In the United States, the Hib vaccine is recommended for all children younger than 5 years old. It offers the best protection against Hib, which is short for a bacteria called Haemophilus influenzae type b.
Different types of Haemophilus influenzae (H. influenzae)bacteria, including Hib, can lead to different kinds of infections with a range of severity. Some are mild, while others can be life-threatening.
Here’s everything you need to know about the Hib vaccine, including how it works, who should get it, and its safety and effectiveness.
What Is the Hib Vaccine?
The Hib vaccine protects against illnesses caused by H. influenzae type b. (Despite the name, H. influenzae is a bacteria, not a virus, and it does not cause the flu.)
The Hib vaccine stimulates the immune system to produce antibodies that can recognize Hib bacteria if there's a future exposure and ward off infection.
Full immunization in babies requires three or four doses, depending on the brand.
Hib bacteria usually live harmlessly in the nose and throat, but they can move to other parts of the body and cause different kinds of illnesses, all known as H. influenzae disease.
There are six types of H. influenzae bacteria, labeled a through f. Most people only need to worry about type b. It can cause these serious illnesses:
Meningitis An infection of the brain and spinal cord membranes may lead to brain damage, hearing loss, or even death. Prior to the Hib vaccine, infection with Hib bacteria was the leading cause of bacterial meningitis in children under 5 years old in the United States.
Epiglottitis An infection causes swelling of the epiglottis, the small flap in the throat, potentially blocking the airway and leading to difficulty breathing.
Bloodstream Infections These can result in sepsis, a life-threatening condition in which the body’s excessive response to infection causes injury to organs.
Cellulitis A deep skin infection causes painful swelling.
Infectious Arthritis Also called septic arthritis, this is a painful infection of the joint.
Anyone can get H. influenzae, but serious cases, including Hib, mostly happen in children younger than 5 and adults 65 or older. Children under 1 have the highest rates of infection.
Although experts don’t know why, Black, Alaska Native, and Native American children have increased rates of serious disease.
Hib spreads through respiratory droplets when an infected person coughs or sneezes, or through close contact with respiratory secretions. People who aren’t sick but have the bacteria in their nose and throat can still pass the bacteria to others; that’s how H. influenzae spreads in most cases. It can also spread to people who have close and prolonged contact with a person who has H. influenzae disease.
The Centers for Disease Control and Prevention (CDC) recommends that all children younger than 5 receive the Hib vaccine, starting at 2 months of age.
The vaccine may also be recommended for older children and adults with certain medical conditions who are unvaccinated.
These medical conditions include the following:
Asplenia One dose of Hib vaccine should be given to people who have anatomical or functional asplenia (a condition in which the spleen is absent or not working properly) or who are undergoing an elective splenectomy (removal of the spleen) if they have not previously received the Hib vaccine. The vaccine should be administered 14 or more days before a splenectomy if possible.
Sickle Cell Disease This inherited blood disorder impacts hemoglobin, the protein that carries oxygen in the red blood cells. Serious problems related to sickle cell disease include blocked blood flow, pain, stroke, lung problems, eye problems, and kidney disease.
Stem Cell Transplant People with cancer who are recipients of a hematopoietic stem cell transplant should be vaccinated with a three-dose series of Hib vaccine 6 to 12 months afterward if the procedure was successful, regardless of vaccination history, with at least four weeks between doses. A hematopoietic stem cell transplant (also called bone marrow transplantation or stem cell transplantation) is a cancer treatment used to restore stem cells that are killed in chemotherapy or radiation treatment.
Most children should receive the Hib vaccine, but there are a few exceptions:
Infants Under 6 Weeks Old Hib vaccination is not recommended for newborns.
Anyone With Severe Allergies Anyone who has had a severe allergic reaction (anaphylaxis) to a previous dose of the Hib vaccine or has a severe allergy to any part of a Hib vaccine should not get the vaccine.
Most Healthy Adults The Hib vaccine is not routinely recommended for healthy adults who are unvaccinated, including those with HIV. That’s because these people have typically already been exposed to Hib bacteria and developed immunity.
The Hib vaccine is typically given in a series of three or four doses during early childhood to ensure long-term protection.
First Dose 2 months old
Second Dose 4 months old
Third Dose 6 months old (for certain brands of the vaccine)
Final Dose 12 to 15 months old
It’s important to follow the recommended vaccination schedule to ensure complete protection against Hib infections.
The Hib vaccine is highly effective in producing immunity to Hib bacteria. More than 95 percent of infants develop antibody levels high enough to protect against disease.
Research suggests that the Hib vaccine is over 90 percent effective against invasive (severe) Hib disease in infants who receive the entire series of doses.
The protection provided by the Hib vaccine is long-lasting, although experts don’t know the exact duration. Adults do not need a booster of the Hib vaccine.
The Hib vaccine has been used for decades, and its safety record is well established.
As with any medicine, there is a small chance that the vaccine could cause a serious reaction. However, getting the vaccine is much safer than getting Hib.
Most side effects of the Hib vaccine are mild and go away within a few days. These include the following:
Redness, swelling, or tenderness at the injection site
Mild fever
Serious side effects, such as severe allergic reactions, are extremely rare.
The cost of the Hib vaccine varies depending on the provider and location. However, most health insurance plans in the United States cover the full cost of the vaccine for children. Medicaid also typically covers the vaccine.
For those without insurance, the cost can vary, but vaccines are often available through public health programs at a lower cost.
The Hib vaccine is available at pediatricians' offices, clinics, and public health departments. It is typically administered during routine well-child visits. Check with your healthcare provider or visit the CDC’s vaccine-finder tool for more information on where to get the vaccine.
The Hib vaccine helps prevent serious and potentially life-threatening infections caused by H. influenzae type b bacteria, including infections of the blood and meningitis.
The vaccine is safe and highly effective, and provides long-lasting protection.
Children should receive the vaccine starting at 2 months of age, with a full series of three or four shots completed by 12 to 15 months.
