Questions and Answers About Smallpox Vaccine


What is smallpox vaccine?
The smallpox vaccine helps the body develop immunity to smallpox. The vaccine is made from a virus called vaccinia which is a “pox”-type virus related to smallpox. The smallpox vaccine contains the “live” vaccinia virus—other vaccines containing live virus include measles, mumps, and German measles. For that reason, the vaccination site must be cared for carefully to prevent the virus from spreading. Also, the vaccine can have side effects. The vaccine does not contain the smallpox virus and cannot give you smallpox. (Apr 28, 2003) How long is the vaccinia virus viable on clothing, towels, dressing, etc.? There is an experiment that attempts to shed light on this question. It is noted in a 1976 Western J. Med article and referenced in Sepkowicx NEJM study on nosocomial transmission, Johnson et al 1976 Nosocomial Vaccinia Transmission. In this experiment smallpox vaccine was reconstituted, allowed to dry on a slide, then reconstituted after room temp incubation for 0-144 hours. At 78 hours saw drop in viability, at 144 hours, no longer viable. There has been no documented case of fomite transmission.

Vaccination and Clinic Operations

What is the current thinking on vaccinating the vaccinators?
Vaccinators can be vaccinated at the time they begin vaccinating but it may be preferable to vaccinate vaccinators earlier than that to eliminate the possibility that the vaccinators may be experiencing vaccine-related symptoms and not feel well enough to work for a few days (possibly up to 1/3), usually ~7-10 days after begin vaccinated. Each state will determine how they will vaccinate vaccinators.

Who specifically among the vaccination clinic staff should be vaccinated? Do we include all clerical staff, as well?
To minimize the clinical impact of inadvertent inoculation, should it occur, ACIP recommends that persons who will be handling and administering smallpox vaccine in the proposed pre-event smallpox vaccination program be vaccinated. It is not necessary for anyone not handling the smallpox vaccine to be vaccinated.

Are nurses the only ones who can administer smallpox vaccine?
The vaccine can be administered by nurses, doctors, or other licensed health care professionals. Whether or not non-clinical personnel can be used in a vaccination clinic is dependent on state laws. Local health agencies should consult with their state health department on what is allowable.

The Privacy Act statement says that all of the information on the patient screening form is voluntary. Is it truly voluntary? How does this work legally?
The screening worksheet is a voluntary tool for individuals considering vaccination. It is not collected and the information is not elicited. However, the Patient Medical History and Consent Form, does elicit information. Vaccinees are asked to provide demographic information, vaccination and medical history information, and are asked whether they have any of the conditions that would mean they should not be vaccinated. They also are asked to provide a consent signature acknowledging their agreement to proceed with vaccination.

Does CDC expect all adverse events will be entered into
If so, will the current form be modified to have smallpox specific information on it? All adverse event information should be entered in VAERS using the form as it currently stands.

Vaccine Administration

The Advisory Committee on Immunization Practices (ACIP) recommendations no longer match the product insert for ACAM2000. Which should I follow?
ACIP recommendations are considered by the CDC and, if the CDC chooses to adopt the recommendations as policy, they are published in the CDC’s Morbidity and Mortality Weekly Reports (MMWR). Any ACIP recommendations published in the MMWR are also official HHS/CDC recommendations, including those related to smallpox vaccination. However, since the bulk of the recommendations are still valid, there are no plans to update it, at this time, to accommodate the licensure of ACAM2000®. When it comes to instructions on how to administer the vaccine, providers are encouraged to refer to the package insert: iconexternal icon Can vaccinators immediately begin inoculating others after they’ve been vaccinated or should they wait a period of time and if so, how much time? They can begin vaccinating others immediately.

Should gloves be worn when administering smallpox vaccine?
Yes, gloves are recommended whenever there is a possibility of exposure to reconstituted smallpox vaccine. Persons administering the vaccine should wear gloves. After a person is vaccinated and the needle placed in a sharps container, gloves should be removed and discarded, hands should be disinfected with soap and water or a waterless hand product, and a new pair of gloves donned before the next person is vaccinated.

How do you document th
e dosage and route the administration of smallpox vaccine?
Document dosage as a “dose” or 0.0025ml, and route as percutaneous with bifurcated needle.

