How is monkeypox transmitted?

Monkeypox Transmission

Monkeypox is transmitted primarily through direct contact with infected animals or persons, including contact with infectious skin lesions, scabs, body fluids, and respiratory droplets during prolonged face-to-face interactions, as well as through contaminated fomites such as bedding and towels. 1, 2, 3

Primary Transmission Routes

Direct Contact Transmission

• Direct skin-to-skin contact with infectious lesions, scabs, or body fluids from infected persons or animals is the predominant mode of transmission 2, 4, 3
• Intimate contact during sexual activity, kissing, cuddling, or touching affected body parts facilitates person-to-person spread 2
• Contact with infected animals, particularly prairie dogs (as documented in the 2003 U.S. outbreak), serves as the zoonotic transmission pathway 1, 5

Respiratory Droplet Transmission

• Transmission occurs through respiratory droplets during prolonged face-to-face interactions, requiring extended close contact rather than casual exposure 6, 4
• This route is less efficient than direct contact transmission and requires sustained proximity 6

Fomite Transmission

• Contaminated objects including towels, bedding, clothing, and other materials that have contacted infectious lesions can transmit the virus 2, 3
• This indirect contact route represents a significant transmission pathway in household and healthcare settings 3

Key Transmission Characteristics

Infectious Period and Risk Factors

• Patients are most infectious when skin lesions are present, with crusted lesions representing active viral shedding 1
• The greatest transmission risk occurs among household members and close contacts with prolonged exposure 6, 4
• Vulnerable populations including young children, pregnant women, and immunocompromised individuals face higher risk of severe disease following transmission 6

Comparison to Other Orthopoxviruses

• While monkeypox shares transmission characteristics with smallpox (both orthopoxviruses), it has lower transmissibility than diseases like measles, pertussis, and influenza 7
• Unlike smallpox, which had significant airborne transmission in healthcare settings, monkeypox primarily spreads through direct contact routes 7

Prevention Strategies

Personal Protective Measures

• Wearing surgical masks during close contact with infected individuals reduces respiratory droplet transmission 6
• Adequately covering skin lesions prevents direct contact transmission 6
• Avoiding handling of wild animals, particularly rodents and primates in endemic areas, prevents zoonotic acquisition 6, 4

Hand Hygiene

• Hand hygiene after any potential exposure is the single most important preventive measure, consistent with standard precautions for contact transmission 1
• This applies to both animal and human contact scenarios 1

Environmental Controls

• Proper handling and disinfection of contaminated fomites including bedding, towels, and clothing is essential 3
• Isolation of infected patients prevents further transmission to household and healthcare contacts 7

Clinical Pitfalls

A critical caveat: The 2022 global outbreak demonstrated that monkeypox can spread efficiently through intimate contact networks, challenging earlier assumptions that it primarily remained a zoonotic disease with limited human-to-human transmission 2, 5. Healthcare providers must maintain high clinical suspicion in patients presenting with characteristic rash and relevant exposure history, even in non-endemic regions 5.