Haemophilus influenza b (Hib) vaccine

What is Haemophilus influenza b (Hib)?

Haemophilus influenza type b is a bacterium that causes a host of infections. These infections range from mild to severe and mostly affect children. There are 6 different types of H. influenzae bacterium (from a to f), out of which Hib is the most known type. This bacterium normally lives in the nose and throat and is harmless; however, sometimes they can move to other “germ-free” parts of the body and cause serious infection. 

Signs and symptoms of Hib disease vary depending on which part of the body is affected.

How is Haemophilus influenza b spread?

  1. influenzae, including Hib, spreads from person-to-person through saliva. When a person carrying the bacteria in their nose or throat coughs or sneezes, the chances of the bacterium being spread to other people increase. Most of the time, H. influenzae are spread by people who have the bacteria in their noses and throats but are not ill or do not have any symptoms (asymptomatic)2.

Sometimes H. influenzae spreads from other people who have been in close contact with a person already infected with H. influenzae disease. In some cases, people in close contact with that person should receive antibiotics (medicines that kill bacteria in the body) to prevent them from getting the disease2.

Haemophilus influenzae type b be can be prevented by vaccination1.

Where is Haemophilus influenza b found4?

Hib disease occurs mostly in babies and children younger than five years old. Other risk factors for Hib disease include a large household size, child care attendance, low socioeconomic status, low parental education levels, and school-aged siblings. Gender is also a factor as males are at a higher risk of getting the disease than females.

What is a Haemophilus influenza b Vaccine5?

The Haemophilus influenzae type b (Hib) vaccine is available in different types. Hib vaccine is given to infants as young as 6 weeks old.

Hib vaccine may be given as a part of combination vaccine. Three combination vaccines are available. One of the three combination vaccines, a Meningococcal Groups C and Y and Haemophilus b tetanus toxoid conjugate vaccine is used for infants and children aged 6 weeks through 18 months.

None of the Hib vaccines protect against any other types of Haemophilus infection other than type b. It also does not protect against meningitis caused by any other bacteria.

Who should get vaccinated?

The Centre for Disease Control recommends the following groups of people to get Hib vaccination compulsorily6

  • All children younger than 5 years old
  • Some people at increased risk for invasive Hib
  • Unvaccinated older children and adults with certain medical conditions (eg, people suffering from HIV, sickle cell anemia, people receiving chemotherapy or radiation therapy)

Children over 5 years old and adults usually do not need Hib vaccine and Hib vaccine should not be given to infants younger than 6 weeks of age.

How effective is the vaccine?

Hib vaccine can prevent Hib disease.  Studies show that nearly all (between 93 and 100 out of 100) children are protected from getting Hib disease after receiving the 1st 2 or 3 doses of Hib vaccine, as per the vaccination schedule8. Many more children would get Hib disease if the vaccination is stopped. Therefore, this vaccine comes under the “essential vaccines” category.

Are there any side effects8?

As with any other medicine or vaccine, Hib vaccination can cause mild to moderate effects which will go away on its own. Most people who get Hib vaccine do not have any problems with it. Most common mild problems with Hib vaccines are –

  • Fever
  • Redness or rash at site of the shot

Serious reactions with Hib vaccines are also possible but are quite rare.

What if a dose is missed?

If you miss a dose of Hib vaccine, call your doctor immediately. Every child under the age of 5 years needs at least one dose of Hib vaccine to stay protected.


  1. http://www.who.int/topics/haemophilus_influenzae/en/
  2. https://www.cdc.gov/hi-disease/about/causes-transmission.html
  3. https://www.cdc.gov/hi-disease/about/types-infection.html
  4. http://www.nvic.org/vaccines-and-diseases/HIB/hib-highest-risk.aspx
  5. CDC.gov. Haemophilus Influenzae Type B. The Pink Book. No Date. Online. http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/hib.pdf. (Accessed June 2012)
  6. https://www.cdc.gov/vaccines/vpd/hib/public/index.html
  7. https://www.cdc.gov/vaccines/hcp/vis/vis-statements/hib.html
  8. https://www.cdc.gov/vaccines/vpd/hib/public/index.html