Name: ACAM2000

Precautions While Using ACAM2000

It is very important that your doctor check your progress at regular visits to make sure this vaccine is working properly and to check for unwanted effects .

This vaccine may cause serious heart problems in some patients. Check with your doctor right away if you are having chest pain or discomfort; dizziness; fast or irregular heartbeat; fever and chills; shortness of breath; sweating, weakness; or trouble breathing .

Tell your doctor if you smoke cigarettes or other tobacco products. The risk of heart problems is increased in people who smoke .

You should not receive this vaccine if you are using medicines that weaken your immune system, such as steroids, radiation, or cancer medicines .

You should not become pregnant for at least 3 months after receiving this vaccine without first checking with your doctor. There is a chance that this vaccine may cause problems during pregnancy. If you think you have become pregnant, tell your doctor right away .

This vaccine contains neomycin and polymyxin B. Make sure your doctor knows if you have had an allergic reaction to these medicines .

This vaccine contains a live virus. The virus can cause an infection in other parts of your body or in other people if you touch the vaccination site and then touch your body or other people. Always cover the vaccination site with a bandage. Wash your hands thoroughly after changing the bandage or after touching the vaccination site. Your doctor will tell you how to care for the vaccination site. Make sure you understand the directions and follow them carefully. Avoid contact with people who are sick or have infections until the scab falls off (usually 2 to 4 weeks after vaccination). Talk to your doctor about this if you have concerns .

You must wait at least 30 days before you can donate blood, use a hot tub or swim, handle a baby, or breastfeed .

Before you have any medical tests for syphilis or a tuberculin (TB) skin test, tell the medical doctor in charge that you have received this vaccine. The results of these tests may be affected by this vaccine .

FDA Approves ACAM2000

The U.S. Food and Drug Administration has licensed ACAM2000, a new vaccine to protect against smallpox, a highly contagious disease with the potential to be used as a deadly bioterror weapon.

The vaccine, ACAM2000, is intended for the inoculation of people at high risk of exposure to smallpox and could be used to protect individuals and populations during a bioterrorist attack. It will be included in the Center for Disease Control and Prevention's (CDC) Strategic National Stockpile of medical supplies.

A worldwide vaccination program eradicated smallpox in the population. The last case of naturally occurring smallpox in the U.S. was in 1949 and the last case in the world was reported in Somalia in 1977. Known stockpiles of the virus are kept only in two approved labs in the United States and Russia. The CDC considers it a Category A agent, meaning it presents one of the greatest potential threats for harming public health.

Smallpox is caused by the variola virus, a virus that emerged in human populations thousands of years ago. It spreads through close contact with infected individuals or contaminated objects, such as bedding or clothing. There is no FDA-approved treatment for smallpox and the only prevention is vaccination.

The symptoms of smallpox typically began with high fever, head and body aches. A rash followed that spread and progressed to raised bumps and pus-filled blisters that crusted, scabbed, and fell off after about three weeks, leaving a pitted scar. The fatality rate historically was about 30 percent, according to the CDC.

ACAM2000 is made using a pox virus called vaccinia, which is related to but different from the virus that causes smallpox. The vaccine contains live vaccinia virus and works by causing a mild infection that stimulates an immune response that effectively protects against smallpox without actually causing the disease.

The vaccine is derived from the only other smallpox vaccine licensed by FDA, Dryvax, approved in 1931 and now in limited supply because it is no longer manufactured.

Although smallpox vaccination ended in the United States in 1972 because it was no longer needed for prevention, the U.S. military resumed vaccination of at-risk personnel in 1999, after concluding that the disease posed a potential bioterrorism threat.

ACAM2000 was studied in two populations: those who had never been vaccinated for smallpox and those who had received smallpox vaccination many years earlier. The percentage of unvaccinated persons who developed a successful immunization reaction was similar to that of Dryvax. ACAM2000 also was found to be acceptable as a booster in those previously vaccinated for smallpox.

Because ACAM2000 contains live vaccinia virus, care must be taken to prevent the virus from spreading from the inoculation site to other parts of the body, and to other individuals.

To minimize known risks, the vaccine licensing is subject to a Risk Minimization Action Plan (RiskMAP). The RiskMAP requires providers of the vaccine and patients to be educated about these and other risks. The RiskMAP also requires patient education through an FDA-approved Medication Guide for those who receive the vaccine.

The Medication Guide explains the proper care of the vaccination site and provides information about serious side effects that can occur with ACAM2000. In studies, about 1 in 175 healthy adults who received smallpox vaccine for the first time developed inflammation and swelling of the heart and/or surrounding tissues (myocarditis and/or pericarditis). Of the 10 affected adults, four had no symptoms and at the end of the study, all but one had their symptoms resolve.

ACAM2000 is manufactured by Acambis Inc. of Cambridge, England and Cambridge, Mass. Dryvax was made by Wyeth Laboratories Inc. based in Madison, N.J.


Who should not get the ACAM2000 smallpox vaccine?

