WHAT WE KNOW ABOUT THE LATEST MONKEY POX OUTBREAK

Medically Reviewed and Updated by Dr. Sony Sherpa (MBBS) - October 1, 2024

This article is continuously updated.

Monkeypox, now officially known as Mpox, is a viral disease caused by the Orthopoxvirus. The World Health Organization (WHO) renamed monkeypox to mpox in November 2022 to avoid stigma and discrimination.

Latest 2024 Update: Cases of Mpox Reported Outside Africa

The recent outbreak of mpox around the world has taken the scientific community by surprise. Although there were frequent outbreaks of mpox in the past, they were limited to specific areas. The recent outbreak, however, has involved multiple countries and seems to be spreading globally.

This has caused concern among the general public, more so because of various other outbreaks of different diseases happening at an increasing pace.

So, what is Mpox? Does it pose any life-threatening danger?

What Is Mpox?

Mpox is a viral infection. It is transmitted to humans from animals. The symptoms of mpox are similar to (but less severe than) those of another viral infection known as smallpox. Smallpox has been eradicated globally since 1980. (1)

However, following the eradication of smallpox, mpox emerged. Usually, mpox infections primarily occur in Central and West African rainforests. Lately, it has been seen even in urban areas as well. (2)

How Common Is Mpox?

Monkeypox in humans was first identified in 1970 in the Democratic Republic of the Congo in a 9-year-old boy. (3, 5) This region, in particular, had smallpox eliminated in 1968.

As of 2022, most cases were reported from the rainforest areas of rural regions of the Congo basin in the Democratic Republic of the Congo. However, recently, cases of mpox have increasingly been reported across Central and West Africa.

As of September 2024, the CDC has reported 99,618 confirmed mpox cases across 122 countries. The virus has spread far beyond its endemic regions in Central and West Africa, becoming a global concern. The outbreak in non-endemic countries has highlighted how easily the virus can spread through close physical contact, particularly in social and healthcare settings. Despite extensive efforts to control the spread, new cases continue to emerge in various parts of the world.

Can Mpox Be Fatal?

Mpox can indeed be fatal, with varying mortality rates depending on the virus strain. There are two primary strains of the virus: the West African clade, which has a lower fatality rate of around 1%, and the more virulent Central African clade, with a higher fatality rate of up to 10%. As of mid-2024, there have been 220 confirmed deaths from mpox globally. Although the overall fatality rate remains low, the virus poses a significant threat, particularly to vulnerable populations such as immunocompromised individuals, pregnant women, and young children.

Several complications can come along with mpox. Some of them are (2,5)

• Secondary infections
• Bronchopneumonia
• Sepsis
• Encephalitis, which is an infection of brain tissue
• Infection of the cornea, potentially leading to loss of vision.

What Are the Causes of Mpox?

Mpox is caused by the monkeypox virus. As mentioned above, the virus has two distinct family lines or clades. They are (3)

• Central African (Congo Basin) clade (identified as clade I; subtypes include Ia and Ib)
• West African clade (clade II; subtypes include IIa and IIb)

The Congo Basin clade is believed to be the more transmissible and severe of the two. (3)

Mpox is transmitted to humans from animals. (4) Some of the animals which are susceptible to mpox are (5)

• Rope squirrels
• Tree squirrels
• Gambian pouched rats
• Dormice
• Non-human primates and other species

However, more evidence is still required to pinpoint the exact reservoir of the virus.

What Are the Signs and Symptoms of Mpox?

Mpox is usually a self-limiting disease with symptoms lasting from 2 to 4 weeks. Severe cases are more commonly seen among children. Various factors, such as the extent of virus exposure, the patient’s health status, and the nature of complications, can significantly impact the outcome. (2, 3, 4, 5)

The incubation period (interval from infection to onset of symptoms) of mpox is usually from 6 to 13 days but can range from 5 to 21 days. (2, 3, 4, 5)

On the first five days of infection, you are more likely to suffer from (5)

• Fever
• Intense headache
• Lymphadenopathy (swelling of the lymph nodes)
• Back pain
• Myalgia (muscle aches)
• Lack of energy.
• Skin manifestations in the form of rash can be seen all over the body

Lymphadenopathy, or swollen lymph nodes, is a distinctive feature of mpox compared to other diseases that may initially appear similar, like chickenpox, measles, and smallpox. (3, 5)

The skin eruption usually begins within 1-3 days of the appearance of fever. The rash tends to be more concentrated on the face and extremities rather than on the trunk. In the majority of cases, the face is mostly affected, followed by the palms and soles. Other areas include oral mucous membranes, genitalia, and conjunctivae, which is the white portion of your eye. (2, 3, 5)

The rashes can be of varying shapes and sizes and thus can be confused with other diseases with a similar presentation, such as chickenpox. (5)

What Does Mpox Look Like?

