HIB (Haemophilus influenzae type B) Vaccine

Summary

• It is a serious and often deadly disease, especially in infants and young toddlers.
• The vaccine is highly effective and has no known side effects.
• The disease still occurs whenever immunization rates fall.
  
• HIGHLY RECOMMENDED

The Hib vaccine is a vaccine against the Haemophilus influenzae type B bacterium. This germ used to infect thousands of infants and toddlers every year, causing sepsis (blood infection), meningitis, brain damage and death. A vaccine was first developed against this disease in 1985; there are currently several available. It is interesting that in a very short time, this disease has all but disappeared in children; young pediatricians likely never have never seen a single case through all their years of training and practice. However, the disease is returning to the U.S. in unvaccinated children.

The disease

Hib disease was the leading cause of bacterial meningitis in young children, and it infected about 20,000 children a year in the U.S. About 1 in 20 children infected died from the disease even despite antibiotic therapy; many more (about 25%) suffered brain damage. The germ also causes pneumonia and a dangerous throat infection called epiglottitis. The germ can be spread from person to person by coughing, sneezing, and breathing. A person can carry the germ without getting sick, and then a cold or the flu leads to the germ infecting the ears, sinuses, lungs, or bloodstream, where it quickly spreads, often causing meningitis.

The Vaccine

A polysaccharide vaccine was developed in 1985 that was not effective in children less than 18 months of age; unfortunately, these children are at the greatest risk of disease. In 1987, a conjugate vaccine was developed by attaching disease antigens to a carrier protein which causes the immune system to respond in a more effective manner. Conjugate vaccines tend to be effective in children under the age of 2, whereas polysaccharide vaccines are not. A total of 4 types of Hib conjugate vaccines have been developed; only 2 are currently available in the United States.

The two vaccines are roughly the same in effectiveness (though the manufacturers may argue that theirs is better).  There is a third brand of one type of HIB vaccine, for use only as the booster dose.

Schedule

The vaccine is given in either 3 or 4 doses, depending on the particular vaccine brand. It is given at 2 and 4 months of age. One brand requires a dose at 6 months; the other does not. The last dose is given at 12-15 months of age. If a child receives at least one dose at 15 months or older, no other doses are required.

How it is Given

The vaccine is injected into the muscle of the thigh or upper arm.

Side Effects

This vaccine has few if any side effects. It cannot cause any form of Hib disease, and it is not known to cause any serious reactions. It may cause low grade fever (101), redness, warmth, and/or slight swelling at the injection site. These mild reactions can start within one day and last 2-3 days.

Contraindications & Precautions

A person who has had a severe allergic reaction to a past Hib vaccine, or to any components of the Hib vaccine, should not get another dose. A child who is moderately or severely ill should delay the vaccination until he or she has recovered from the illness. They should not be given to children less than 6 weeks of age.

Risks vs. Benefits

The vaccine has no known serious side effects and has been proven to be safe and highly effective. The disease is common, serious, and often fatal. This disease has all but disappeared thanks to the vaccine and most children receiving it, which decreases the spread of the germ to others, including unimmunized children and infants too young to have received the vaccine. The benefits of this vaccine far outweigh the risks at this time.

My Recommendations

The Hib vaccine is a remarkable success story, virtually wiping out this very common and serious disease.  It has no side effects. The disease returns when and where immunization rates fall. I highly recommend this vaccine.

Resources

Hib (Haemophilus Influenzae type b) Vaccine Information Statement (CDC)

References

Prevention and Control of Haemophilus influenzae Type b Disease: Recommendations of the ACIP, 2014 MMWR, February 28, 2014, Vol 63, #RR01

Published May 2005. Last revised November 2016.