Eczema Vaccinatum (smallpox vaccine)



  • Eczema vaccinatum (EV) pathophysiology involves autoinoculation from the host vaccination site or close contact with implantation in the eczema site or healed lesion.
    • EV is relevant for ACAM 2000 as a live attenuated vaccine. This vaccine is contraindicated due to the high risk of EV in those with a current or prior history of atopic dermatitis, active exfoliative skin conditions or immunosuppression.
      • Jynneos (modified replication-deficient vaccinia Ankara) does not have a contra-indication for those with atopic dermatitis or eczema.
    • Work in the murine model suggests that NK cells are present in lower numbers; inhibition of IL-17 allowed the development of severe skin lesions[6].
    • The source in half of the cases in the 1960s was a household contact.
    • It can be either localized or systemic spread of the vaccinia virus.
      • Rash [Fig] typically occurs with fever and regional lymphadenopathy.
        • More photos and links are available on the CDC site.
      • EV is most severe when receiving immunization the first time, unimmunized close contacts and young children.
      • It can be fatal.
    • The most common sites are the face and flexor surfaces.
      • Lesions resemble vaccination sites but confluent + systemic illness +/- bacterial superinfection.
  • Ddx: smallpox, generalized vaccinia (no eczema), chickenpox, herpes viruses, Kaposi varicelliform eruption (due to HSV, enteroviruses in those with preexisting dermatosis), erythema multiforme.


  • DX: multiple vaccinia skin lesions outside vaccination site + exposure to vaccinia + current eczema or hx of eczema.
  • Eczema vaccinatum appears like the vaccination site but confluent and with systemic illness.


Eczema Diagnosis

  • Eczema and atopic dermatitis are interchangeable terms.
  • Relevance: most common contraindication to smallpox vaccination.
    • The risk applies to vaccine candidates AND any household contacts with active or prior eczema history.
    • Eczema pathophysiology: T cell immune defect + atopy with high IgE (85%).
  • Prevalence: 6-22% of the general population has eczema or prior hx; many more are misdiagnosed.
  • Eczema diagnosis in this context is clinical (history and exam) rather than lab-based. Skin biopsies are rarely pursued. High IgE levels or eosinophilia may be seen.
  1. Pruritis (dominant symptom)
  2. Dermatitis - flexor surfaces
  3. Dermatitis is chronic or recurrent
  4. Family hx atopy
  5. Onset by age 7
  • Skin changes:
    • Children: pruritic, red patches + scaling; face, scalp, extremities, trunk may be involved.
    • Adults: lichenification of flexor surfaces.
  • Recommended screening test questions (ACIP recommendation):
    • Have you or a family member
      • Ever had eczema/atopic dermatitis dx?
      • An itchy, red, scaly rash lasting over 2 weeks?


Also, see the CDC site for medical management of adverse reactions to vaccinia vaccination.

  • Contact Emergency Operations Center/CDC: T 770-448-7100 for consultation.
    • [Health care providers at military medical facilities (or civilian providers treating a U.S. Department of Defense healthcare beneficiary) should call the Defense Health Agency’s 24/7 Immunization Healthcare Support Center at 877-GETVACC (877-438-8222), and select option #1].
  • Vaccinia immune globulin (VIG): licensed by the FDA for treatment complications of vaccinia immunization.
    • EV is a VIG CDC-cleared indication for urgent use. Early treatment may be life-saving.
    • Dose: 0.6-1.0 mL/kg IM = 40ml IM
      • Severe/extensive lesions: up to 5-10 mL/kg in divided doses over several days have been used.
      • Currently only available as IM. Intravenous preparation may be available in the future.
  • Antivirals: see smallpox module.
    • Tecovirimat is FDA-approved for the treatment of smallpox.
    • Cidofovir: effective against smallpox in vitro.
      • Note: a severe case of contact eczema vaccinatum was reported in 2008. The child was treated with vaccinia IVIG, cidofovir, ST-246 [oral, experimental anti-pox compound], and skin grafts[7].
  • Bacterial superinfections: common and should be treated to cover anticipated pathogens such as streptococci, staphylococci or Gram-negatives.
    • Septic shock may complicate. Usual supportive care is recommended.


