Hib FAQs

Download Hib Catch up campaign booklet by clicking on Hib Catch up campaign booklet
Download Hib routine booster leaflet by clicking on 

This document should be read in conjunction with the summary of product characteristics (SPC) issued by each vaccine manufacturer

What is Haemophilus influenzae?
Are there different types of Haemophilus influenzae?
What is Haemophilus influenzae type b?
How is Hib transmitted?
Who is most at risk of Hib infection?
When was the Hib Vaccine introduced? 
Is a Hib Booster necessary? 
What about children born between 21st May 2005 and 17th September 2005?
What if a child has already received a dose of Hib or 5-in-1 after 12 months of age?
What is in the Hib vaccine?
Does the Hib vaccine contain thiomersal (mercury)?
How safe and effective is the Hib vaccine?
Are there side effects from the Hib vaccine?
Are there any reasons why the Hib vaccine should not be given?
References

What is Haemophilus influenzae?

Back to top

Are there different types of Haemophilus influenzae?

Back to top

There are a number of strains of H. influenzae. Strains are classified as those with capsules (capsular types) and those without capsules (non-encapsulated types). Six capsular types (a-f) are recognized. In the prevaccine era, type b was the most commonly reported strain. The non-encapsulated strains cause mucosal infection (such as middle ear infections, called "otitis media") but rarely lead to serious invasive disease.

What is Haemophilus influenzae type b?

Back to top

H. influenzae type b (also known as "Hib") is just one of six H. influenzae types. Before a vaccine was available to prevent H. influenzae type b disease, Hib accounted for approximately 80-95% of all strains that caused invasive illness.

You may find the following table useful when explaining the disease to parents.

How is Hib transmitted?

Back to top

Hib lives in the nose and throat of humans and is transmitted from person to person through respiratory droplets, or contact with respiratory secretions. The bacteria may be carried around in the nose and throat for a short while or for several months without causing symptoms ("asymptomatic carrier"). In some individuals (particularly those most at risk) Hib will invade the body causing invasive disease (e.g. meningitis, septicaemia).

Who is most at risk of Hib infection?

Before Hib vaccine was introduced children less than 4 years of age were most at risk from Hib disease. Over 2,000 cases were in children under 4 years of age and the age group most at risk was infants of 10 – 11 months.

Other individuals at risk of Hib infection are individuals with a malfunctioning spleen, or asplenia, irrespective of how old they are (e.g. sickle cell disease, HIV, or other immunodeficiency).

When was the Hib Vaccine introduced?

Back to top

Since 1992, Hib vaccine has been offered to all children as part of the routine childhood vaccination programme in Ireland. Hib vaccine is part of the “five-in-one” vaccine (DTaP-IPV-Hib) and is given at 2, 4 and 6 months of age.

Is a Hib booster necessary?

Back to top

After 12 months of age the risk of Hib disease steadily declines but children aged 1-4 years continue to be at risk. It now appears that the immunity from the 2, 4 and 6 months immunisations wanes and does not give sufficient protection to some children in this age group.

In response to this information, the National Immunisation Advisory Committee (NIAC) recommended that a Hib booster vaccine at 12 months of age be included in the routine childhood immunisation programme.

From 18th September 2006 all children reaching 12 months of age should be given a Hib booster at the same time as MMR vaccine.

The introduction of a routine Hib booster follows the recent for children born between and 2nd November 2001 and 20th May 2005.

What about children born between 21st May 2005 and 17th September 2005?

Back to top

Children born between 21st May 2005 and 17th September 2005 should be given a Hib booster

What if a child has already received a dose of Hib or 5-in-1 after 12 months of age?

Back to top

Any child who has received one dose of Hib or 5-in-1 after the age of 12 months has adequate protection and does not need a Hib booster vaccine.

What is in the Hib vaccine?

Back to top

The Hib vaccine is made from a purified component of the sugar coat of the bacteria. The sugar is then joined to a protein to form what is called a conjugate vaccine. It is not a live vaccine and therefore cannot cause Hib disease.

Does the Hib vaccine contain thiomersal (mercury)?

Back to top

No the Hib vaccine does not contain thiomersal.

How safe and effective is the Hib vaccine?

Back to top

The Hib immunisation programme introduced in October 1992 has had a striking impact in reducing the number of invasive Hib infection in children. The number fell by 90% and cases of Hib disease are now rare. Hib vaccine has been proven to be one of the safest vaccines available. Over 20 million doses had been used worldwide and no serious adverse reactions had been reported. Since 1996 approximately 450,000 children have been vaccinated against Hib disease in Ireland and over that period just 39 cases acquired the disease despite being fully vaccinated.

A re there side effects from the Hib vaccine?

Back to top

Local: These include local redness, warmth or swelling at the injection site. Mild local reactions occur in about 20% of children.

General:Systemic reactions are uncommon and include fever, irritability, headache, vomiting, diarrhoea and rashes. Seizures have rarely been reported.

Any adverse vaccine reactions (ADRs) should be reported to the Irish Medicines Board via the yellow report card (available on www.imb.ie).

Are there any reasons why the Hib vaccine should not be given?

Back to top

Contraindications:Previous anaphylactic reaction to any component of the vaccine.

Precautions: Immunisation should be deferred in any child with acute febrile illness until the illness has resolved.
Hib vaccine may be given to immunocompromised patients, but adequate antibody levels may not be reached.

References

Back to top

1. Immunisation Guidelines for Ireland. Immunisation Advisory Committee RCPI 2002. Available at www.ndsc.ie
2. Fact sheet Haemophilus influenzae type b (Hib) Immunisation Information NHS 2003
3. Hib New booster for children under 4. Immunisation Information NHS 2003
4. HPSC Fact sheet Haemophilus Influenzae type B (Hib) www.ndsc.ie
5. HPSC. Immunisation Uptake Report for Ireland. Quarter 1 2005 www.ndsc.ie
6. Heath PT, Booy R, Azzopardi HJ, Slack MP, Bowen-Morris J, Griffiths H, et al. Antibody Concentration and Clinical Protection After Hib Conjugate Vaccination in the United Kingdom. JAMA. 2000; 284:2334-2340
7. Trotter CL, McVernon J, Andrews NJ, Burrage M, Ramsay ME. Antibody to Haemophilus influenzae type b after routine and catch-up vaccination. Lancet. 2003; 361:1523-4.
8. Breukels MA, Spanjaard L, Sanders LA, Rijkers GT. Immunological characterization of conjugated Haemophilus influenzae type b vaccine failure in infants. Clin Infect Dis. 2001 Jun 15;32(12):1700-5. Epub 2001 May 16..
9. McVernon J, Trotter CL, Slack MP, Ramsay ME. Trends in Haemophilus influenzae type b infections in adults in England and Wales: surveillance study. BMJ. 2004; 329: 655–658.

Author: Dr Brenda Corcoran