What is haemophilus influenzae
Haemophilus influenzae, a type of bacteria, can cause many different kinds of infections. These infections range from mild ear infections to severe diseases, like bloodstream infections. Haemophilus influenzae type B (Hib) is a potentially serious infection that can cause meningitis (inflammation around the brain), epiglottitis (inflammation in the lower throat), and pneumonia. Haemophilus influenzae type B is rare in the US since babies are routinely vaccinated against it. The Centers for Disease Control and Prevention (CDC) recommends haemophilus influenzae type b vaccination for all children younger than 2 years old. The CDC also recommends a haemophilus influenzae type b booster shot when children are 12 through 15 months old.
Bacterial infections caused by haemophilus influenzae type b are usually spread by sneezing and coughing and are responsible for childhood illnesses such as meningitis and epiglottitis (swelling of the epiglottis in the back of the throat). They can also cause some cases of pneumonia and ear infections. Despite the name, haemophilus influenzae bacteria, do not cause the flu or influenza. Haemophilus influenzae is not the same as influenza (the flu). Influenza is caused by a virus, whereas haemophilus influenzae is a bacteria.
Haemophilus influenzae type b (Hib) bacteria live in the back of the throat of healthy people. Sometimes they invade the body and cause infections. Haemophilus influenzae type b most commonly affects children who are aged under 5. Infection with haemophilus influenzae type b can be serious. The infection can attack the membranes around the brain (meningitis), epiglottis at the back of the throat (epiglottitis), infection of the lungs (pneumonia), infection of the lining surrounding the heart (pericarditis), infection of the joints (septic arthritis), infection of the bones (osteomyelitis), tissues under the skin (cellulitis), or can invade the bloodstream, causing bacteremia or septicemia (sepsis). This can happen quickly and can be fatal. Haemophilus influenzae can also be a common cause of ear infections in children and bronchitis in adults.
The haemophilus influenzae bacteria can be spread by healthy people who carry the bacteria, as well as those who are ill with a haemophilus influenzae type b infection. Inhaling the infected droplets or transferring them into your mouth from a contaminated surface can allow the bacteria to spread further into your body, causing one of the infections mentioned above.
Before the haemophilus influenzae type b (Hib) vaccine was introduced, haemophilus influenzae type b was the most common cause of bacterial meningitis in young children. But haemophilus influenzae type b infections are now rare in United States. CDC recommends haemophilus influenzae type b (Hib) vaccine for all children younger than 2 years old in the United States. Babies should start getting the haemophilus influenzae type b (Hib) vaccine at 2 months old (they need multiple doses for best protection). CDC recommends Hib vaccination for all children younger than 5 years old. Older children and adults usually do not need a haemophilus influenzae type b vaccine, unless they have certain medical conditions. Talk to your or your child’s healthcare professional about what is best for your specific situation.
Even with appropriate treatment, some haemophilus influenzae infections can result in long-term problems or death. For example, blood infections (bacteremia) can result in loss of limbs. Meningitis (infection of the tissue covering the brain and spinal cord) can cause brain damage or hearing loss. A small number (3 to 6 in 100) of children with meningitis caused by haemophilus influenzae type b die from the disease. Those who survive may have long-term problems, such as hearing loss, seizures and learning disabilities.
Complications are rare and typically not severe for bronchitis and ear infections caused by haemophilus influenzae.
How haemophilus influenzae spreads
People spread haemophilus influenzae, including haemophilus influenzae type b, to others via droplets from the nose or throat. This happens when someone who has the haemophilus influenzae bacteria in their nose or throat coughs or sneezes. People who are not sick but have the haemophilus influenzae bacteria in their noses and throats can still spread the bacteria. That is how haemophilus influenzae spreads most of the time.
The haemophilus influenzae bacteria can also spread to people who have close or lengthy contact with a person with haemophilus influenzae disease. But since vaccination was introduced it’s been very uncommon for someone to catch haemophilus influenzae type b. Those most at risk are unvaccinated children under 5 and elderly people aged over 65.
People at increased risk of haemophilus influenzae
Haemophilus influenzae, including haemophilus influenzae type b, disease occurs mostly in babies and children younger than 5 years old. Adults 65 years or older, American Indians, Alaska Natives, and people with certain medical conditions are also at increased risk. Those medical conditions include:
- Sickle cell disease
- Asplenia (no spleen)
- HIV infection
- Antibody and complement deficiency syndromes (rare conditions that affect the body’s ability to fight infections)
- Cancer requiring treatment with chemotherapy, radiation therapy, or bone marrow stem cell transplant.
Haemophilus influenzae causes
Haemophilus influenzae disease refers to any infection caused by haemophilus influenzae bacteria. There are six identifiable types of haemophilus influenzae (named a through f) and other non-identifiable types (called nontypeable). The one that people are most familiar with is haemophilus influenzae type b or Hib.
These bacteria live in people’s nose and throat, and usually cause no harm. However, the bacteria can sometimes move to other parts of the body and cause infection.
Experts do not know how long it takes after haemophilus influenzae enter a person’s body for someone to get sick. However, it could take as little as a few days before symptoms appear.