  • Eczema is the most common contraindication to the vaccine, and EV was the most common cause of vaccine mortality in the 1960s.
  • The best prevention of EV: careful history to assess for current or prior hx of eczema/atopic dermatitis.
  • VIG is brutal due to large IM volume; IV form is in production
  • GREATEST RISKS: age < 1yr, active eczema, primary vaccination.

Basis for recommendation

  1. Torres T, Ferreira EO, Gonçalo M, et al. Update on Atopic Dermatitis. Acta Med Port. 2019;32(9):606-613.  [PMID:31493365]

    Comment: Given the rising incidence, it is instructive to be fully up to date on diagnosing atopic dermatitis/eczema if administering the smallpox vaccine.

  2. CDC. Smallpox vaccines. (accessed 5/16/24)

    Comment: Helpful images and directions regarding immunization with vaccinia (currently ACAM2000 or Jynneos) regarding indications, exclusions, diagnosis of vaccine complications and management of adverse reactions.

  3. CDC. Smallpox Vaccination and Adverse Reactions. Guidance for Clinicians. MMWR 2/21/2003;


    Although Dryvax is no longer used, these recommendations remain listed in 2024 by the CDC as relevant for existing vaccines, ACAM2000.


  1. von Sonnenburg F, Perona P, Darsow U, et al. Safety and immunogenicity of modified vaccinia Ankara as a smallpox vaccine in people with atopic dermatitis. Vaccine. 2014;32(43):5696-702.  [PMID:25149431]

    Comment: This investigational vaccine did not appear to cause EV when administered to patients (n = 45) with allergic rhinitis or atopic dermatitis. The MVA is not thought to replicate significantly within the skin.

  2. Said MA, Haile C, Palabindala V, et al. Transmission of vaccinia virus, possibly through sexual contact, to a woman at high risk for adverse complications. Mil Med. 2013;178(12):e1375-8.  [PMID:24306023]

    Comment: Report of EV in a non-vaccinee who had atopic dermatitis and likely acquired from a sexual encounter with a recently immunized military person.

  3. Kawakami Y, Tomimori Y, Yumoto K, et al. Inhibition of NK cell activity by IL-17 allows vaccinia virus to induce severe skin lesions in a mouse model of eczema vaccinatum. J Exp Med. 2009;206(6):1219-25.  [PMID:19468065]

    Comment: In this murine model, blocking IL-17 appeared to replicate severe skin lesions, which these authors say potentially implicates a role for NK cells in pathogenesis in humans with atopy, etc.

  4. Vora S, Damon I, Fulginiti V, et al. Severe eczema vaccinatum in a household contact of a smallpox vaccinee. Clin Infect Dis. 2008;46(10):1555-61.  [PMID:18419490]

    Comment: A severe case of eczema vaccinatum in a child of vaccinated Iraq soldier on leave after smallpox vaccination. The child had eczema and was critically but survived with vaccinia IG, cidofovir, ST-246 and skin grafts.
    Rating: Important

  5. Reif DM, McKinney BA, Motsinger AA, et al. Genetic basis for adverse events after smallpox vaccination. J Infect Dis. 2008;198(1):16-22.  [PMID:18454680]

    Comment: Genotyping of patients with severe reactions to smallpox vaccination showed single nucleotide polymorphisms in the interferon regulatory factor-1 gene in those with severe reactions.
    Rating: Important

  6. Greenberg RN, Kennedy JS. ACAM2000: a newly licensed cell culture-based live vaccinia smallpox vaccine. Expert Opin Investig Drugs. 2008;17(4):555-64.  [PMID:18363519]

    Comment: Review of ACAM 2000, which was FDA-approved as a suitable replacement for Dryvax in the event of bioterrorism in 2007.

