Mpox vs. Chickenpox

Mpox and chickenpox are two diseases often confused due to their shared symptom of skin rashes. However, these illnesses have vastly different origins, transmission patterns, clinical features, and prevention strategies. By dissecting their biological and epidemiological aspects, this article provides a detailed, research-driven comparison of mpox and chickenpox.

Origins of Mpox and Chickenpox

Mpox Associated with the Orthopoxvirus Family

Mpox, formerly called monkeypox, is caused by the mpox virus, a zoonotic pathogen belonging to the Orthopoxvirus genus. This genus also includes the variola virus, responsible for smallpox. Mpox was first identified in monkeys in 1958, with human cases emerging in the Democratic Republic of Congo in 1970. The disease has historically been limited to Central and West Africa but gained global attention during outbreaks in recent years.

Chickenpox Caused by the Varicella-Zoster Virus

Chickenpox, on the other hand, is caused by the varicella-zoster virus (VZV), part of the Herpesviridae family. Unlike mpox, it is not zoonotic and primarily infects humans. The varicella-zoster virus causes two distinct illnesses: chickenpox during initial infection and shingles upon reactivation later in life. This virus is highly contagious and has historically been a widespread childhood disease.

Transmission of Mpox and Chickenpox

Mpox Transmission

Mpox spreads through:

• Close Contact: Direct contact with lesions, bodily fluids, or respiratory droplets from infected individuals.
• Animal Reservoirs: Rodents and primates serve as natural reservoirs, making zoonotic transmission significant.
• Fomites: Contaminated materials like bedding can harbor the virus for extended periods.

Mpox is less contagious among humans than chickenpox, requiring prolonged or intimate contact for efficient transmission.

Chickenpox Transmission

Chickenpox spreads more efficiently, primarily via:

• Airborne Transmission: Respiratory droplets expelled by coughing or sneezing.
• Direct Contact: Exposure to the fluid from chickenpox blisters.
• Environmental Contamination: Surfaces contaminated with virus-laden particles can also be infectious.

Its high transmissibility often leads to rapid outbreaks, especially in unvaccinated communities.

Symptoms of Mpox and Chickenpox

Mpox Symptoms

Mpox typically presents in two stages:

1. Prodromal Stage: Fever, headache, muscle aches, and characteristic swollen lymph nodes. Swollen nodes are a hallmark feature that differentiates mpox from chickenpox.
2. Rash Stage: Lesions progress from flat macules to raised papules, pustules, and eventually scabs. These lesions are often larger and more painful than chickenpox blisters and tend to appear in clusters.

Chickenpox Symptoms

Chickenpox follows a simpler progression:

1. Initial Symptoms: Low-grade fever, fatigue, and loss of appetite.
2. Rash Development: An itchy rash appears, starting on the torso and spreading outward. The lesions exist at various stages (red spots, fluid-filled blisters, and scabs) simultaneously, a key identifying feature.

Fig 1. Comparison of clinical presentation of mpox and chickenpox¹

Complications of Mpox and Chickenpox

Mpox Complications

Mpox is generally more severe, especially in immunocompromised individuals or those with coexisting conditions. Complications can include:

• Secondary bacterial infections.
• Respiratory issues such as pneumonia.
• Neurological complications like encephalitis.
• Mortality rates range from 1% to 10%, depending on the viral strain and healthcare access.

Chickenpox Complications

Chickenpox is usually mild in children but can lead to severe outcomes in vulnerable populations, such as:

• Adults and pregnant women.
• Immunocompromised individuals.
• Complications include bacterial infections of the skin, pneumonia, and, in rare cases, encephalitis.
• The mortality rate is extremely low, especially in vaccinated populations.

Prevention of Mpox and Chickenpox

Mpox Prevention

Efforts to prevent mpox focus on containment and immunization:

• Vaccination: The smallpox vaccine offers partial protection, with newer vaccines like JYNNEOS providing more targeted prevention for high-risk groups.
• Public Health Measures: Avoiding contact with infected individuals or animals, maintaining hygiene, and isolating cases during outbreaks are critical.
• Global Challenges: Limited vaccine availability in endemic regions like Central Africa highlights the need for expanded access.

Chickenpox Prevention

Chickenpox prevention relies heavily on vaccination:

• Widespread Immunization: The varicella vaccine is a cornerstone of public health, dramatically reducing chickenpox cases worldwide.
• Herd Immunity: High vaccination coverage ensures population-wide protection.
• Efficacy: Vaccines not only prevent infection but also reduce the severity of breakthrough cases.

Epidemiology of Mpox and Chickenpox

Mpox Epidemiology

While traditionally endemic to Africa, mpox outbreaks have become global, with increasing cases reported in the United States, Europe, and Asia. Efforts to track and contain the virus have intensified, but challenges remain in surveillance and resource allocation.

Chickenpox Epidemiology

Chickenpox was once a universal childhood illness but has become rare in regions with widespread vaccination. Unvaccinated populations, however, remain at risk, particularly in developing countries or regions with vaccine hesitancy.

Key Insights on Mpox and Chickenpox

Mpox and chickenpox, despite their similar names and overlapping symptoms, represent distinct viral diseases with unique challenges for public health and research. Mpox, with its zoonotic origins and severe complications, underscores the importance of surveillance and strategic vaccination. Meanwhile, chickenpox highlights the success of global vaccination campaigns in controlling highly contagious diseases. As a leading CRO, Creative Biolabs specializes in providing comprehensive solutions for mpox drug discovery. With cutting-edge expertise in virology and immunology, we supports research into novel therapeutic targets, vaccine development, and diagnostic tools to better understand and combat viral diseases like mpox and chickenpox.

Resources