smallpox vaccine

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Pronunciation: SMALL pox

What is the most important information I should know about this vaccine?

You may not be able to receive this vaccine if you are pregnant, or if you have a weak immune system caused by disease (such as cancer, HIV, or AIDS) or by having a bone marrow transplant.

Some side effects of smallpox vaccine may lead to severe disability, permanent nerve damage, and/or death. Call your doctor at once or seek emergency medical attention if you have a severe headache, vision problems, flu symptoms, muscle weakness, chest pain, irregular heartbeats, swelling in your feet, changes in your mental status, or any sudden problems with hearing or speech.

Smallpox vaccine is a "live" vaccine, and the virus can "shed" from your injection site. Until the scab falls off, your vaccination sore will be contagious and could spread the virus to others for up to 21 days. Get medical help if someone in your household shows signs of smallpox: skin rash, fever, headache, body aches.

What is smallpox vaccine?

Smallpox is a serious, contagious, and sometimes fatal infection caused by virus. Smallpox causes fever and a blistering skin rash. These blisters contain virus and can make the infected person highly contagious.

Smallpox is spread from person to person through direct contact, or by coming into contact with infected bodily fluids or contaminated objects such as clothing or bedding. A person with early symptoms of smallpox may or may not be contagious. Once the person forms a smallpox skin rash, the chance of spreading the disease increases until the last smallpox scab has fallen off.

The smallpox vaccine is used to help prevent this disease. This vaccine works by exposing you to a small dose of the virus, which causes the body to develop immunity to the disease. This vaccine will not treat an active infection that has already developed in the body.

The smallpox vaccine contains live "vaccinia" virus (a virus similar to smallpox). For this reason, the vaccination site (the place on your skin where the vaccine is injected) will be contagious and can spread the virus to other parts of your body or to other people.

Like any vaccine, the smallpox vaccine may not provide protection from disease in every person.

The smallpox vaccine is not currently given as a routine vaccination because the dedicated use of smallpox vaccine in the first half of the 20th century has virtually eliminated the disease. The last case of smallpox in the United States occurred in 1949. The last reported case of smallpox worldwide occurred in 1977.

Recent concerns that smallpox virus might be used as a weapon of bioterrorism has led U.S. health officials to take precautions for a smallpox outbreak. The smallpox vaccine is currently recommended for military and civilian personnel who work in high-threat areas, and in healthcare and safety workers who may provide first-response care in an outbreak. Smallpox vaccine is also recommended for laboratory workers who may be exposed to the smallpox virus or closely related viruses.

What should I discuss with my healthcare provider before receiving smallpox vaccine?

You should not receive this vaccine if you have ever had a life-threatening allergic reaction to any vaccine containing vaccinia virus.

Smallpox vaccine is not approved for use by anyone younger than 16 or older than 65 years old.

You may not be able to receive smallpox vaccine if you have severe immunosuppression (a weak immune system) or if you have had a bone marrow transplant. If you have a high risk of exposure to smallpox, you may need to receive the vaccine even if you have a weak immune system.

To make sure smallpox vaccine is safe for you, tell your doctor if you have:

  • a heart condition such as coronary artery disease, congestive heart failure, or chest pain (angina);
  • a history of heart attack, stroke, or "mini-stroke";
  • at least 3 heart risk factors such as smoking, diabetes, high cholesterol, high blood pressure, or a family history of heart disease in a person younger than 50;
  • a weak immune system;
  • leukemia, lymphoma, or other types of cancer;
  • HIV/AIDS;
  • a skin disorder such as eczema (atopic dermatitis);
  • a skin wound, burn, infection such as impetigo or shingles (herpes zoster);
  • a condition for which you have recently used a steroid eye drop;
  • an allergy to neomycin or polymyxin B;
  • close contact with a pregnant woman, or anyone who has a weak immune system or a skin disorder such as eczema;
  • close contact with an infant younger than 12 months old;
  • if you are pregnant or breast-feeding; or
  • if you have recently received cancer chemotherapy or radiation treatment.

Using this vaccine during pregnancy could harm the unborn baby. However, if you are at a high risk for infection with smallpox during pregnancy, your doctor should determine whether you need this vaccine.

It is not known whether smallpox vaccine passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

How is this vaccine given?

Smallpox vaccine is not given with a needle and syringe, as most other vaccines are. Instead, the smallpox vaccine is given using a two-pronged needle that is dipped into the vaccine solution and then used to prick the skin several times to deliver the vaccine into the shallow layers of skin. These needle sticks are not deep, but they will cause some soreness and minor bleeding.

Smallpox vaccine usually is given in the skin of your upper arm. You will receive this injection in a doctor's office or other clinic setting.

Within 3 to 4 days after receiving this vaccine, you should see a small red bump on your skin where the needle was placed. This bump may itch and it will gradually grow larger and form a blister filled with pus that will eventually drain. During the second week the blister should dry up and form a scab. After the scab falls off during the third or fourth week, you will most likely have a small scar.

Call your doctor at once if you have any unexpected skin changes or or severe irritation or signs of infection where the needle stick was placed. Also call your doctor if you have an outbreak of skin sores or blisters anywhere on your body.

Keep your vaccination sore covered at all times with a gauze bandage held in place with first aid tape, especially while the sore is draining pus. The bandage should allow air to flow through it to keep your vaccination sore dry. This bandage will provide a barrier to protect against spreading the virus to other people or to other parts of your own body. Change your bandage every 1 to 3 days to keep the sore clean and dry.

