What is smallpox vaccine?
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.
Smallpox vaccine side effects
Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).
Call your doctor at once or seek emergency medical attention if you have:
sudden eye problems or changes in your vision;
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;
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; or
chest pain or pressure, fast or irregular heartbeats, or breathing problems.
Common side effects of smallpox vaccine may include:
pain, redness, swelling, or itching where the vaccine was injected;
fever, body ache;
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 vaccine side effects to the US Department of Health and Human Services at 1 800 822 7967.
Call your doctor at once or seek emergency medical attention if you have chest pain or pressure, fast or irregular heartbeats, or breathing problems.
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 4 weeks. Get medical help if someone in your household shows signs of smallpox: skin rash, fever, headache, body aches.
Before taking this medicine
You should not receive this vaccine if you have ever had a life-threatening allergic reaction to any vaccine containing vaccinia virus.
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.
Tell your doctor if you have ever had:
heart attack, or stroke;
a weak immune system;
leukemia, lymphoma, or other types of cancer;
a skin disorder such as eczema (atopic dermatitis);
a condition for which you have recently used a steroid eye drop or ointment;
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, plan to get pregnant, or breastfeeding; 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.
Ask a doctor if it is safe to breastfeed while using smallpox vaccine.
How is this vaccine given?
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.
Call your doctor at once if you have any unexpected skin changes 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. Change your bandage often 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 4 weeks after you received the vaccine.
Do not apply ointments 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.
A vaccination sore can transfer smallpox virus to bandages, clothing, bedding, towels, wash cloths, or furniture. Wear a shirt at all times to cover your vaccination sore while it is healing.
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.
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.
Smallpox vaccine dosing information
Usual Adult Dose for Smallpox Prophylaxis:
Administer 1 drop via scarification (percutaneous multiple puncture technique) in the upper arm over insertion of the deltoid muscle
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 receiving smallpox vaccine?
Avoid touching your vaccination sore and then touching another person. The smallpox virus in the vaccination sore is highly contagious.
Avoid touching the sore and then touching other parts of your body (especially your eyes or genital area) until you have washed your hands.
Do not donate blood for at least 30 days after receiving smallpox vaccine.
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;
medicines to treat or prevent organ transplant rejection.
This list is not complete. Other drugs may affect smallpox vaccine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
More about smallpox vaccine
- Check interactions
- Compare alternatives
- Side effects
- Dosage information
- During pregnancy
- Drug class: viral vaccines
- En español
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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.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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