  7. Centers for Disease Control and Prevention (CDC). Secondary and tertiary transfer of vaccinia virus among U.S. military personnel--United States and worldwide, 2002-2004. MMWR Morb Mortal Wkly Rep. 2004;53(5):103-5.  [PMID:14961003]

    Comment: Among 407,923, 30 reported cases of contact vaccinia were reported. Most were "bed partners" - 12 spouses and 8 adult friends. There were no transmissions to health care workers or patients. The rate with primary vaccinees was 7.4/100,000, and for secondary vaccines, it was 5.2/100,000 (this may be underreported, but the data may be better in the military population, and the paucity of children compared to prior experience is striking).

  8. Naleway AL, Belongia EA, Greenlee RT, et al. Eczematous skin disease and recall of past diagnoses: implications for smallpox vaccination. Ann Intern Med. 2003;139(1):1-7.  [PMID:12834312]

    Comment: The frequency of atopic dermatitis is 0.8%, and it involves 2.3% of households. History will miss 30-40%.

  9. Neff JM, Lane JM, Fulginiti VA, et al. Contact vaccinia--transmission of vaccinia from smallpox vaccination. JAMA. 2002;288(15):1901-5.  [PMID:12377090]

    Comment: Review of contact vaccinia, which is transmitting this virus to others. Risk is close contact, which is nearly always household contact, occasionally in hospitals. The frequency of vaccines from the 1960s was 20-60/mil. Disease in the recipient depends on the host. The most significant risks are vaccinia necrosum in persons w/T cells, cell defects & eczema. Vaccination in persons with eczema was a considerable risk. This accounted for most vaccine-associated deaths and most uses of VIG. The most significant risks were young age & primary immunization. The risk of EV is thought to be substantially increased due to an increased rate of atopic dermatitis.
    Rating: Important

  10. Breman JG, Henderson DA. Diagnosis and management of smallpox. N Engl J Med. 2002;346(17):1300-8.  [PMID:11923491]

    Comment: Review of the disease. The last case was in 1977; the last in the U.S. was in 1949. SP vaccination stopped in the US in 1971, so few (< 30 years have been vaccinated). The vaccine is highly effective for at least 5-10 years. The disease is acquired by inhalation. Contagious primarily at the rash stage or about 3 weeks.

  11. Laughter D, Istvan JA, Tofte SJ, et al. The prevalence of atopic dermatitis in Oregon schoolchildren. J Am Acad Dermatol. 2000;43(4):649-55.  [PMID:11004621]

    Comment: This study showed a prevalence of atopic dermatitis to be 7-17%.

  12. Nettleton PF, Gilray JA, Reid HW, et al. Parapoxviruses are strongly inhibited in vitro by cidofovir. Antiviral Res. 2000;48(3):205-8.  [PMID:11164507]

    Comment: The MIC50 for cidofovir vs. vaccinia was 1.32 mcg/ml.

  13. Cooper KD, Kazmierowski JA, Wuepper KD, et al. Immunoregulation in atopic dermatitis: functional analysis of T-B cell interactions and the enumeration of Fc receptor-bearing T cells. J Invest Dermatol. 1983;80(3):139-45.  [PMID:6219166]

    Comment: Atopic dermatitis is associated with reduced CMI, defective antibody-dependent cellular cytotoxicity, reduced immunoregulatory T cells, elevated IgE, and a high incidence of IgE-mediated responses to skin tests to common inhaled antigens.

  14. Shirasawa K, Akai K, Kawaguchi Y, et al. Widespread eczema vaccinatum acquired by contacts. A report of an autopsy case. Acta Pathol Jpn. 1979;29(3):435-55.  [PMID:377910]

    Comment: This is a case report of lethal EV in a 4-month-old with "allergic dermatitis." Skin lesions showed vaccinia in the cytoplasm of cells at the stratum malpighii of the dermis, plus neutrophils and macrophages. The virus was also cultivated.


Eczema vaccinatum

Descriptive text is not available for this image

Typical rash of EZ.

Source: CDC

Last updated: May 16, 2024