ACAM2000

Pronunciation: A-cam two-thou-zand
Generic name: smallpox and mpox (Vaccinia) vaccine, live
Dosage form: injection, powder, lyophilized, for solution (multidose)
Drug class: Viral vaccines

Medically reviewed by Carmen Pope, BPharm. Last updated on Sep 3, 2024.

What is the ACAM2000 smallpox/mpox vaccine?

ACAM2000 is a prescription vaccine that may be used to prevent smallpox and mpox disease in people of any age with a high chance of getting smallpox or mpox (previously called monkey pox).

• Talk to your healthcare provider about being vaccinated with ACAM2000 if you have a high chance of being exposed to smallpox and/or mpox.

ACAM2000 gained an extension of its FDA approval to include mpox on August 29, 2024. ACAM2000 was first approved for smallpox on September 4, 2007.

ACAM2000 side effects

The most common side effects of ACAM2000 are:

• vaccination site reactions, such as redness, pain, swelling, and itching at the vaccination site
• swollen lymph nodes
• fever
• headache
• muscle aches
• rash
• fatigue/tiredness
• feeling unwell.

These side effects are less likely to occur in people who have already been vaccinated with a smallpox/mpox vaccine compared to those who have never been vaccinated with this type of vaccine before.

Serious side effects and warnings

ACAM2000 carries a Boxed Warning for myocarditis and pericarditis.

The risk of experiencing serious vaccination complications must be weighed against the risks of
experiencing a potentially severe or fatal smallpox or Mpox infection. 

Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining outside the heart) have occurred with ACAM2000. Most cases have occurred within 1-2 weeks after vaccination. Symptoms of myocarditis and pericarditis include:

• Chest pain
• Shortness of breath or difficulty breathing
• Feelings of having a fast-beating, fluttering, or pounding heart

Symptoms of myocarditis and pericarditis may be different in children and may also include:

• Fainting
• Unusual and persistent irritability
• Unusual and persistent poor feeding
• Unusual and persistent fatigue or lack of energy
• Persistent vomiting
• Persistent pain in the abdomen
• Unusual and persistent cool, pale skin.

ACAM2000 contains live vaccinia virus (a “pox”-type virus) that can be spread to individuals who have close contact with the vaccinated individual. ACAM2000 can cause serious complications in vaccinated individuals and in their close contacts to whom the vaccine virus has spread.

Inflammation of the brain or spinal cord has also occurred in people vaccinated with ACAM2000.

Serious skin infections can also occur with ACAM2000 such as a rash caused by widespread infection of the skin (known as eczema vaccinatum), a buildup of inflamed tissue around the vaccination site that may at first look like a bullseye and will grow into a large, non-healing sore (known as progressive vaccinia).

There is a possibility that the vaccine virus from ACAM2000 may spread through the blood to other parts of your body and cause further side effects.

Because the vaccine has a live virus, care must be taken to avoid spreading the virus from the vaccination site to other people or other parts of the body, which may occur by trauma, scratching, or incorrect disposal of the dressing that covers the vaccination site. If the virus is spread to a person who should not get the vaccine, the side effects can be very serious and life-threatening. The result of accidental infection is a pock lesion or lesions at an unwanted site in the person being vaccinated or their close contact and resembles the vaccination site. Selfinoculation occurs most often on the face, eyelid, nose, anus, and mouth, but lesions at any site of traumatic inoculation can occur. Accidental infection of the eye (which may cause swelling of the cornea causing watery painful eyes and blurred vision, scarring of the cornea, and blindness).

There is a risk of the unborn baby dying if pregnant females are vaccinated with ACAM2000.

Severe allergic reactions after vaccination with ACAM2000 are also possible. Tell your healthcare provider immediately if you experience any swelling of your face or throat, a skin rash, a fast heart rate, or difficulty breathing.

To report suspected side effects, contact Emergent BioSolutions at 1-877-246-8472 and medicalinformation@ebsi.com or VAERS at 800-822-7967 and https://vaers.hhs.gov.  

Related/similar drugs

Who should not get ACAM2000?

Do not receive ACAM2000 if you have:

• A severely weakened immune system (for example, you are undergoing a bone marrow transplantation)
• A weakened immune system that requires you to isolate.

People who may have a weakened immune system include those who:

• 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.

If you are unable to receive ACAM2000 because of a problem with your immune system, talk to your healthcare provider about other options to protect against smallpox and mpox.

Before receiving ACAM2000

Before receiving ACAM2000, tell your healthcare provider about all your medical conditions, because some may increase your risk of having side effects from the vaccine. Tell them if you:

• have had problems after previous doses or are allergic to ACAM2000 or any part of ACAM2000 such as antibiotics neomycin or polymixin B
• have heart problems or a history of heart problems
• have a weakened immune system
• have skin problems such as eczema, atopic dermatitis, burns, impetigo, contact dermatitis, chickenpox, shingles, psoriasis, or uncontrolled acne
• are taking steroid eye drops or ointment
• have a child that is less than 1 year old
• are pregnant or become pregnant within 6 weeks after vaccination.
• are breastfeeding.

Tell your healthcare provider if any of the above apply to you or to anyone with whom you live, work, or have close contact.

How is ACAM2000 given?

