Hib disease is a bacterial infection with Haemophilus influenzae type b that can be devastating in young children. It is preventable with a vaccine that is usually given in a series of 3 or 4 shots starting at 2 months of age.
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Table of Contents for Haemophilus influenzae type b (Hib)
How do you get Hib disease?
How many people get Hib disease every year?
What are the symptoms of Hib disease?
How soon do symptoms appear?
What are complications of Hib disease?
Is Hib disease contagious?
How is Hib disease treated?
How effective is the Hib vaccine?
What is the immunization schedule for Hib disease?
What are Hib vaccine names?
Hib disease is an infection that is caused by a bacteria called Haemophilus influenzae type b. Hib disease is rare in people over 5 years old, but in young children, it frequently causes bacterial meningitis, brain damage, disability, or death. There is a vaccine to prevent Hib disease.
Hib disease spreads from person-to-person through direct contact with an infected person or by breathing droplets when that person coughs or sneezes. Most infections are spread by people who do not have any symptoms but they have the Hib bacteria in their nose and throat.
In 2008, there were 30 cases of Hib disease reported in the United States in children under 5 years old. This represents a 99% drop in cases since the vaccine was introduced in 1987. Before the vaccine, about 20,000 children got Hib disease and 1,000 children died from it.
Hib disease might not cause any symptoms if the bacteria stays in the nose and throat. If the infection spreads to the lungs or bloodstream, serious symptoms will appear. This is called invasive Hib disease.
The symptoms of invasive Hib disease depend on where the infection has spread in the body (brain, throat, joints, skin, lungs, bones, etc).
Symptoms of a lung infection (pneumonia) may include:
- Fever and chills
- Shortness of breath or difficulty breathing
- Chest pain
- Muscle pain or aches
- Excessive tiredness
Symptoms of bloodstream infection (bacteremia) may include:
- Fever and chills
- Excessive tiredness
- Pain in the belly
- Nausea or vomiting
- Shortness of breath
Symptoms of a brain infection (meningitis) may include:
- Stiff neck
- Nausea and/or vomiting
- Increased sensitivity to light
- Altered mental status
- Infants may be lethargic, limp, not alert, irritable, or not eat
The symptoms of Hib disease can appear within a few days of exposure to a person who is infected with the bacteria. Sometimes the bacteria stays in the body for months without causing symptoms.
Hib disease is very serious. The bacteria spreads to the brain and causes meningitis in 50-65% of children, with symptoms including fever, decreased mental status, and stiff neck. The mortality rate is 2-5%, but 15-30% of survivors suffer permanent brain damage, blindness, deafness, or intellectual disability.
Another 17% of people with invasive Hib infections develop epiglottitis, an infection and swelling in the throat that can block the airways and cause suffocation. Hib disease can also cause joint infections (8%), skin infections (6%), pneumonia (15%), and bone infections (2%).
Hib disease is considered to be minimally contagious, but it can spread quickly among people who spend a lot of time together, like families or daycares.
Hib disease is diagnosed with a laboratory test on a sample of infected body fluid (blood or spinal fluid) and it is treated with antibiotics. Most people must be hospitalized. Around two-thirds of Hib infections result in meningitis, and 3-6% of all children with Hib meningitis die from the disease.
The first Hib vaccine was approved in the United States in 1985, but it was not very effective in infants under 18 months old. An improved conjugate Hib vaccine was approved in 1987. The Hib conjugate vaccine is what we use today. It is an inactivated vaccine that contains parts of the Hib bacteria that trigger immunity without causing an infection. There are many different Hib vaccines, including several that are combined with vaccines against other diseases.
More than 95% of infants will be protected against Hib disease after 2 or 3 doses of the vaccine.
Infants older than 6 weeks old should receive 3 to 4 doses of the Hib vaccine, depending on the brand and formulation. It is usually given at the ages of 2 months, 4 months, 6 months, and 12-15 months of age.
Unvaccinated children between 15 months and 59 months old should get 1 dose of the Hib vaccine. Hib disease is rare in healthy children over 5 years old, so the vaccine is not routinely recommended.
All conjugate Hib vaccines can be given interchangeably if the original brand is unknown or unavailable.
People older than 5 years old do not normally need a Hib vaccine. The vaccine is only recommended for people in certain high-risk groups, including people with sickle cell disease, no spleen, HIV infections, or recipients of a bone marrow transplant or hematopoietic stem cells.
The following is a list of Hib vaccines that are approved in the U.S:
- ActHIB® (Hib)
- Pentacel® (Hib-DTaP/IPV)
- PedvaxHIB® (Hib)
- Hiberix® (Hib) — Only for 4th booster dose
- MenHibrix® (Hib-MenCY)
The following is a list of Hib vaccines that are no longer available:
- Comvax® (Hib-HepB)
- ProHIBit® (Hib)
- HbOC® (Hib)
- HibTITER (Hib)
- OmniHIB (Hib)
Yes. It is very rare for the Hib vaccine to cause serious side effects. The vaccine is inactivated and it can’t cause Hib disease.
To learn more about the side effects associated with Hib vaccines, please visit this page: Hib Vaccine Side Effects.
The most common Hib vaccine side effects are warmth, redness, and swelling where the shot was injected (5-30%). Up to one out of 20 children (5%) develop a fever over 101ºF. Other common side effects include irritability, drowsiness, loss of appetite, or vomiting.
Hib vaccines can sometimes cause severe allergic reactions. The risk is estimated at fewer than 1 in a million doses. The symptoms appear in a few minutes or hours and may include hives, face and throat swelling, difficulty breathing, a fast heartbeat, dizziness, or weakness.
There have also been reports of severe side effects like convulsions or seizures, but it is unknown if they were caused by the Hib vaccine. Some of the combined vaccines (Pentacel, MenHibrix, Comvax, etc.) are also associated with Guillain-Barré Syndrome, Brachial Neuritis, and other side effects.