Vaccine

Contraindications

Five groups of persons are ordinarily considered at special risk of smallpox vaccine complications: (9:9)

  1. Persons with eczema or other significant exfoliative skin conditions.
  2. Patients with leukemia, lymphoma, or generalized malignancy who are receiving therapy with alkylating, antimetobolites, radiation, or large doses of corticosteroids.
  3. Patients with HIV infection.
  4. Persons with hereditary immune deficiency disorders.
  5. Pregnancy in the recipient or a household contact.

Healthcare providers who have a contraindication to vaccination should not handle or administer the vaccine. (22:V6:43)

Pregnancy

Regarding pregnancy, smallpox vaccine should not be administered to pregnant women or people with pregnant household contacts for non-emergency indications. (22:V6:26) Pregnancy should also be avoided for at least 4 weeks after vaccination. (22:V6:26) Pregnancy is a contraindication because of the risk of fetal vaccinia, a very rare complication of smallpox vaccination. (22:V6:26) To further reduce the risk of inadvertently vaccinating a woman who is pregnant, at the time of pre-screening, women of child-bearing age should be educated about fetal vaccinia, and abstinence or contraception to reduce the risk of pregnancy before or within four weeks after vaccination. (22:V6:28)

Allergic Reactions

The vaccine is contraindicated for persons who have experienced a serious allergic reaction to a prior dose of smallpox vaccine, or to a smallpox vaccine component. By serious reaction, we mean anaphylaxis or symptoms of an anaphylaxis-like reaction, such as generalized urticaria, wheezing, or difficulty breathing. (22:V6:20) In addition to live vaccinia virus, the reconstituted Dryvax vaccine contains trace amounts of the antibiotics polymyxin B, streptomycin, tetracycline, and neomycin. It also contains phenol as a preservative. People with serious allergy to any of these products shold not be vaccinated. The newer cell culture vaccines do not contain antibiotics. No smallpox vaccine in the United States contains sulfa-type antibiotics or penicillin.

Immunosuppression

Contraindicated for people with significant immunosuppression, or who have an immunosuppressed household contact. Replication of vaccinia virus can be enhanced among people with immunodeficiency diseases and immunosuppression, and result in serious adverse reactions. (22:V6:22)

Significant immunosuppression can be caused by many diseases, including leukemia, lymphoma, generalized malignancy; solid organ or stem cell transplantation; and humoral or cellular immunity disorders, including HIV infection. Certain autoimmune diseases and/or treatment for autoimmune diseases may also be immunosuppressive. (22:V6:23)

Therapies that can cause immunosuppression include alkylating agents, antimetabolites, radiation, or high dose corticosteriod therapy. Prednisone doses of 2 milligrams per kilogram of body weight per day or higher or 20 milligrams per day or higher fo r14 days or more should be considered immunosuppressive. As with other live vaccines, those on high levels of these drugs should not be immunized for three months after their last dose. (22:V6:24)

Persons with HIV infection or AIDS are at increased risk of progressive vaccinia (vaccinia necrosum) following vaccinia vaccination. Therefore, vaccinia vaccine should not be administered to persons with HIV infection or AIDS. Before vaccination, potential vaccinees should be educated about the risk of severe vaccinial complications among persons with HIV infection or other immunosuppressive conditions; persons who think they may have one of these conditions should not be vaccinated.

The Advisory Committee on Immunization Practices (ACIP) does not recommend mandatory HIV testing prior to smallpox vaccination, but recommends that HIV testing should be readily available to all persons considering smallpox vaccination. HIV testing is recommended for persons who have any history of a risk factor for HIV infection and who are not sure of their HIV infection status. Because known risk factors cannot be identified for some persons with HIV infection, anyone who is concerned that they could have HIV infection also should be tested. HIV testing should be available in a confidential or, where permitted by law, anonymous setting with results communicated to the potential vaccinee before the planned date of vaccination. Persons with a positive test result should be told not to present to the vaccination site for immunization. Information about local testing options should be provided to all potential vaccinees, including sites where testing is performed at no cost. (22:V6:25)

Eczema

Those people with eczema or a past history of eczema should not be vaccinated, or those whose household contacts have a history of eczema because of the risk of inadvertent transmission.
People with other types of acute, chronic, or exfoliative skin conditions, such as psoriasis, contact dermatitis, burns, impetigo, or herpes zoster (shingles) might be at higher risk for inadvertent inoculation from the vaccine. People with exfoliative skin conditions, or whose household contacts has this condition, should not be vaccinated until the condition resolves or is under good control. (22:V6:30)

To assist providers in identifying persons that should defer smallpox (vaccinia) vaccination, the ACIP offers the following two screening questions: (22:V6:31)

  1. Have you, or a member of your household ever been diagnosed with eczema or atopic dermatitis – if you answered “yes,” you may NOT receive the smallpox (vaccinia) vaccine due to the risk that you or your household contact might develop a severe and potentially life-threatening illness called eczema vaccinatum;
  2. Eczema/atopic dermatitis usually is an itchy red, scaly rash that lasts more than 2 weeks and often comes and goes. If you or a member of your household have ever had a rash like this – you should NOT receive the smallpox (vaccinia) vaccine at this time unless you and a healthcare provider are sure that this rash is not atopic dermatitis or eczema.

In cases where the dermatological risk factor or diagnosis is uncertain, some organizations, such as the military or CDC, may elect to develop more precise screening tools. Theses secondary screening tools should weigh the individual’s risk of developing an adverse event with the requirement of occupational readiness through safe smallpox vaccination to ensure national security.

Age

People less than 18 years of age should not be vaccinated. Children less than 12 months of age should not be vaccinated. (22:V6:32) All vaccinated people should take precautions to prevent virus transmission to young children and other household contacts. (22:V6:32) Infants are at risk of post-vaccinial encephalitis if infected. (22:V6:32)

Other Contraindications

People with moderate or severe acute illnesses should defer vaccination. People acute or chronic skin conditions that cause breaks in the skin like, burns, impetigo, or contact dermatitis (until the condition is resolved) (22:V1:36)Breastfeeding in the vaccinee (due to close skin contact) (22:V1:36) In the event of an exposure to smallpox, there would be no contraindications to vaccination. In this situation, the benefit of vaccination would outweigh the risk of a complication from the vaccine. (22:V1:37)

For more information on smallpox vaccine, contraindications, and adverse events refer to the CDC’s pre-clinic screening packet. (Note: you need Microsoft PowerPoint in order to view this link.) (22:V6:36) The packet contains: a participant advice letter, a vaccine information sheet and a pre-clinic checklist. The vaccine information sheet includes information on the smallpox vaccine, immune system problems, skin conditions and pregnancy. 

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