The most common types of invasive disease caused by haemophilus influenzae are:
- Pneumonia (lung infection)
- Bacteremia (bloodstream infection)
- Meningitis (infection of the tissue covering of the brain and spinal cord)
- Epiglotittis (swelling in the throat)
- Cellulitis (skin infection)
- Infectious arthritis (inflammation of the joint)
Haemophilus influenzae type b prevention
Vaccination against haemophilus influenzae type b is recommended for all babies from 2 months of age. They will need 3 doses – at 2, 4, and 6 months – and a booster at 15 months (for haemophilus influenzae type b (Hib) only vaccines). People with certain medical conditions should also be vaccinated against haemophilus influenzae type b.
Children diagnosed with haemophilus influenzae type b should stay away from childcare or school until they have finished their course of antibiotics. If you are in close contact with someone who is infected with haemophilus influenzae type b, a short course of antibiotics may prevent you from catching the disease.
Haemophilus influenzae type b vaccine
The Food and Drug Administration licensed 4 haemophilus influenzae type b vaccines for use in the United States. Three of the vaccines protect against haemophilus influenzae type b disease only, while one vaccine includes protection against other diseases. Your child will get multiple doses; the number depends on the brand given. Doctors can give the first dose as early as 6 weeks, if needed. Doctors can give any of the haemophilus influenzae type b-only vaccines to older children and adults that need haemophilus influenzae type b vaccination.
Hib-only Vaccines
- PedvaxHIB®: Doctors give three doses to children who are 2 through 15 months old.
- ActHIB®: Doctors give four doses to children who are 2 through 15 months old.
- Hiberix®: Doctors give four doses to children who are 2 through 15 months old.
Combination Vaccines
A combination vaccine contains two or more vaccines in a single shot in order to decrease the number of shots given.
- Pentacel®: Doctors give four doses to children who are 2 through 18 months old. This vaccine protects against Hib disease, diphtheria, tetanus, pertussis (whooping cough), and polio.
Young Children
Children younger than 5 years old need multiple doses of a Hib vaccine. The first dose haemophilus influenzae type b vaccine can be administered as early as age 6 weeks. CDC recommends doses at the following ages 1:
- 2 months
- 4 months
- 6 months (if needed; depends on brand)
- 12 through 15 months
Infants 2 through 6 months of age should receive either:
- A 3-dose series of ActHib®, Hiberix®, or Pentacel®
- A 2-dose series of PedvaxHib®
The booster dose will be dose 3 or 4 depending on vaccine type used in the primary series.
Older Children and Adults
Older children and adults usually do not need a Hib vaccine. CDC recommends haemophilus influenzae type b (Hib) vaccination for two groups of older children and adults:
- People with certain medical conditions who are unvaccinated
- People who receive a bone marrow transplant
These medical conditions include:
- Sickle cell disease
- Asplenia (no spleen)
- HIV infection
- Antibody and complement deficiency syndromes (rare conditions that affect the body’s ability to fight infections)
- Cancer requiring treatment with chemotherapy, radiation therapy, or bone marrow stem cell transplant
Talk to your or your child’s healthcare professional about what is best for your specific situation.
Who should not get haemophilus influenzae type b?
Because of age or health conditions, some people should not get certain vaccines or should wait before getting them. Read the guidelines below and ask your or your child’s healthcare professional for more information.
Babies younger than 6 weeks old should not get a haemophilus influenzae type b vaccine. In addition, tell the person who is giving you or your child a haemophilus influenzae type b vaccine if:
- You or your child have had a life-threatening allergic reaction or have a severe allergy.
- Anyone who had a life-threatening allergic reaction after a previous dose of a haemophilus influenzae type b vaccine should not get another dose.
- Anyone with a severe allergy to any part of a haemophilus influenzae type b vaccine should not get this vaccine. Your or your child’s healthcare professional can tell you about the vaccine’s ingredients.
- You or your child are not feeling well.
- People who have a mild illness, such as a cold, can probably get the vaccine. People who have a more serious illness should probably wait until they recover. Your or your child’s healthcare professional can advise you.
Haemophilus influenzae type b vaccine side effects
Most people who get a haemophilus influenzae type b vaccine do not have any problems with it. With any medicine, including vaccines, there is a chance of side effects. These are usually mild and go away on their own within a few days, but serious reactions are possible.
Mild problems
Mild problems following haemophilus influenzae type b vaccination are uncommon. If they occur, they usually begin soon after you or your child receive the shot. They can last up to 2 or 3 days, and include:
- Reactions where the doctor gave the shot
- Redness
- Warmth
- Swelling
- Fever
Problems that could happen after getting any injected vaccine
- People sometimes faint after a medical procedure, including vaccination. Sitting or lying down for about 15 minutes can help prevent fainting, and injuries caused by a fall. Tell your healthcare professional if you or your child:
- Feels dizzy
- Has vision changes
- Has ringing in the ears
- Some people get severe pain in the shoulder and have difficulty moving the arm where the doctor gave the shot. This happens very rarely.
