Questions & Answers

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When did Hib vaccine become available?
The first Hib vaccine was licensed in the United States in 1985; however, it was not very effective in children age 18 months and younger. The first improved Hib vaccine, a conjugate vaccine, was licensed in December 1987.

What type of vaccine is it?
The Hib conjugate vaccine is made by chemically bonding a polysaccharide (sugar) to a protein. The sugar is one that makes up the surface capsule of the bacterium. This is an inactivated vaccine.

How is this vaccine given?
The Hib vaccine is given as an injection into the muscle.

Is there more than one brand of Hib vaccine?
There are several formulations of Hib vaccine, including two that are combined with another vaccine (one with DTaP and another with hepatitis B). The number of doses needed depends on the brand of vaccine given.

All conjugate Hib vaccines may be given interchangeably if the original brand is unknown or unavailable.

Who should get this vaccine?
All infants should receive doses of Hib vaccine as part of their routine immunization (unless they have a medical reason not to). As Hib disease is rare in children older than age five years, Hib vaccine is not routinely recommended for people age five years or older.

Is Hib vaccine recommended for anyone age five years or older?
Older children and adults who are at increased risk for invasive Hib disease should be vaccinated. High-risk individuals include those with asplenia (e.g., sickle cell disease, postsplenectomy), immunodeficiency, immunosuppression from cancer chemotherapy, and HIV infection. A previously unvaccinated person with one of these high-risk conditions should be given at least one dose of any licensed Hib vaccine.

How many doses of Hib vaccine are required for the childhood series?
Three to four doses are needed, depending on the brand of Hib vaccine used. Children should get Hib vaccine at two months, four months, usually six months (depending on the brand of vaccine), and 12–15 months of age. Hib vaccine should never be given to a child younger than six weeks of age, as this might reduce his/her response to subsequent doses.

My 18-month-old toddler has never received Hib vaccine. Does she still need to get the series?
All children age 12 months or older, and younger than age five years, should receive at least one dose of Hib vaccine. The number of doses needed to complete the series depends on the child’s current age.

Will receiving the Hib shot protect my baby from ever getting meningitis?
No, because meningitis is also caused by other viruses and bacteria. Hib vaccine will only protect against meningitis caused by Hib.

Who recommends this vaccine?
The Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) all recommend this vaccine.

How safe is this vaccine?
Adverse events following receipt of Hib conjugate vaccine are uncommon. The most common reactions are local reactions at the injection site, such as warmth, redness, and swelling, occurring in 5%–30% of recipients. Up to one out of 20 children may develop a fever over 101°F.

How effective is this vaccine?
All the Hib vaccines licensed for use are good at producing immunity to invasive Hib disease. More than 95% of infants will be protected after two or three doses.

Who should NOT receive Hib disease vaccine?
Anyone who has ever had a life-threatening allergic reaction to a previous dose of Hib vaccine should not get another dose.

Children younger than six weeks of age should not get Hib vaccine because a dose given at this time may reduce the infant’s response to subsequent doses.

Persons with a moderate or severe acute illness should postpone receiving the vaccine until their condition has improved.

Can the vaccine cause Hib disease?
No. Only the entire Hib bacterium can cause Hib disease. Hib vaccine is a fractional vaccine, containing only part of the Hib microbe.

Questions and answers about hib disease

Technically reviewed by the Centers for Disease Control and Prevention, April 2007