What bifurcated needles can be used with the smallpox vaccine? Is the CDC recommending that only the bifurcated needle accompanying the vaccine vials be used? What brand of needle has been approved for vaccination?
Vaccine kits will include 100 individually wrapped needles as part of the kit. Since each vial contains 100 doses of vaccine, this should be an adequate supply of needles. However, if a project area runs into problems, they should have their SNS coordinator contact the Strategic National Stockpile at the number provided in the shipping instructions.

Some documents say that no skin prep be done, in others it says use acetone. What can be used?
Alcohol, soap and water, or other chemical agents are not needed for preparation of the skin for vaccination unless the area is grossly contaminated. If needed, soap and water are the preferred cleaning agents. If any cleaning agent is used, the skin must be thoroughly dry in order to prevent inactivation of the vaccine.

With Dryvax® vaccine, there was discussion about using diluted vaccine (1:5 or 1:10) for mass vaccination. Can we do the same with ACAM2000®?
There are currently no protocols for using diluted ACAM2000®.

What is the ACIP recommendation for the number of needle sticks?
The Supplemental Recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Healthcare Infection Control Practices Advisory Committee (HICPAC) were published in the April 4, 2003, Recommendations and Report of the MMWR. “Recommendations for Using Smallpox Vaccine in a Pre-Event Vaccination Program” is posted on the CDC Web site: icon. The DryVax® vaccine discussed in this guidance is no longer available and has been replaced by ACAM2000®. ACAM2000® uses 15 insertions for both primary and revaccination and has no provision for additional insertions if no trace of blood is visible after vaccination. Providers are encouraged to read and follow the directions provided in the packet insert: iconexternal icon .

How do you designate between a “primary” versus “secondary” smallpox vaccinee?
With ACAM2000® there is no longer the need to differentiate between “primary” and “secondary” vaccinees. However, it is useful to know should an adverse event occur. A person is determined to be a primary vaccinee based on their medical history. If they don’t know or did not receive the smallpox vaccine previously, then they should be treated as a primary vaccinee. If they were born prior to 1971, they were most likely vaccinated, although this is not guaranteed. If there was no take on their previous smallpox vaccination, they are not considered previously vaccinated and should be treated as a primary vaccinee. If there was a take on the previous vaccination, they are considered a secondary vaccinee.

Some individuals are allergic to nickel. What is the composition of the bifurcated needle?
The Precision bifurcated vaccinating needle is manufactured of solid stainless steel wire.

What does the bifurcated needle look like?
The bifurcated needle is approximately 2-1/2 inches long with a very small two-pronged needle at one end. The prongs have a very small opening between them that holds the vaccine to be applied to the arm. The prongs are 1/16 inches long and are used to pierce the outer layer of the skin only. A photograph is available at icon.

What should be done if the vaccine is administered too rigorously or deep (if that is possible)?
If you feel that you’ve administered the vaccine too vigorously or deep, wait to see if a take occurred on day 6-8 and revaccinate if no take occurred.

If a newly reconstituted vial vaccine hasn’t gone into a more or less homogeneous solution/suspension after gently swirling it and letting it sit for 30 to 45 minutes, can it be used or should it be discarded?
To break up any clumps and to help facilitate a more uniform suspension, the vaccine product may be gently agitated with a bifurcated needle if the needle is sterile and discarded appropriately after use.

Why is the smallpox vaccination site recommended on the deltoid versus other places on the body? Are vaccinees allowed to choose the body site they prefer for vaccination?
The skin over the deltoid muscle or the posterior aspect of the arm over the triceps muscle is the preferred site for smallpox vaccination. The deltoid region offers ease of observation, ease of dressing changes, and is easier to keep dry while bathing or showering. Also, the arm is more easily left uncovered or lightly bandaged during the day than the thigh, hip or back. Consequently, a site on the arm may heal more rapidly. Vaccination on the upper arm also will allow for easy visualization of a vaccination scar in emergency situations where vaccination status may need to be quickly assessed. The CDC does not have enough information to determine the safety of administering smallpox vaccinations at sites other than the deltoid, therefore CDC recommends only using this site.

