Smallpox Vaccine

What is the smallpox vaccine?

The smallpox vaccine is an immunization you can get to help protect you against infection by the smallpox virus.

Routine smallpox vaccination among the American public stopped in 1972 when no more cases of smallpox were being reported in the US. The US government then provided the vaccine only to a few hundred scientists and medical professionals who were doing research with smallpox and similar viruses.

In 2001 the US government decided to prepare for the possible release of the smallpox virus by bioterrorists. Such a release of smallpox could start a deadly epidemic. The US government has ordered production of enough smallpox vaccine to immunize the American public in the event of a smallpox outbreak.

Smallpox is a very serious illness that can spread from person to person by coughing or sneezing. It causes high fever, tiredness, headache, backache, and a rash. The rash can cause severe, permanent scarring. Smallpox is fatal for about 1 of every 3 people who get the disease.

The smallpox vaccine is made from a virus called vaccinia. This virus is related to the smallpox virus. The vaccine contains live vaccinia virus. It does not contain the smallpox virus and cannot give you smallpox. However, the live virus in the vaccine may cause rash, fever, headache, and body aches. Rarely, it causes serious illness.

What are the benefits of the vaccine?

If you get the vaccine before you are exposed to smallpox, you will be protected against smallpox.

If you are exposed to the smallpox virus and get vaccinated within 3 days of the exposure, the vaccination usually prevents or reduces the symptoms of smallpox. Vaccination 4 to 7 days after exposure offers some protection from the disease or makes it less severe.

There is no cure for smallpox. Supportive care (IV fluids and antibiotics to prevent bacterial infections that can occur with smallpox) can help but will not cure the disease. The smallpox vaccine is the best protection you can get against smallpox.

Who should not get the smallpox vaccine?

Between 14 and 52 people of every 1 million people vaccinated for the first time have had life-threatening reactions to the vaccine. Based on past experience, it is estimated that 1 or 2 people in 1 million who receive the vaccine may die because of it. This is why healthcare providers carefully screen people before they are given the smallpox vaccine. People who are at high risk of complications are note given the vaccine.

You should not get the vaccine if:

• You are pregnant or breast-feeding. (It might harm the baby.)
• You are younger than 18 years of age (unless it is an emergency, such as a smallpox epidemic or attack of bioterrorism).
• You are allergic to the vaccine.
• You have a weakened immune system. You should not have the vaccine if you are HIV positive, are receiving chemotherapy for cancer, are taking medicines to suppress your immune system, or have had a transplant. If you are taking chemotherapy for a condition other than cancer, ask your healthcare provider if you should have the vaccine.
• You have heart disease.

How is the vaccine given?

You will not get a shot. Instead, your healthcare provider will dip a two-pronged needle into the vaccine and prick your skin 15 times. The poking is not deep, but it will cause a slight amount of bleeding and a small sore spot on your skin. The vaccine usually is given in the upper arm.

A red, itchy bump will develop at the vaccine site in 3 or 4 days. In a week, the bump becomes a blister, fills with pus, and begins to drain. During the second week, the blister begins to dry up and a scab forms. The scab falls off in the third week, leaving a small scar. If you are being vaccinated for the first time, the area of your skin that shows a reaction may be larger than if you are being revaccinated.

The live vaccinia virus is present at the vaccination site for up to 3 weeks after you get the vaccine. During this time the virus can spread to other parts of the body or to other people by direct contact. To help protect yourself from side effects and to keep from spreading the virus to others:

• Follow your healthcare provider's instructions for caring for the spot where you got the vaccine.
• Keep the vaccination site covered with a loose bandage until the dry scab forms. Healthcare workers involved with direct patient care should cover the loose gauze bandage with a semipermeable dressing.
• Try to avoid touching the site of the vaccination.
• For 3 weeks after your vaccination, always wash your hands with soap and water before you have direct contact with others.

What are the side effects or risks of the vaccine?

The vaccine does have some side effects and risks. Mild reactions you may have are:

• sore arm
• redness in the area where the vaccine was given
• large, sore glands in the armpits
• mild fever
• body aches.

These mild reactions usually go away without treatment.

In the past, about 1,000 people of every 1 million people vaccinated for the first time had reactions that were serious but not life-threatening. These reactions, which might need medical care, include:

• A vaccinia rash or outbreak of sores limited to one area. This is caused by touching the vaccination site and then spreading the vaccinia virus by touching another part of the body. It usually occurs on the genitals or face. It can happen in the eyes and damage sight or lead to blindness.
• A widespread rash. This can happen when the virus spreads from the vaccination site into the blood. Sores can then break out on more than one part of the body. This reaction is called generalized vaccinia.
• A toxic or allergic rash that can take various forms. This problem is called erythema multiforme.

You are more likely to have more serious side effects if:

• You have had skin conditions such as eczema or atopic dermatitis.
• You are pregnant.
• You are less than 18 years old.
• You are allergic to the vaccine.
• You have a weakened immune system.

Medical experts are exploring the possibility that the smallpox vaccine might cause inflammation of the heart or the membrane covering the heart. The Centers for Disease Control (CDC) recommends that anyone who has just received the smallpox vaccine should see a healthcare provider right away if they start having chest pain, shortness of breath, or other symptoms of cardiac disease.

How should I protect my family and myself if someone I'm close to is getting the vaccine?

Take these precautions for 2 to 3 weeks, until the vaccinated person's scab drops off:

• Don't touch the spot where they got the vaccine until it's healed. Don't touch bandages, clothing, towels, or any material that might have come into contact with the live virus. If you accidentally touch one of these things, wash with soap and warm water right away.
• If you share a bed with the vaccinated person, be sure they are wearing a gauze bandage held in place with first-aid adhesive tape over the vaccination site. For extra protection they can wear a shirt or pajamas that cover the site.
• Keep a separate laundry hamper for clothing, towels, or bedding that have come in contact with the vaccination site or drainage from the site. Wash these items in warm water with detergent or bleach. Wash your hands carefully after touching these items.
• Remind the person who got the vaccine to follow the instructions for caring for the site and for hand washing. The vaccination site often gets itchy, so they may scratch, rub, or touch the site. If their hand is contaminated and they touch you, you can get vaccinia.