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Haemophilus influenzae type B, or Hib, is a bacteria that can cause infections. It usually occurs children under five years old. Hib can lead to:

• Meningitis
• Pneumonia
• Swelling in the throat
• Other types of infections
• Death

People can carry Hib bacteria and not know it. These germs can spread from person to person. They usually spread through droplets from an infected person. Sickness will probably not occur when the germs stay in the nose and throat. They can cause serious problems when they spread into the lungs or the bloodstream.

Before the vaccine, severe Hib disease affected about 20,000 US children under age five.

Symptoms include:

• Fever
• Drowsiness
• Vomiting
• Stiff neck
• Other symptoms, depending on the part of the body affected

The Hib vaccine is made from inactive parts of the bacteria. It is injected into the muscle.

In general, children should get doses at:

• 2 months
• 4 months
• 6 months
• 12-15 months

In some cases, your child may only need three doses. This depends on which brand the doctor uses.

If a dose is missed, talk to the doctor. There are different catch-up schedules depending on the brand and your child's age.

This vaccine is not routinely recommended for children aged five years or older or adults. But, it may be given if you or your child was not vaccinated before and your child has certain conditions, such as:

• Sickle cell disease
• Bone marrow transplant
• HIV
• Removal of the spleen

Like any vaccine, the Hib vaccine can cause serious problems, such as a severe allergic reaction. Most people do not have any problems. Some people have redness, warmth, or swelling near the injection site, as well as a fever.

Acetaminophen (eg, Tylenol) is sometimes given to reduce pain and fever that may occur after getting a vaccine. In infants, the medicine may weaken the vaccine. Discuss the risks and benefits of taking acetaminophen with the doctor.

The following people should not get the vaccine:

• Children younger than six weeks
• People who have ever had a life-threatening allergic reaction to a previous dose of Hib vaccine
• People who are moderately to severely ill (They need to wait until they have recovered.)

Antibiotics may be given to certain infants and young children who have not been vaccinated and have been exposed to the disease.

In the event of an outbreak, public health officials will determine who is at risk and vaccinate people.