- Any medicine can cause a severe allergic reaction. Such reactions from a vaccine are very rare, estimated at about 1 in a million doses. These types of reactions would happen within a few minutes to a few hours after the vaccination.
- As with any medicine, there is a very remote chance of a vaccine causing a serious injury or death.
How well do haemophilus influenzae type b vaccines work?
Vaccines that help protect against haemophilus influenzae type b disease work well, but cannot prevent all cases.
Studies show haemophilus influenzae type b vaccination protects nearly all (between 93 and 100 in 100) children from serious infections, called invasive haemophilus influenzae type b disease 2. Protection decreases over time. Children need a dose between 12 and 15 months old to maintain high levels of protection during early childhood.
Haemophilus influenzae type b vaccines are highly effective in preventing invasive haemophilus influenzae type b disease, including meningitis (infection of the tissue covering the brain and spinal cord). haemophilus influenzae type b disease was once a leading cause of bacterial meningitis among U.S. children younger than 5 years old. Every year about 20,000 young children got invasive haemophilus influenzae type b disease and about 1,000 died. More than half of the children who developed invasive haemophilus influenzae type b disease were younger than one year old. Today, less than 50 cases of haemophilus influenzae type b disease occur each year in young children in the United States. Most of these cases are in children who did not get any or all recommended doses of haemophilus influenzae type b vaccine.
Haemophilus influenzae symptoms
Haemophilus influenzae, including haemophilus influenzae type b (Hib), can cause many different kinds of infections. Symptoms depend on the part of the body that is infected. For instance:
- Meningitis is an infection and swelling of the tissues that cover the brain and spinal cord. Until a vaccine became available, haemophilus influenzae type b was the most common cause of bacterial meningitis in the United States. It occurs most often in children between the ages of 6 months and 5 years. Symptoms of meningitis typically include sudden onset of:
- Fever
- Headache
- Stiff neck
- Back pain
- Nausea with or without vomiting
- Photophobia (eyes being more sensitive to light)
- Altered mental status (confusion)
- Seizures
- Excessive sleepiness
- Decrease in appetite
- Babies with meningitis may be irritable, increase in crying, vomit, feed poorly, or appear to be slow or inactive. In young babies, doctors may also test the child’s reflexes, which can be abnormal with meningitis.
- Epiglottitis is a rare but serious inflammation in the throat, affecting the epiglottis (a flap of tissue at the back of the throat) and occurring most often in children 2 to 4 years of age. Your child’s first symptoms will probably be a severe sore throat and fever (typically a temperature greater than 101°F [38.3°C]), followed by a raspy or harsh sound called stridor during breathing. As the epiglottis becomes swollen, it can make swallowing difficult, trigger drooling, and may block normal breathing. Some children with epiglottitis have choked to death. Prompt treatment usually can prevent this.
- Pneumonia. Symptoms of pneumonia (lung infection) usually include:
- Fever and chills
- Cough
- Shortness of breath or difficulty breathing
- Sweating
- Chest pain
- Headache
- Muscle pain or aches
- Excessive tiredness
- Loss of appetite
- Bacteremia. Bacteremia is an infection of the bloodstream. Symptoms of bacteremia include:
- Fever and chills
- Excessive tiredness
- Pain in the belly
- Nausea with or without vomiting
- Diarrhea
- Anxiety
- Shortness of breath or difficulty breathing
- Altered mental status (confusion)
- Bacteremia from H. influenzae can occur with or without pneumonia.
- Osteomyelitis: Symptoms include swelling, inflammation and pain over the bone
- Cellulitis: The person will have – red, hot, swollen and tender area of skin.
- Other haemophilus influenzae type b infections. Haemophilus influenzae, including haemophilus influenzae type b (Hib) can also cause infection in the joints (septic arthritis), infection of the lining surrounding the heart (pericarditis), ear infections (otitis media) and infection of skin of the face (cheek or around the eye). Signs of infections in these areas include fever, swelling, pain, and redness along with a drastic decrease in energy and activity.
Both meningitis and epiglottis can develop quickly and are fatal if they are not treated. If you think your child has one of these conditions, take them straight to a hospital emergency department or call your local emergency services number and ask for an ambulance.
Haemophilus influenzae diagnosis
Doctors usually diagnose haemophilus influenzae, including haemophilus influenzae type b (Hib), infection with one or more laboratory tests. Haemophilus influenzae type b is diagnosed with a blood test or by performing a lumbar puncture to sample the fluid, known as cerebrospinal fluid (CSF), that sits around the brain and spinal cord.
Haemophilus influenzae treatment
Treatment for haemophilus influenzae, including haemophilus influenzae type b will depend on the type of infection. If you are diagnosed with haemophilus influenzae, including haemophilus influenzae type b, you will normally need to take antibiotics for 10 days. Depending on how serious the infection is, people with haemophilus influenzae infection may need care in a hospital. You may also need medicine to control the fever, pain relief, extra fluids and help with breathing.
Other treatments may include:
- Breathing support
- Medication to treat low blood pressure
- Wound care for parts of the body with damaged skin
When haemophilus influenzae cause milder infections, like bronchitis or ear infections, doctors may give antibiotics to prevent complications.
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