Supplemental Recommendations to the ACIP Smallpox Vaccination Guidelines

The Advisory Committee on Immunization Practices (ACIP) released a report on February 26, 2003 that supplements its 2001 statement regarding guidelines for the government's smallpox vaccination program.

The following summary provides information taken directly from that report.

The complete text of the ACIP supplemental recommendations is available at the CDC bioterrorism website.

Excerpts from the Advisory Committee on Immunizations Practices (ACIP) Supplemental Recommendations - February 26, 2003

What is the Level of Disease Risk and Threat?

  • Information provided to ACIP indicated that a risk for smallpox occurring as a result of a deliberate release by terrorists exists; however, this risk is low, and the population at risk for such an exposure cannot be determined.
  • ACIP also assumed that, regardless of the mode, magnitude, or duration of a terrorism release, the epidemiology of subsequent person-to-person transmission would be consistent with prior experience.

What are the Contraindications for Vaccination in the Pre-Event Program?

  • Smallpox vaccination is contraindicated for persons:
    • with a history or presence of eczema or atopic dermatitis;
    • who have other acute, chronic, or exfoliative skin conditions;
    • who have conditions associated with immunosuppression;
    • who are pregnant or breastfeeding;
    • who are aged <1 year; or
    • who have a serious allergy to any component of the vaccine.
  • According to the package insert (Wyeth Laboratories. Dryvax), the vaccine might contain trace amounts of polymyxin B, streptomycin, tetracycline, and neomycin, and the diluent contains glycerin and phenol.
  • Persons with inflammatory eye diseases can be at increased risk for inadvertent inoculation as a result of touching or rubbing the eye. Therefore, deferring vaccination of persons with inflammatory eye diseases requiring steroid treatment is prudent until the condition resolves and the course of therapy is complete

Are Certain Household Contacts, Including Children, a Contraindication?

  • Pre-event vaccination is contraindicated among persons with household contacts who have a history or presence of eczema or atopic dermatitis, irrespective of disease severity or activity; who have other acute, chronic, or exfoliative skin conditions; who have conditions associated with immunosuppression; or who are pregnant.
  • Household contacts include persons with prolonged intimate contact with the potential vaccinee (e.g., sexual contacts) and others who might have direct contact with the vaccination site.
  • The presence of an adolescent or child (including an infant) in the household is not a contraindication to vaccination of adult members of the household; the risk for serious complications from transmission from an adult to a child is limited. Nonetheless, ACIP recognizes that programs might defer vaccination of household contacts of infants aged <1 year because of data indicating a higher risk for adverse events among primary vaccinees in this age group, compared with that among older children .
  • The presence of a breastfeeding woman or a person with a vaccine component allergy in the household is also not a contraindication to vaccination of other household members.

What is ACIP's Position on Administrative Leave?

  • Administrative leave is not required routinely for newly vaccinated health-care personnel unless they: 
    • are physically unable to work because of systemic signs and symptoms of illness; 
    • have extensive skin lesions that cannot be covered adequately; or 
    • are unable to adhere to the recommended infection-control precautions.

Is Contact Transmission of the Vaccinia Virus a Significant Concern?

  • After primary smallpox vaccination, vaccinia virus can be isolated from the vaccination site, beginning with development of a papule (i.e., 2 to 5 days after vaccination) until the scab separates from the skin lesion (i.e., 14 to 21 days after vaccination).
  • Maximal shedding of the virus occurs 4 to 14 days after vaccination.
  • Data from the smallpox eradication era indicate that primary vaccinees were the major source of vaccinia infection among contacts, presumably because they had a larger or longer duration of viral shedding than did revaccinees
  • The data also indicate that secondary transmission of vaccinia virus occurs infrequently, especially from adults, and requires close contact.
  • Today, both the risk for transmission and the risk of a serious adverse event are greater because of a larger number of hospitalized patients with compromised immune systems.
  • After considering the data and the caveats noted previously, ACIP and HICPAC concluded that optimal infection-control practices should essentially eliminate the risk of vaccinated health-care workers transmitting vaccinia to patients, and that placing health-care workers on administrative leave could create staffing shortages that might pose a risk to patients.

What is the Most Critical Measure in Preventing Contact Transmission?

  • Consistent hand hygiene with antimicrobial soap and water or an approved alcohol-based hand-rub (i.e., one that contains >60% alcohol) after any contact with the vaccination site or with materials that have come into contact with the site and before patient contact.
  • Care should be taken to prevent contact with the site or contaminated materials from the site.

How Should the Vaccination Site be Covered and Cared for?

  • Health-care personnel providing direct patient care should keep their vaccination sites covered with gauze or a similar absorbent material in combination with a semipermeable dressing to absorb exudates that develop and to provide a barrier for containment of vaccinia virus to minimize the risk of transmission
  • Products combining an absorbent base with an overlying semipermeable layer can be used to cover the site.
  • Semipermeable dressings provide an effective barrier to vaccinia virus, but use of a semipermeable dressing alone is associated with maceration of the vaccination site and increased irritation and itching at the site, thereby causing touching, scratching, and possible contamination of the hands.
  • The vaccination site should be covered with gauze, a semipermeable dressing, and a layer of clothing during direct patient care until the scab separates.
  • Persons outside the patient-care setting (e.g., members of public health response teams not involved in patient care, or health-care workers who are not at work) can keep their vaccination sites covered with a porous dressing (e.g., gauze); hand hygiene remains critical in preventing inadvertent inoculation.
  • In nonpatient-care settings in which transmission of vaccinia is a concern because of close personal contact with children or other persons, the vaccination site should be covered with gauze or a similar absorbent material and covered with clothing. Hypoallergenic tape should be used for persons who experience tape hypersensitivity.
  • The vaccination site should be kept dry, although normal showering or bathing can continue.

How Often Should Dressings be Changed?

  • Dressings used to cover the site should be changed frequently (e.g., every 3--5 days or more frequently if exudates accumulate) to prevent buildup of exudates and consequent maceration.

Who Should Change the Dressings?

  • Hospitals should include a vaccination site-care component in their smallpox vaccination programs in which designated staff assess dressings for all vaccinated health-care workers daily (whether the workers are involved in direct patient care or in other duties), determine if dressings need changing (e.g., when accumulation of purulent material is visible or the integrity of the dressing has been disrupted), and change the dressing, if indicated.
  • When feasible, staff responsible for dressing changes for teams should be vaccinated, but having nonvaccinated staff change dressings is acceptable.
  • All persons handling bandages should observe contact precautions.

What are the Special Concerns for Women of Child Bearing Age?

  • Any woman who believes she might be pregnant or who wants additional assurance that she is not pregnant should perform a urine pregnancy test by using her first-morning--void urine on the day scheduled for vaccination.
  • These tests could be made available at the prescreening and vaccination sites to avoid cost or other barriers to testing.
  • Women should be informed that a negative urine pregnancy test cannot exclude a very early pregnancy, and therefore, they and their health-care providers should not base a decision regarding their pregnancy status solely on a urine pregnancy test result.
  • Smallpox vaccination during pregnancy should not ordinarily be a reason to terminate pregnancy.

Should All Potential Vaccines be Tested for AIDS?

  • ACIP does not recommend mandatory HIV testing before 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 unsure of their HIV infection status.
  • Information regarding local testing options should be provided to all potential vaccinees, including sites where testing is performed at no cost.

Should Vaccinees Donate Blood?

  • The FDA has recommended that vaccinees be deferred from donating blood for 21 days or until the scab has separated.
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