Who is at highest risk for complications from Smallpox and Monkeypox (Mpox) vaccine?

There is a gap in medical knowledge in terms of doctors being able to predict who will have an adverse reaction to smallpox vaccination, and who will not.

Smallpox (Vaccinia) Vaccine, Live (ACAM 2000)

Individuals considered at a higher risk for complications from ACAM 2000 include persons with: 

• Cardiac disease;
• Eye disease, including those receiving treatment with corticosteroids; and
• History of skin disorders which include the presence of eczema or additional skin conditions.

Additionally, pregnant women and infants under one year of age are considered at a higher risk for complications.

Persons with a history of severe allergic reaction to a prior smallpox vaccine are also at a higher risk of complications. This includes people with a history of allergic reaction to polymyxin B and Neomycin, two ingredients contained within the vaccine. 

Smallpox and Monkeypox (Mpox) Vaccine, Live, Non-Replicating (JYNNEOS)

Persons who have previously experienced a severe allergic reaction to JYNNEOS vaccine may be at a higher risk of experiencing an additional serious reaction to a second dose. 

IMPORTANT NOTE: NVIC encourages you to become fully informed about smallpox/monkeypox (Mpox) and the smallpox/monkeypox (Mpox) 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.

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