Mpox symptoms can vary, with some individuals displaying only mild symptoms or none at all. The rash associated with mpox progresses through distinct stages: from flat spots to raised bumps, then to fluid-filled blisters, and finally to scabs. There are typically four mpox rash stages - macular, papular, vesicular, to pustular. This progression usually lasts between 2 to 4 weeks.

What To Do If You Suspect You Have An Mpox Infection?

If you suspect that you had close contact with someone diagnosed with mpox, you need to monitor yourself for the clinical signs and symptoms of the infection for at least 21 days after your exposure. Limit your contact with other people as much as possible. If there is any contact with others after the exposure, inform them that you have been exposed to mpox. (15)

While monitoring yourself, if you develop the characteristic symptoms of mpox, such as rash, fever, and lymphadenopathy, contact your healthcare provider immediately and ask for support regarding further testing and care. Isolate yourself till you get the test reports. Additionally, you need to clean your hands regularly.

If your test comes out to be positive, isolation is required, and your healthcare provider will advise you regarding isolation at the healthcare center or at home. They would also advise you on the care required.

During your isolation, you need to follow certain instructions, such as:

• Using a separate bathroom or cleaning it after use.
• Clean the surfaces you frequently touch with soap and water or disinfectant.
• Do not share towels, utensils, or any other things that you touch as much as possible.
• Do laundry on your own.
• Isolate in a well-ventilated room.
• Encourage other household members to wash their hands frequently.
• Use a medical mask when you are in close contact with others. Also, encourage others to use masks. Try to maintain a physical distance of at least 1 meter.

Differences Between Chickenpox, Smallpox, and Mpox

Chickenpox

• Cause: Varicella-zoster virus.
• Symptoms: Starts with fever and fatigue, followed by an itchy rash that turns from red spots to fluid-filled blisters, then crusts over.
• Transmission: Spread through coughs, sneezes, or contact with blister fluid.
• Complications: Usually mild in children but can be severe in adults and those with weakened immune systems.

Smallpox

• Cause: Variola virus.
• Symptoms: Begins with high fever and fatigue, followed by a rash that starts on the face and extremities, progressing to pustules and scabs.
• Transmission: Spread through direct contact or respiratory droplets.
• Complications: Severe and often deadly; eradicated through vaccination.

Mpox

• Cause: Orthopoxvirus.
• Symptoms: Similar to smallpox but often milder, starting with fever and swollen lymph nodes, followed by a rash that starts on the face and spreads.
• Transmission: Spread through contact with infected individuals or animals and sometimes respiratory droplets.
• Complications: Generally less severe than smallpox but can vary; recent strains may be more virulent.

Understanding these differences helps in diagnosing and managing the disease more effectively.

How Does Mpox Spread?

Mpox has been found to spread from animals to humans. This type of transmission is known as zoonotic transmission. Zoonotic transmission can occur from direct contact with the blood, bodily fluids, and skin lesions of infected animals. (4, 5)

Similarly, eating inadequately cooked meat and other animal products of infected animals is also a possible risk factor. (4, 5)

After a human is infected, he can transmit it to other humans. Human-to-human transmission can happen due to: (1, 2, 3, 4, 5)

• Close contact with respiratory secretions and droplets of an infected person
• Direct contact with the skin lesions of an infected person
• Direct contact with recently contaminated objects.
• Transmission can also occur via the placenta from the mother to the fetus or on close contact during and after birth.

According to the WHO, the risk of transmission from physical contact and sexual contact still requires more research, which is underway. (5)

How Can Mpox Transmission Be Prevented?

The transmission of mpox can be prevented through the following methods: (3, 5)

• Avoiding contact with animals that could carry the virus, especially in the endemic regions
• Avoiding contact with any materials, such as bedding, that have been in contact with a sick animal or person
• Isolating infected patients from others who could be at risk for infection.
• Practice good hand hygiene after contact with infected animals or humans. For example, washing your hands with soap and water or using an alcohol-based hand sanitizer.
• Using personal protective equipment (PPE) when caring for patients.
• Avoiding food containing animal parts from the endemic regions.
• Introducing stricter regulations on animal trade and handling of wild animals.

