Haemophilus Influenzae: A-to-Z Guide from Diagnosis to Treatment to Prevention

Haemophilus influenzae (H flu) are common bacteria that cause a wide variety of infections in children. Other types of H flu remain very common.

Not long ago H influenzae type b (Hib) was the number one cause of bacterial meningitis. More than half of the cases of Hib infection in the United States involve bacterial meningitis. Thankfully, Hib disease has plummeted by more than 99 percent since the Hib vaccine was introduced in 1988 – in countries where the vaccine is used. Nevertheless, Hib remains a major worldwide problem.

What is it?

Haemophilus influenzae (H flu) are common bacteria that cause a wide variety of infections in children. Type b has been the cause of the most serious diseases, but can be effectively prevented by immunization. Other types of H flu, especially non-typable H flu, remain very common.

Although the name of these bacteria sounds similar to the influenza virus, the two are unrelated and very different. When the bacteria were first discovered back in 1892, they were incorrectly thought to be the cause of the influenza pandemic occuring at that time. This was disproved a decade before the influenza virus was eventually discovered, but the name for the bacteria had already been in use for a generation, and the name stuck.

Who gets haemophilus influenzae?

Anyone can get an H flu infection, but infants and young children are at the highest risk.

What are the symptoms of haemophilus influenzae?

H flu is among the most common cause of ear infections and sinus infections. These bacteria can cause many other types of infections including septic arthritis, pneumonia, meningitis, and conjunctivitis.

Is haemophilus influenzae contagious?

Yes. H flu infections can spread by direct contact, respiratory droplets, and body fluids.

How long does haemophilus influenzae last?

These tend to be acute, not chronic infections. The length of infection depends on the location of the infection and the type of H flu.

How is haemophilus influenzae diagnosed?

The diagnosis is often suspected based on the history and the physical exam. It can be confirmed by detecting the bacteria in blood, spinal fluid, or other body fluid.

How is haemophilus influenzae treated?

These infections are treated with antibiotics. Most of the time the antibiotics are given in tablet or liquid form. For serious infections, IV antibiotics may be needed.

How can haemophilus influenzae be prevented?

The Hib vaccine can prevent most serious cases of H flu disease. Those in close contact with people with serious H flu disease should receive preventive antibiotics.

General hygiene measures can decrease the spread of H flu. Specific preventive measures are available for some types of infection (see ear infections, for instance).

Hib, H flu

Last medical review on: January 07, 2014
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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