Smallpox vaccine contains a live form of the virus, which can "shed" from your injection site. This means that after you receive the vaccine and until your scab falls off, your vaccination sore will be contagious and could spread the virus to anything or anyone who touches it. The virus can also spread to other parts of your body that come into contact with your vaccination sore. This period of contagion may last for up to 21 days after you received the vaccine.

Wear a shirt at all times to cover your vaccination sore while it is healing. If you share a bed with someone, wear a shirt or pajamas to keep from spreading the virus to your bedding or to the other person.

Do not apply ointments or salves to the sore. Use a waterproof bandage to cover the sore while you are bathing. Apply a dry gauze bandage after bathing.

Always wash your hands thoroughly with soap and hot water after touching your vaccination sore, changing your bandages, or handling clothing, towels, or other fabrics that have come into contact with your sore. You may also use an alcohol-based hand sanitizer.

A vaccination sore can transfer smallpox virus to bandages, clothing, bedding, towels, wash cloths, or furniture.

Throw away used bandages in a sealed plastic bag placed in a garbage can that children and pets cannot reach. Do not allow anyone else to handle your used bandages.

Do not share towels, clothing, or other personal items while your vaccination sore is healing. Use a separate laundry basket or hamper for your clothing, towels, and bedding. All of your laundry should be washed in hot water with detergent and bleach (if possible) to get rid of any smallpox virus remaining on these items.

Get medical help if someone in your household shows any symptoms of smallpox, such as skin rash, fever, headache, or body aches. These may be signs that the virus has spread to that person or to something in the household that the person has touched.

When your scab falls off, place it in a sealed plastic bag and throw it away. Wash your hands with soap and hot water afterward.

This vaccine can cause false results on a skin test for tuberculosis. Tell any doctor who treats you if you have received a smallpox vaccine within the past 4 to 6 weeks.

What happens if I miss a dose?

Since smallpox vaccine is usually given as a single dose, you are not likely to be on a booster schedule. If a vaccination sore does not form on your skin where the needle stick was placed, the smallpox vaccine may not be effective and you may need to be re-vaccinated. Call your doctor if you do not develop a sore within 5 days after receiving your smallpox vaccine.

What happens if I overdose?

Since this vaccine is given by a healthcare professional, an overdose of smallpox vaccine is unlikely to occur.

What should I avoid after getting smallpox vaccine?

Avoid touching your vaccination sore and then touching another person. The smallpox virus in the vaccination sore is highly contagious. Do not scratch or pick at the vaccination sore, as this will greatly increase the risk of spreading the virus to other parts of your body or to other people.

Avoid touching the sore and then touching other parts of your body (especially your eyes or genital area) until you have washed your hands. Accidentally spreading the virus to your eyes can lead to permanent vision loss.

Do not donate blood or organs for at least 30 days after receiving smallpox vaccine.

What are the possible side effects of smallpox vaccine?

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

You should not receive a booster vaccine if you had a life-threatening allergic reaction after the first vaccine. Keep track of any and all side effects you have after receiving this vaccine. If you ever need to receive a booster dose, you will need to tell the doctor if the previous dose caused any side effects.

Becoming infected with smallpox is much more dangerous to your health than receiving the vaccine to protect against it. Like any medicine, this vaccine can cause side effects.

Some side effects of smallpox vaccine may lead to severe disability, permanent nerve damage, and/or death. Call your doctor at once or seek emergency medical attention if you have:

  • sudden eye problems or changes in your vision;
  • flu-like symptoms, severe headache;
  • confusion, hallucinations, increased sensitivity to light;
  • stiff neck or back, loss of balance or coordination;
  • slurred speech, problems with your senses (vision, hearing, smell);
  • muscle weakness or paralysis;
  • a seizure (blackout or convulsions);
  • unexpected or severe irritation, infection, or skin changes where the needle stick was placed;
  • an outbreak of skin sores or blisters anywhere on your body;
  • signs of a heart problem --chest pain, cough, irregular heart rate, feeling tired or short of breath (even with mild exertion), swelling in your legs or feet; or
  • severe skin reaction --fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common side effects may include:

  • pain, redness, swelling, or itching where the vaccine was injected;
  • numbness in the vaccinated arm;
  • general ill feeling, tiredness;
  • feeling hot or cold (shivering);
  • nausea, vomiting, diarrhea, constipation;
  • mild headache;
  • dizziness; or
  • swollen glands.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report smallpox vaccine side effects to the Centers for Disease Control at 404-639-3670 or 404-639-2888. You may also report vaccine side effects to the US Department of Health and Human Services at 1-800-822-7967.

What other drugs will affect smallpox vaccine?

Before receiving this vaccine, tell the doctor about all other vaccines you have recently received.

Also tell the doctor if you have recently received drugs or treatments that can weaken the immune system, including:

  • an oral, nasal, inhaled, or injectable steroid medicine;
  • medications to treat psoriasis, rheumatoid arthritis, or other autoimmune disorders; or
  • medicines to treat or prevent organ transplant rejection.

This list is not complete. Other drugs may interact with smallpox vaccine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Where can I get more information?

Your doctor or pharmacist can provide more information about this vaccine. Additional information is available from your local health department or the Centers for Disease Control and Prevention.


Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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