How Is Mpox Diagnosed?

Mpox is diagnosed both clinically and with the help of lab tests.

Clinically, mpox can resemble other rash-causing illnesses, such as chickenpox, measles, bacterial skin infections, scabies, syphilis, and medication-associated allergies. Mpox, however, presents with lymphadenopathy during the early days of infection. This can help differentiate it from other diseases of similar nature. (3, 5)

The confirmation of mpox, on the other hand, is done by various laboratory tests. The WHO has suggested health workers gather a sample and send it for appropriate testing. (5)

Polymerase Chain reaction or PCR is one such reliable test. PCR testing allows for the identification of the mpox virus in the sample. The sample is usually taken from lesions rather than blood, as the first one is more accurate. (3, 5)

One thing to consider is false-positive results, particularly in elder people who were vaccinated with the smallpox vaccine and health workers, especially lab personnel who have received some form of vaccination. (3, 5)

According to the WHO, for correct interpretation of results, the sample along with the following patient information must be clearly provided: (5)

• Date of onset of fever
• Date of onset of rash
• Date of specimen collection
• Current status of the individual (stage of rash)
• Age of the patient

It is, therefore, best to seek medical attention if you have any suspicious rash.

How Is Mpox Treated?

According to the Centers for Disease Control and Prevention (CDC), as of now, there is no proven treatment for mpox. (3)

Clinical care for mpox is being done symptomatically and can vastly differ from one person to another.

Doctors and healthcare providers are working to alleviate symptoms, manage complications and prevent long-term sequelae. (3, 5)

The CDC has also approved the use of the smallpox vaccine, vaccinia immunoglobulin, and antivirals to treat the monkeypox virus. (3)

An antiviral agent known as tecovirimat that was developed for smallpox was licensed by the European Medical Association (EMA) for monkeypox in 2022 for use within the European Union only. (5, 7)

Can Vaccines Prevent Mpox?

While smallpox vaccination has been shown to be effective in preventing mpox, its use for this purpose is currently under evaluation by the CDC and ACIP. As a result, laboratory and military personnel working with mpox are being recommended to receive a smallpox vaccine as a precautionary measure.

Current Vaccines for Mpox

1. JYNNEOS (also known as Imvamune or Imvanex)
   • Usage: Licensed for the prevention of mpox and smallpox.
   • Dosing: Administered as a two-dose series, with the second dose given four weeks after the first.
   • Latest Updates: JYNNEOS is currently the primary vaccine used to control mpox outbreaks. Due to its proven effectiveness against mpox and minimal side effects, it is the preferred option.
2. ACAM2000
   • Usage: An older smallpox vaccine that may offer protection against mpox.
   • Dosing: Administered as a single dose.
   • Latest Updates: Less commonly used due to its higher risk of side effects compared to JYNNEOS.

Side Effects of Mpox Vaccines

• JYNNEOS: Generally well-tolerated. Common side effects include mild fever, pain at the injection site, and fatigue. Rarely, severe allergic reactions may occur.
• ACAM2000: Can cause more severe side effects, including fever, rash, and in some cases, complications like myocarditis or pericarditis. It is generally used only when JYNNEOS is not available or suitable.

Timeline of Developments on Mpox

Mpox is not a new disease; there have been multiple outbreaks in the past. However, recently the outbreak has involved multiple countries, and the disease has spread globally.

Ongoing Updates (2024)

Surveillance and research efforts are ongoing to monitor the new strain’s impact. Current focus areas include evaluating vaccine efficacy, exploring new treatment options, and improving preventive measures.

August 2024

• The first confirmed case of a more dangerous strain of mpox (Clade 1b) outside Africa was reported in Sweden. This marks a significant development in the ongoing mpox outbreak, as this clade is typically associated with more severe symptoms and higher transmission rates.
• Thailand confirmed its recent mpox case was linked to the Clade 1b strain, making it the second confirmed case of this strain outside Africa
• On August 14th, the WHO declared the mpox outbreak a Public Health Emergency of International Concern (the second in two years). This declaration was made in response to the rapid spread of the newly identified, more dangerous strain of mpox across several countries outside Africa. The declaration aims to coordinate international resources and enhance efforts to control the outbreak.

December 2023

A new variant of mpox, identified as more virulent, was reported outside Africa, prompting enhanced surveillance and response efforts from international health authorities.