ACAM2000 is given "percutaneously". This means your healthcare provider will make 15 pokes in the skin of your upper arm with a needle containing a small drop of ACAM2000.

• The pokes are not deep but will cause a drop of blood to form. This is called the vaccination site.
• It is important to care for the vaccination site properly (see below) so that the virus doesn't spread to other parts of your body or other people.
• Because the vaccination site contains a live virus, you can infect another part of your body or other people until the scab falls off.

If you need medical care in the month after your vaccination, tell your healthcare provider you just got a smallpox vaccination.

Certain people, such as laboratory workers who work with smallpox, are at risk of being exposed to smallpox over a long period.

• These people may need a booster vaccination every 3 years to maintain protection against smallpox.

What to expect at your vaccination site after receiving ACAM2000.

If you have never been vaccinated with a smallpox/mpox vaccine before, the vaccination site will develop a small red, itchy bump in 2 to 5 days that will become a blister and fill with pus over the next few days.

• The blister then dries up and a scab forms which falls off within 3 to 6 weeks, leaving a scar.

If you have been vaccinated with a smallpox/mpox vaccine before, you may have a reduced response to ACAM2000.

• In most previously vaccinated people, a red, itchy bump forms at the vaccination site in 6 to 8 days, and a blister may not form.
• You will have still been successfully vaccinated and do not need another dose.

How do I care for my ACAM2000 vaccination site?

Your vaccination site is considered “infectious” from the time you get vaccinated until a scab forms and falls off and the skin at the vaccination site is fully healed. It is important to care for the vaccination site properly so that the virus doesn’t spread to other parts of your body or to others. 

It is important to ALWAYS:

• Wear gauze secured loosely with first-aid adhesive tape to cover the entire vaccination site.
• Wear sleeves to cover the bandage.
• Cover the vaccination site with a semipermeable dressing on top of the gauze to provide
  additional protection against the spread of the virus if you are a healthcare worker. The
  dressing should allow passage of air to the vaccination site, but not allow passage of fluid.
• Wash your hands with soap and warm water or alcohol-based cleansers after contact with
  the vaccination site, bandages or clothes, towels, or sheets that might be contaminated with
  the vaccine virus. Wear gloves when changing bandages or caring for your vaccination site.
• Change your gauze when it begins to soak through (at least every 1 to 3 days).
• Throw away gloves and used gauze, semipermeable dressings, and bandages in sealed
  plastic bags with a small amount of bleach to kill the virus.
• Cover the vaccination site with a waterproof bandage during bathing or showering. If the
  vaccination site gets wet, dry the site with toilet paper and flush it. Cover the vaccination
  site with a loose gauze bandage after bathing or showering to allow it to dry out.
• Use a waterproof bandage on the vaccination site while exercising if you exercise enough
  to cause sweat to drip.
• Wash clothing, towels, bedding or other items that may have come in contact with the
  vaccination site separately from other wash. Use hot water with detergent and bleach.
• Throw the scab away in a sealed plastic bag with a small amount of bleach when it falls off. Wash your hands afterward.
• Wear bandages or Band-Aids to cover the entire vaccination site.
• Wear sleeves to cover the site.
• Wash your hands, wash your hands, wash your hands.

What should I avoid after having my ACAM2000 vaccination?

Do not use creams or ointments on the vaccination site.

Do not scratch or pick at the vaccination site.

Do not touch or scrub the vaccination site while taking a bath or shower.

• It is best to cover the vaccination site with a waterproof bandage.
• If the vaccination site gets wet, dry the site with toilet paper and flush it. (Do not use a cloth towel because it can spread the virus.)
• Cover the vaccination site with a loose gauze bandage after bathing to allow it to dry out.

Do not use a bandage that blocks air from the vaccination site. This could cause the skin at
the vaccination site to soften and wear away.

For 6 weeks after ACAM2000 vaccination and until the vaccination site has healed, avoid:

• Getting pregnant or getting your partner pregnant
• Spreading the vaccine virus to unvaccinated individuals, especially infants (including while
  breastfeeding), pregnant individuals, and individuals with a weakened immune system. The
  virus can be spread by physical contact (including sexual contact) and by sharing a bed,
  clothes, towels, linen, or toiletries with unvaccinated people
• Donating blood or organs
• Swimming or hot tub use
• Rubbing, scratching, or touching the vaccination site. 

ACAM2000 may cause some tests for Tuberculosis (TB) or Syphilis to give the wrong result. If you need to be tested for TB or Syphilis within 6 weeks of receiving ACAM2000, tell your healthcare provider that you received ACAM2000.  

It is not known if the vaccine virus can be spread to cats, dogs, or other household pets, or whether pets can spread the virus to other people in the household.

• Try to keep the vaccine virus from reaching your pet by following the information about how to care for your vaccine site.

ACAM2000 ingredients

ACAM2000 active ingredients: live vaccinia virus grown in African Green Monkey kidney (Vero) cells.

Inactive ingredients: HEPES buffer, human serum albumin, sodium chloride, mannitol, trace amounts of the antibiotics neomycin and polymyxin B, Glycerin, and Phenol.

Who makes ACAM2000?

Emergent Product Development Gaithersburg Inc. makes ACAM2000.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer