What is Hib?
Haemophilus influenzae type B (Hib) is a bacterium that causes serious disease in young children throughout the world.
Hib causes one-third to one-half of all cases of bacterial meningitis. Bacterial meningitis is deadly unless treated immediately with the correct antibiotics. Even with proper treatment, 3-25% of affected children may die. 15-35% of children who survive Hib meningitis are left with permanent disabilities.
It also accounts for up to one-third of all cases of severe pneumonia which can also be deadly, especially for young children. Hib can also cause infections of the blood, joints, bones, throat, soft tissues and the covering of the heart.
Hib bacteria live in the nose and throat area. Like Measles virus, Hib bacteria are passed from child-to-child in droplets of saliva when an infected child coughs or sneezes or when children share toys and other objects they have put in their mouths.
Children often carry the Hib bacteria without showing any signs or symptoms.
In spite of its name, Hib does not a cause of influenza (or “flu”) or the common cold.
Who is most at risk for getting Hib disease?
Hib disease is most common in children under five years old. Children between the ages of four months and 12 months are most at risk. For that reason it is important to immunise the children and prevent disease very early in life.
At birth, antibodies from the mother sufficiently protect most infants. But when the child reaches two or three months of age, the level of maternal antibodies falls, and the risk of Hib infection increases.
By age of five years, children usually develop their own immunity against Hib. The disease is rare after the age of five.
Can diseases caused by Hib be treated?
Treatment for Hib disease is not always effective because some strains of Hib may be resistant to antibiotics. Antibiotic resistance is a serious problem and is increasing every day. Hib immunisation is more effective and less costly than treatment.
How effective is Hib vaccine?
Hib vaccine is highly effective. Complete vaccination with Hib vaccine (three doses of vaccine) reduces the risk of Hib disease in young children by more than 90%.
Hib vaccine does not protect against diseases caused by other germs. Even after complete vaccination with Hib, a child may still get other types of pneumonia, meningitis or viral infections, such as the flu.
Are there any contraindications to Hib vaccination?
No. Children over six weeks of age can be given Hib vaccine safely. Monovalent Hib vaccine (vaccine against Hib only) can safely be given to children, teenagers, or adults. But combination vaccines that include DPT vaccine should only be given to children over six weeks of age and under five years of age. DPT vaccine is not effective for children under six weeks of age and the “P” component of DPT (pertussis vaccine) can cause adverse reactions in children over the age of five, teenagers, and adults.
Pentavalent Hib vaccine includes (Hib+DPT+ Hepatitis-B) protects against five diseases (Hib disease, Diphtheria, Pertussis, Tetanus and Hepatitis-B).
Children should be immunised on schedule, even if they have a mild cold or fever, mild respiratory infection, etc. These are not contraindications to giving Hib vaccine.
What if a dose is missed?
To guarantee long-term protection, all three doses of pentavalent vaccine should be given at 6 weeks, 10 weeks and 14 weeks. If a child misses the date for vaccination, the child can be given the dose as soon as possible. There is no need to re-start the vaccination schedule.
Can an extra dose of Hib vaccine hurt the child?
An extra dose of Hib vaccine given after the last scheduled dose does not hurt children, but also does not increase the effectiveness of the immunisation.
What are the side effects of Hib vaccine?
Millions of doses of Hib vaccines have been given to children around the world. But there have never been any reports of serious reactions to Hib vaccine. However, if a child seems to have had a severe reaction to the vaccine, he or she should be given immediate medical attention.
Only 25% of children receiving Hib vaccine develop mild redness, swelling and soreness at the injection site. This will go away within 1-3 days, and is not serious. Parents may want to give the child paracetamol to treat these symptoms.
It is rare for a child to have a fever after being vaccinated only against Hib. However, infants vaccinated with pentavalent vaccine may have fever, probably because of the DPT.
Children older than five years, teenagers, and adults should not be given DPT vaccine, or any combination vaccine containing DPT, because there is a higher risk of adverse reactions for those age groups.
What is the Pentavalent vaccine?
The pentavalent vaccine combines five different vaccines in one injection to protect against five diseases: Haemophilus influenzae type B (Hib) disease, Diphtheria, Pertussis, Tetanus and Hepatitis-B.
Children immunised with the 5-in-1 vaccine do not need anymore to be vaccinated separately with the DPT vaccine or the Hepatitis B vaccine as he will get those in the same injection.
Who should get penta-valent vaccine?
All children between six weeks and five years of age should receive three doses of pentavalent vaccine with an interval of at least four weeks between the doses. However children who have already started immunisation with DPT and Hepatitis-B will complete their vaccination with DPT and Hepatitis-B. They will not get pentavalent vaccine.
Vaccination with pentavalent must be completed within two years of age if the child starts before 1 year of age.
Children under six weeks of age, over five years, teenagers and adults should never be given pentavalent vaccine because of the DPT component.
Source: The Daily Star, January 17, 2008