Who is at Highest Risk for Suffering Complications from Smallpox and Monkeypox?

Updated August 13, 2022


Smallpox

The last known case of smallpox reportedly occurred in Somalia in 1977. In May 1980, smallpox was declared eradicated by the World Health Organization (WHO).1

When smallpox was common, persons who developed malignant (flat-type) smallpox, a rare form of smallpox that was more common among children, were at high-risk of complications. This form of smallpox was identified by skin lesions that developed  slowly, merged together, and became soft and flat. Most cases of flat-type smallpox were fatal due to toxemia,2  and 97 percent of individuals who developed this form of smallpox died.3 Persons who developed hemorrhagic smallpox, another form of the disease, were also at high-risk of complications and death. Hemorrhagic smallpox had prodromal symptoms that were usually more severe than the more common form of the disease, Variola Major, and was usually fatal by the fifth or sixth day after rash onset. Death usually occurred from toxemia that caused multi-system organ failure.4 Nearly all cases of hemorrhagic smallpox were fatal.5

An April 2018 published study examining the risk of smallpox reemergence concluded that individuals 40 years of age and older were more at risk of death from smallpox. While persons in this age range were more likely to have been previously vaccinated, higher rates of immunosuppression were prevalent in this population. Persons with immunosuppressive conditions are considered at higher risk of death from smallpox.6

Monkeypox

Individuals most at risk for complications from monkeypox are those who are immunocompromised or have other underlying medical conditions. Young children who are exposed to large amounts of the virus may also be at a greater risk of suffering complications from the illness.7

IMPORTANT NOTE: NVIC encourages you to become fully informed about smallpox and the smallpox vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself. This information is for educational purposes only and is not intended as medical advice.


References:

[1] National Organization for Rare Disorders. Smallpox. In: Rare Disease Database. 2009.

[2]  U.S. Centers for Disease Control and Prevention. Clinical Disease. In Smallpox. Dec. 5, 2016.

[3] Johns Hopkins Bloomberg School of Public Health Center for Health Security. Variola Virus (Smallpox). Feb. 26, 2014.

[4] U.S. Centers for Disease Control and Prevention. Clinical Disease. In Smallpox. Dec. 5, 2016.

[5] Johns Hopkins Bloomberg School of Public Health Center for Health Security. Variola Virus (Smallpox). Feb. 26, 2014.

[6] MacIntyre C, Costantino V. Chen X, et al. Influence of Population Immunosuppression and Past Vaccination on Smallpox Reemergence. Emerg Infect Dis. Apr. 2018;24(4):646-653.

[7] Sreenvas, S. Monkeypox: What to Know. WebMD June 8, 2022.

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