Hib (H. influenzae Type B) Vaccine

Despite its name, the bacterium called Haemophilus influenzae type b or Hib does not cause the flu. It does, however, cause Hib disease, a serious health threat to children under the age of 5. Fortunately, the Hib vaccine, available since 1992, provides safe and effective protection against that threat.

What Is Hib Disease?

Hib disease is an invasive bacterial infection that at one time was the most common cause of bacterial meningitis; invasive means that germs spread to parts of the body that are normally germ-free. Meningitis is an infection of the membrane that covers the brain and spinal cord. Bacterial meningitis is a serious infection that can cause fever, decline in mental status, coma, and death. It kills from 3% to 6% of the children who have it. And even when children survive, many of them are left with serious nerve and brain damage that can range from blindness to paralysis to mental retardation.

In addition to meningitis, Hib can cause pneumonia; epiglottitis, which is an infection in the throat that can cause breathing difficulties; blood infection; bone infection; and joint infection leading to arthritis.

The Hib germ is spread in droplets that come from sneezing or coughing. Before use of the vaccine, there were abouty 20,000 cases of Hib disease each year in children under 5, 12,000 of which were meningitis, and about 1,000 deaths per year.

Can the Hib Vaccine Cause Hib Disease?

The Hib bacterium has a coating; the Hib vaccine is made from this coating, which, when bonded with a protein, can cause the body’s defenses to build up immunity to Hib. Since the whole bacterium isn’t used, it cannot cause Hib infection and so cannot cause Hib disease.

Is the Hib Vaccine Safe Otherwise and Can It Be Given With Other Vaccines?

The vaccine is safe. The most common side effects include soreness, swelling, or redness at the site of the injection. There are no serious side effects, and severe allergic reactions are rare.

It is safe to give the vaccine with other vaccines, and it is generally given as part of a child’s regular vaccination routine.

Who Should Get the Vaccine?

The CDC recommends that the vaccine be given to children under the age of 5. Ideally the first dose should be given at the age of 2 months.

Since Hib disease is very rare in older children and since most adults have antibodies for Hib in their system, the vaccine is not recommended for anyone 5 years old or older, unless they are at increased risk for Hib infection. Older children and adults at increased risk include:

• Anyone lacking proper splenic function, such as people with sickle cell disease or someone who has had the spleen removed.
• Anyone whose immune system has been suppressed due to a condition or by a treatment, such as for cancer.