August 2023

• The WHO updated its guidelines on mpox management and prevention, highlighting the continued global response to the outbreak and the importance of vaccination and containment strategies.
• On the 23rd of July, WHO declared the monkeypox outbreak a Public Health Emergency of International Concern. (14)
• Outside the endemic region, the first death due to monkeypox infection was reported in Brazil, followed by Spain.
• The following vaccines were discussed for the prevention of monkeypox infection: ACAM2000, Jynneos, APSV: Aventis Pasteur smallpox vaccine, IMVANEX, Imvamune, LC16m8, and smallpox vaccine (dried and frozen liquid formulation). However, further study is required for the clinical safety and characterization of the immunity. (13)
• For contacts of cases, post-exposure prophylaxis (PEP) with the vaccine is advised, ideally within four days of the first exposure (and up to 14 days in the absence of symptoms). (14)
• Pre-exposure vaccination is recommended for health workers at high risk of exposure, laboratory personnel working with orthopoxviruses, clinical laboratory personnel performing diagnostic testing for monkeypox, outbreak response team members, and other individuals involved who may be at risk in this outbreak, such as people with multiple sex partners. (14)
• On 28th June, WHO published guidance to provide public health advice for gatherings during the current monkeypox outbreak. (14)

June 2022

• On June 25, WHO declared that the monkeypox virus outbreak was not a global health emergency. (12)
• The CDC updated and expanded its case definition to encourage testing for monkeypox infection to take early steps to protect contacts. It also alerted healthcare providers about the issue of disease courses differing from the past outbreaks in central and western Africa. Also, community cases increased with infection seen among those without international travel. (11)
• Scientific development of a CORE protocol for the universal standardized treatment of monkeypox was planned, and a structure was developed for conducting the study. A randomized, placebo-controlled trial for the drug Tecovirimat was planned. The study population would be outpatients and inpatients; children, pregnant women, and immunosuppressed patients. The time to resolution of lesions was considered the endpoint variable. The study design was conducted under the WHO.(13)

May 2022

• Monkeypox infection was identified in a British resident who had been to Nigeria, which is considered an endemic region for the disease. He developed a rash on the 29th of April, arrived in the United Kingdom on May 4th, and was diagnosed with monkeypox on May 6th. (1,2)
• On the 12th of May, further cases were identified in the UK in those who had not been to the endemic region. (3)
• Further cases of monkeypox infection were identified on May 18th in Portugal, Spain, the United States, and Canada. (4,5)
• A genomic analysis of the virus in Portugal revealed that the virus is related to the monkeypox cases in Nigeria in 2018 and 2019. (6)
• The United States ordered 13 million smallpox vaccines from Bavarian Nordic. (7)
• On May 20, Belgium became the first country to impose mandatory isolation for people infected with monkeypox for 21 days. The United Kingdom advised people to self-isolate if identified, but it was not mandatory. (9)
• Some countries, such as Canada, Montreal, and Quebec, have started vaccinating people with a high risk of exposure. (10)
• CDC issued a health advisory on May 20, asking clinicians to be vigilant toward the characteristic rash of monkeypox. (11)
• For the prevention of monkeypox, restrictions were placed on the animal trade, and it was advised that animals with potential infection be isolated, and those with contact be quarantined and observed for symptoms of monkeypox for 30 days.

Frequently Asked Questions

Can Mpox be Mistaken for Mosquito Bites?

Yes, the initial rash of mpox can sometimes be confused with mosquito bites. However, mpox lesions typically evolve from flat spots to raised bumps and then to fluid-filled blisters before crusting over. Unlike mosquito bites, which are usually localized and do not progress through multiple stages, mpox lesions tend to appear in clusters and may spread across different parts of the body.

Is Mpox Contagious?

Yes, mpox is contagious. It spreads through direct contact with infected individuals, animals, or contaminated materials. Transmission can occur via respiratory droplets, bodily fluids, or contact with lesions. Mpox is less contagious than some other viral infections, but close contact is still a significant risk factor.

What are the First Signs of Mpox?

The first signs of mpox typically include:

• Fever
• Headache
• Muscle aches
• Fatigue
• Swollen lymph nodes

Takeaway

The mpox cases identified in 2022 and 2024 have been slightly worrisome. While the previous outbreaks involved some form of contact with the endemic areas, the latest outbreak has no direct links to travel to those areas.

Further investigations are underway to determine the likely source of infection. Active measures and surveillance programs have been called into play, and health professionals are being asked to report and investigate suspected cases.

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