What if individuals being vaccinated have extensive tattoos over both arms? Can these individuals be vaccinated? If so, where should they be vaccinated?
CDC does not have a standard policy concerning tattoos. One can vaccinate over a tattoo, but it may change the appearance of the tattoo. It would seem prudent to inform the potential vaccinee that vaccination over a tattoo may change it, and that use of another site is not routinely recommended. If you wish to vaccinate persons at another body site, they should be informed that CDC has no data about what use of an altered site means in terms of local adverse events, or autoinoculation risk.

What should we do if the client becomes ill and/or faints before all punctures are made?
If they faint during the administration, the vaccinator should stop the procedure and then check on day 6-8 to see if enough vaccine was administered to illicit a take (i.e., a major reaction is seen). If not, revaccinate at that time.

What is the recommended timeframe for revaccination of non-takers?
If no evidence of vaccine “take” is apparent after 7 days, the person can be vaccinated again immediately or any time thereafter using 15 insertions, regardless of the vaccinee’s prior vaccination status (i.e. primary vs. revaccinee). If clinic logistics delay this time frame, revaccination can be delayed as necessary. Revaccination can be done in the same arm as the first dose.

How is the vaccine stopper to be stored so that it can be used to recap the smallpox vaccine vial?
Once the vial cap is removed, it should be placed with the top of the stopper facing down and stored in such a way that the cap is free of contamination and inadvertent handling. (For example, the cap could be placed between clean gauze pads.) Clean gloves should be worn while removing or replacing the cap.

Can federal employees be vaccinated by state Smallpox Vaccination Programs? What is the policy for federal employees of agencies outside of the Department of Health and Human Services?
The state health departments are responsible for deciding who should be vaccinated in their state smallpox vaccination program. The states can include federal employees as part of their program. When the state decides against vaccinating federal employees and the federal agency disagrees, the agency should contact the Assistant Secretary for Public Health Preparedness and Response, Office of the Secretary, Department of the Health and Human Services at (202) 401-5840.

Vaccine Candidates

Even though the public is not being vaccinated for smallpox at this time, what if a person insists?
Members of the general public who would like to be vaccinated now should check the Web site: http://www.clinicaltrials.govexternal icon to see if there is a clinical trial near them in which they are eligible to enroll. This is currently the only available option.

Why the restriction of smallpox vaccination to persons less than 65 years of age (and greater than 18 years)?
At this time the vaccine is not recommended for the general public. The original restriction was based on absence of studies about smallpox vaccination in the “geriatric” age group, which CDC defined as 65 years and greater. This cutoff was chosen for simplicity. However, if an individual older than 65 is asked to participate in a smallpox response team (and does not have a contraindication to receiving the vaccine,, they can volunteer and be vaccinated. At this time, vaccination against smallpox is only recommended for laboratorians who work with orthopox viruses, and public health and health care response team members. It is unlikely that smallpox response team members are under the age of 18, but can be older than 65. The vaccine manufacturer package insert states that smallpox vaccination is not recommended for routine use in geriatric populations. See package insert iconexternal icon. As more research becomes available, CDC will address general smallpox geriatric use and update the recommendation.

Will Level A and B Laboratory staff be required to get vaccinated?
No. Level A and B laboratory staff will not be required to be vaccinated, but vaccination will be offered through the Laboratory Response Network. Generally, however, the amount of virus in specimens for routine clinical laboratory testing, and not virus diagnostic testing, would be low and good laboratory safety practices should protect laboratory staff from exposure. For more information on laboratory safety practices, please see the “Biosafety” section of the Public Health Emergency Preparedness and Response Laboratory Information page at

Where can I get information about the military’s smallpox vaccination program?
Information is located on the Department of Defense (DoD) Smallpox Vaccination Program Web site at icon. Questions can be emailed directly to:; or call 1-877-GET-VACC (1-877-438-8222) TOLL FREE; 703-681-5101 DSN 761; Fax 703-681-4692; 8am EST – 6pm EST, Monday – Friday (except Federal holidays).

Does a vaccinated health care worker need to inform his patients of the vaccination?
This question was considered at the October 2002 ACIP meeting and the impression from this meeting was that health care workers did not need to inform patients of their vaccination status. Each institution should follow the procedures they use for other infections in health care workers that can be transmitted to and present a risk to patients, e.g. hepatitis B and HIV infection.

Page last reviewed: March 13, 2009