Haemophilus influenzae, also called H. flu, is not the typical yearly flu. H. flu isn’t a virus; it’s a bacteria that can cause a wide variety of illnesses, from a sinus or ear infection to pneumonia and meningitis. There are a few different types of H. flu, but type b is the one we’ll talk about since it causes most of the severe infections. Type b, or Hib, is frequently found in the nose and throat and is transmitted through respiratory droplets, via coughs and sneezes of infected individuals. H. flu can be asymptomatic, meaning people can be carriers without cold symptoms. Asymptomatic carriers can transmit H. flu, especially to those who are not vaccinated.
Who is at risk for H. flu infection?
As adults, those who are immunocompromised or who have not been vaccinated are at greater risk. Sometimes booster shots for H. flu are recommended, such as in people who don’t have a spleen or people who have had a stem cell transplant. There is evidence that shows that Native American and Alaska Native populations have a higher incidence of H. flu, specifically with certain types of H. flu and despite widespread immunization. Researchers aren’t completely sure why this is the case, though some researchers think there might be variations in immune responses that cause the differences.
What are the risks of H. flu infection?
Hib can cause a number of serious diseases, including:
- Meningitis: an infection of the membranes that surround the brain and spinal cord. Before vaccines were available, this was the most common outcome of severe Hib. According to the CDC, meningitis accounted for 50-65% of severe Hib cases. The fatality rate was between 3 and 6%. Even with treatment, people who get meningitis can have neurological problems and long-term cognitive problems.Before vaccination campaigns, approximately 4.84 out of 100,000 children infected with Hib developed meningitis.
- Epiglottitis: an infection of the part of the throat that protects the larynx (commonly called the voice box) when you swallow. Swelling of this part of the throat can cause life-threatening obstruction of the airway, especially in children.
- Pneumonia: an infection of the lungs that can make it difficult to breathe.
- Septic arthritis: an infection of joints that can cause pain, swelling, and limited mobility. In some cases, septic arthritis can be deadly.
How do you prevent H. flu?
Hib is preventable via vaccines. The AAP recommends that children be vaccinated for Hib. The first dose is given at two months old, and the vaccine series is completed between 12 -15 months old. Before the vaccine for infants was introduced in 1990, around 20,000 young children per year became severely sick when infected with Hib and 1,000 of them died in the United States (1 of 20). Before the Hib vaccine, Hib was the leading cause of bacterial meningitis in children under 5. Overall, severe cases of Hib have decreased by more than 99% since vaccines have been introduced.
Overall, H. flu causes a wide variety of diseases, from meningitis to ear infections. H. flu infections can also be deadly. The type b variant of H. flu causes the most severe disease and can be prevented by a childhood vaccine.
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