  • In an emergency, you should be vaccinated if you are at high risk for getting smallpox disease even if you have health problems (except if you have certain problems with your immune system as discussed below).
  • Your healthcare provider may not give you ACAM2000 if you have problems with your immune system. You may have immune system problems if you:
    • have leukemia
    • have lymphoma
    • have had a bone marrow or organ transplant
    • have cancer that has spread
    • have HIV, AIDS
    • have cellular or humoral immune deficiency
    • are being treated with radiation
    • are being treated with steroids, prednisone, or cancer drugs

For the Consumer

Applies to smallpox vaccine: injection powder for solution, injection powder for suspension

Along with its needed effects, smallpox vaccine (the active ingredient contained in ACAM2000) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking smallpox vaccine:

More common
  • Feeling unusually cold
  • shivering
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
Less common
  • Agitation
  • anxiety
  • back pain
  • blindness
  • blistering, peeling, or loosening of skin
  • blue or pale skin
  • blurred vision
  • changes in vision
  • chest discomfort
  • chest pain, possibly moving to the left arm, neck, or shoulder
  • confusion
  • convulsions (seizures)
  • cough
  • diarrhea
  • difficult or labored breathing
  • dizziness
  • drowsiness
  • fast heartbeat
  • fever and chills
  • hallucinations
  • headache
  • irritability
  • itching
  • joint or muscle pain
  • loss of consciousness
  • mood or mental changes
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • shortness of breath
  • skin rash that is encrusted, scaly, and oozing
  • sore throat
  • sores, ulcers, or white spots in the mouth or on the lips
  • stiff neck
  • tightness in the chest
  • trouble breathing
  • unusual tiredness or weakness
  • vomiting
  • wheezing

Some side effects of smallpox vaccine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Decreased ability to exercise
  • difficulty having a bowel movement (stool)
  • difficulty with moving
  • flushing or redness of the skin
  • general feeling of discomfort or illness
  • itching, pain, redness, or swelling at the vaccine site
  • muscle aching or cramping
  • muscle stiffness
  • nausea
  • rash
  • swollen joints
  • unusually warm skin

Usual Adult Dose for Smallpox Prophylaxis

1 drop applied by percutaneous multiple puncture technique (scarification).

Usual Geriatric Dose for Smallpox Prophylaxis

1 drop applied by percutaneous multiple puncture technique (scarification).

Routine nonemergency vaccination is not recommended for geriatric individuals. There are no absolute contraindications to vaccinations in persons with a high-risk exposure or during an outbreak emergency.

Usual Pediatric Dose for Smallpox Prophylaxis

1 drop applied by percutaneous multiple puncture technique (scarification).

less than 12 months: Routine nonemergency vaccination is contraindicated.
1 year to 18 years: Routine nonemergency vaccination is not recommended.

There are no absolute contraindications to vaccinations in persons with a high-risk exposure or during an outbreak emergency.

Renal Dose Adjustments

Data not available

Smallpox Vaccine Levels and Effects while Breastfeeding

Summary of Use during Lactation

The Centers for Disease Control and Prevention recommends that nursing mothers not receive the smallpox vaccine, even if they are pumping their milk and feeding it to their infant by bottle feeding. If a woman received smallpox vaccine during pregnancy or breastfeeding, she should avoid breastfeeding and handling any baby for at least 3 to 4 weeks until the vaccination scab has separated from the vaccination site. The breasts can be pumped to maintain the milk supply, but the milk should be discarded.[1][2][3]

If a close contact of the nursing mother receives the smallpox vaccine should wash their hands with soap and warm water after direct contact with the vaccination site, or anything that has touched the vaccination site (bandages, clothing, towels, bedding, etc.). This is will help prevent the spread of vaccinia virus to contacts, including young babies. If a breastfeeding mother who has had close contact with a person recently vaccinated against smallpox develops a rash, she should check with her healthcare provider to determine if the rash is related to the smallpox vaccine. If she has a vaccine-related rash, breastfeeding should not take place until all scabs from the rash have fallen off.[3]

Drug Levels

Maternal Levels. Smallpox vaccine has not been studied in lactating women. Live vaccinia virus can be inadvertently transmitted from a lactating mother to her breastfed infant. Infants are at high risk of developing serious complications from live vaccinia smallpox vaccination.[4]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

One 5-month-old breastfed infant acquired a vaccinia lesion on her upper lip, tongue and cheek after her mother developed vaccinia lesions on both areolas. The mother's infection apparently originated from the father who had been vaccinated about 10 days prior. The exact mechanism of transmission was not apparent.[5]

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.


1. Wharton M, Strikas RA, Harpaz R, Rotz LD, Schwartz B, Casey CG et al. Recommendations for using smallpox vaccine in a pre-event vaccination program. Supplemental recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Healthcare Infection Control Practices Advisory Committee (HICPAC). MMWR Recomm Rep. 2003;52:1-16. PMID: 12710832

2. Acambis I. Medication Guide. ACAM2000 Smallpox (Vaccinia) Vaccine, Live. Version 1.0. 2007.

3. Centers for Disease Control and Prevention. Questions and answers about smallpox vaccination while pregnant or breastfeeding. 2009.

4. Acambis I. ACAM2000 (Smallpox [Vaccinia] Vaccine, Live) package insert. 2007.

5. Garde V, Harper D, Fairchok MP. Tertiary contact vaccinia in a breastfeeding infant. JAMA. 2004;291:725-7. PMID: 14871916

Smallpox Vaccine Identification

Substance Name

Smallpox Vaccine

Drug Class