearance?

People under the age of 40-50 (depending on the country) may be more susceptible to smallpox due to the cessation of smallpox vaccination campaigns around the world after the eradication of the disease.

7. How contagious is the virus compared to the coronavirus?

It is not as contagious as the coronavirus and has a different transmission curve. That is, it is much less contagious in the initial asymptomatic phase, but becomes more contagious when symptoms appear. It is truly contagious from the onset of symptoms, and the definition of “the course of the disease” is until the wounds heal and a new layer of skin forms. This can take quite a long time, maybe a few weeks.

8. Is there a vaccine?

Yes, there is a vaccine (the smallpox vaccine) that is about 85% effective in preventing serious illness, and it can also be given to people who are immunosuppressed. Early smallpox vaccination may result in milder illness.

9. So this virus can be treated?

Yes, with immediate and selective vaccination of infected contacts.

10. Are there treatments?

Clinical care for patients with monkeypox must be fully optimized to relieve symptoms, manage complications, and prevent long-term consequences. Patients should be provided with fluids and food to maintain proper nutritional status. It is very important to treat any secondary bacterial infections that may occur. An antiviral drug known as tecovirimat, developed for the treatment of smallpox, was licensed by the European Medicines Agency (EMA) for aphids in 2022, based on evidence from animal and human studies, but has not yet been widely adopted. If tecovirimat is used, it should ideally be monitored in clinical trials with prospective data collection.

11. When should I get vaccinated?

Vaccination is effective even after exposure to monkeypox virus. However, the sooner an infected person receives the vaccine, the better. The US Centers for Disease Control and Prevention (CDC) recommends that the vaccine be given within 4 days of exposure to prevent the onset of the disease. When given 4 to 14 days after infection, the vaccine reduces symptoms but usually cannot prevent the disease.

12. How can the risk of transmission be reduced?

Surveillance and the rapid detection of new cases, as we know, are vital to reducing the epidemic. Close contact with infected humans is the most important risk factor for monkeypox virus infection. Health care workers and family members are at greater risk of infection than the sick. Healthcare workers caring for patients with suspected or confirmed monkeypox virus infection or handling their samples should apply standard infection control measures. Ideally, people who have previously been vaccinated against smallpox should be selected to care for such patients.

13. But why worry?

The overall risk remains very low. But any disease that circulates among animals and can be transmitted to humans has the potential to cause a new pandemic if it mutates and becomes more contagious. Again, monkeypox has no specific treatment or vaccine. However, the smallpox vaccine confers immunity to monkeypox and can be used as a treatment if given immediately after infection.

14. Are we facing another pandemic?

There is no significant risk of a new pandemic from this virus. But the more people infected, the more likely it is that monkeypox will adapt to the human body. In addition, the more time the virus spends in the human body, the more time it has to evolve. In other words, it could evolve to spread faster among people.”