by Katie Porterfield
November 29, 2011

What is Hib?
Haemophilus influenzae type B (commonly referred to as Hib) is a bacterial infection that most often occurs in children under the age of 5. According to the CDC, before the Hib vaccine was available, Hib was the leading cause of bacterial meningitis (an inflammation of the tissue that covers the brain and spinal cord) in children. Hib can also cause pneumonia (lung infection), epiglottitis (a severe throat infection), and infections of the blood, joints, bones, and the sac around the heart (pericarditis).

Why should I vaccinate my child?
Before the Hib vaccine was introduced in 1987, the CDC reports that a child’s risk for getting invasive Hib disease by the age of 5 was 1 out of 200. In fact, there were about 20,000 cases of invasive Hib a year, and two-thirds of those cases were meningitis (a disease that once killed 600 children a year).

With the introduction of the vaccine, however, the incidence of Hib has declined by 99 percent. From 1996 through 2000, there were on average 68 cases of Hib disease a year in children under the age of 5. Despite these low rates, the CDC urges parents to continue to vaccinate their children to prevent a resurgence of Hib.

In December 2007, a voluntary recall by Merck, the Hib vaccine manufacturer, caused a Hib vaccine shortage in the U.S. The CDC responded by recommending that health care providers defer the 12 to 15 month booster dose for children not at high risk for Hib disease. In 2009, the CDC reinstated the Hib booster dose for children ages 12 to 15 months. During that time, at least six unvaccinated children in New York and Pennsylvania were infected and two died in what was the largest outbreak of Hib in recent years. The vaccine shortage likely removed just enough of the protective effect of widespread immunizations (herd immunity) to make unvaccinated children more vulnerable.

How many doses will my child receive?
The Hib vaccine is typically given as a series of three or four shots, beginning with a primary series that includes two or three doses (depending on the brand of the vaccine) and concluding with a booster shot.

When is the vaccine given?
According to the CDC, children should get the Hib vaccine at:

• 2 months of age

• 4 months of age

• 6 months of age (this dose may not be needed, as it depends on which brand of the vaccine is used)

• 12 to 15 months of age (booster)

What are the possible side effects?
Side effects of the vaccine include redness, warmth, or swelling at the injection site (reported in up to 25 percent of children) and a fever over 101° F (reported in up to 1 out of 20 children). If these symptoms occur, they usually begin within a day of the vaccination and may last 2–3 days. Parents are advised to apply a cool, wet washcloth to the painful area and give acetaminophen or ibuprofen (as directed by the child’s health care provider; dosage for babies is based on a child’s weight not age) for pain and fever. If symptoms persist, parents should contact their child’s health care provider right away.

When should I call a doctor?
Parents should immediately alert their child’s health care provider if the child experiences difficulty breathing, hoarseness, wheezing, hives, paleness, weakness, a rapid heartbeat, or dizziness. Such side effects would likely occur within a few minutes to a few hours of receiving the vaccination. Parents should also contact their child’s health care provider if the child has a high fever or displays unusual behavior.

Katie Porterfield is a freelance writer and former magazine editor in Nashville, Tennessee. She is mom to twin boys.