Smallpox & Monkeypox Disease & Vaccine Information

Find the Information You Need to Make an Informed Vaccine Decision
Updated September 10, 2022


Smallpox (right) Monkeypox (left) CDC PHIL

Smallpox/Monkeypox: The Disease


Smallpox is an illness caused by the variola virus, a virus belonging to the orthopoxvirus family of viruses.1 Symptoms of the disease include head and backache, anorexia, severe abdominal pain, vomiting, extreme exhaustion, malaise, chills, rash, and high fever. When the fever resolved, rash lesions would begin to develop and appear in the back of the mouth, behind the oral cavity (oropharynx), followed by the face, arms, legs, and then would have spread to the torso, palms and soles.2 When smallpox was circulating in the environment, there were several forms of the disease, with some more severe and life-threatening than others.3

Monkeypox is an infection caused by the monkeypox virus and like smallpox is also a member of the Orthopoxvirus family.4 Symptoms of monkeypox are similar to smallpox but are generally milder. Individuals infected with monkeypox usually present with headache, backache, fever, chills, muscle aches, extreme fatigue and exhaustion. Swelling of the lymph nodes also occurs, which is a symptom not present with smallpox infection.5 A rash, which usually appears on the face, begins within one to three days of fever, and spreads throughout the body.6 Monkeypox is rare and is generally found in Africa, although cases and outbreaks have occurred globally.7 Learn more about smallpox/monkeypox…

Smallpox/Monkeypox: The Vaccine

There are two smallpox vaccines approved by the U.S. Food and Drug Administration (FDA): ACAM 2000, a live smallpox (vaccinia) vaccine, and JYNNEOS, a live, non-replicating, smallpox and monkeypox vaccine. A third vaccine, Aventis Pasteur Smallpox Vaccine (APSV), is an unapproved vaccine that has been added to the Strategic National Stockpile (SNS).8 Learn more about smallpox/monkeypox vaccine…

Smallpox/Monkeypox Quick Facts

Smallpox/Monkeypox

  • Smallpox is an illness caused by the variola virus, belonging to the orthopoxvirus family. There are several forms of smallpox illness, including Variola Major, modified-type smallpox, hemorrhagic smallpox, malignant (flat-type) smallpox, and Variola Minor. Variola Major was the most common form of the illness when smallpox was circulating in the environment.9 Initial symptoms of smallpox illness included anorexia, vomiting, malaise, high fever, chills, headache, backache, severe abdominal pain, pharyngitis, and extreme exhaustion. A rash might have also been visible in light-skinned individuals. Rash lesions would begin after the fever resolved and appear in the back of the mouth, behind the oral cavity (oropharynx), followed by the face, arms, and legs, and would eventually spread to the torso, palms, and soles.10
  • Monkeypox, another orthopoxvirus, is similar in symptoms to smallpox but generally milder. With monkeypox, infected individuals develop swelling of the lymph nodes.11

Smallpox/Monkeypox Vaccine

  • There are two smallpox vaccines approved by the U.S. Food and Drug Administration (FDA). The ACAM 2000 vaccine is a live smallpox (vaccinia) vaccineapproved for use in persons considered at high risk for smallpox infection. The JYNNEOS vaccine is a live, non-replicating, smallpox and monkeypox vaccine and approved for use in adults 18 years of age and older who are considered to be at high-risk of smallpox or monkeypox.12
  • Serious adverse events reported following ACAM 2000 vaccination include encephalitis (brain inflammation), encephalomyelitis (inflammation of brain and spinal cord), encephalopathy (disease of brain causing alteration of brain function or structure), generalized vaccinia (systemic spread of the virus from the inoculation site), progressive vaccinia (vaccinia necrosum – death of bodily tissues), severe vaccinial skin infections, eczema vaccinatum, erythema multiforme major including Stevens-Johnson syndrome (severe and potentially life threatening skin and/or mucus membrane lesions), blindness, and fetal death in pregnant women. These complications have the potential to cause severe disability, permanent neurological deficits, and death.13 Serious adverse events reported during clinical trials for the JYNNEOS vaccine noted in the product insert include Crohn’s disease, sarcoidosis (inflammatory disease affecting organs), extraocular muscle paresis (weakening of eye muscles) and throat tightness.14 Continue reading quick facts…

Learn More About Smallpox/Monkeypox and Smallpox/Monkeypox Vaccine

NVIC encourages you to become fully informed about Smallpox/Monkeypox and the Smallpox/Monkeypox vaccine by reading all sections in the Table of Contents provided on this webpage. NVIC provides highly referenced information that allow the public to click through to the reference material used to compile this information, such as the manufacturer product information inserts maintained on the U.S. Food & Drug Administration's website and vaccine information statements issued by the U.S. Centers for Disease Control and Prevention. As you consider vaccination, we encourage the public to educate themselves on the disease and vaccine and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

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References:

[1] Babkin IV, Babkina IN. The origin of the variola virus. Viruses Mar. 2015;7(3):1100-12.

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

[3] Babkin IV, Babkina IN. The origin of the variola virus. Viruses Mar. 2015;7(3):1100-12.

[4] U.S Centers for Disease Control and Prevention. About Monkeypox. In: Monkeypox. Nov. 23, 2021.

[5] U.S Centers for Disease Control and Prevention. Signs and Symptoms. In: Monkeypox. July 16, 2021.

[6] U.S Centers for Disease Control and Prevention. Signs and Symptoms. In: Monkeypox. July 16, 2021.

[7] U.S. Centers for Disease Control and Prevention. About Monkeypox. In: Monkeypox. Nov. 23, 2021.

[8] U.S. Centers for Disease Control and Prevention. Vaccines. In: Smallpox. Dec. 2, 2019.

[9] U.S. Food and Drug Administration. Smallpox. Mar. 23, 2018.

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

[11] U.S Centers for Disease Control and Prevention. Signs and Symptoms. In: Monkeypox. July 16, 2021.

[12] U.S Food and Drug Administration. Vaccines Licensed for Use in the United States. Jan. 31, 2022.

[13] Emergent Product Development Gaithersburg, Inc. ACAM2000 – Package Insert. U.S Food and Drug Administration. Dec. 13, 2019.

[14] Bavarian Nordic A/S Package Insert – JYNNEOS. U.S. Food and Drug Administration. June 21, 2021.

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