HiB (Haemophilus Influenzae Type B) Vaccine

Once a vaccine enters your body, the body reacts exactly in the same way as it does when the same organism infects you. But the difference is that the organism in the vaccine is not capable of causing damage to your body and the quantity of germ in the vaccine is very low to produce only a mild reaction.

Now, after vaccination, as the body is already exposed to the organism, the immune system is sensitised and knows what to do if the same germ attacks again. Hence when later in life, you get exposed to this germ, the specific immune system (the memory T cells in the immune system does the job of remembering that germ) is activated and the germs are killed even before it causes harm to the body.

If there were no vaccines given by the time the immune system figures out what to do, the damage would be done which might be life-threatening. Then why do we have side effects after vaccination in some cases? That is because, as mentioned above the body tends to react and this results in side effects. The fever is an increase in body temperature because the body is all heating up to fight the organism. It is not what the germ is doing to you.

What is the HiB Vaccine?

HiB vaccine is an injection that is given as a preventive measure for Haemophilus influenzae type B infections. It contains a part of the capsule of dead bacteria H. influenzae. There are six types (designated a–f) of H. influenzae that cause different diseases. The HiB vaccine is specifically against the type b and does not extend protection against the other types. H. influenzae type b vaccine is a conjugated vaccine.

Who Should Get HiB Vaccine?

HiB vaccine is recommended for all the children below 5 years of age. It is necessary to complete all the doses for it to be effective.

Older children who were not vaccinated earlier and high-risk adults, even if they were vaccinated earlier, are eligible in special circumstances.

Recommended HiB Vaccine Schedule

HiB vaccine is available as monovalent vaccine or in combination with other vaccines.

Recommended Doses:

The recommended schedule is two or three doses depending on which type of vaccine is given starting at the age of 2 months. Each dose is given 8 weeks apart. After these primary HiB vaccine dose, a booster dose is recommended at the age of 12-15 months and there should be a gap of minimum 8 weeks since the last dose.

Recommended Ages:

Here’s how the doses are administered:

• First Dose: 2 months of age
• Second Dose: 4 months of age
• Third Dose: 6 months of age (if needed)
• Final/Booster Dose: 12-15 months of age

The Government of India has recommended use of pentavalent vaccine (LPV) – which is a combination vaccine of HiB with 4 others: DPT and Hep B. in 3 doses at 6 weeks, 10 weeks and 14 weeks of age. Booster dose of HiB at 12-15 months is recommended by the IAP (Indian Association of Paediatrics) but not included in the universal immunisation schedule of Government of India.

What Are Benefits of the HiB Vaccine?

HiB disease is a serious, invasive and life-threatening disease. The germ spreads very easily through contact with the droplets of secretions from an infected person. This means that simply breathing next to an infected person can cause infection to you without your knowledge. Simply carrying around the germ in the nose and throat will not make you sick unless it reaches the lungs and the blood. This also means that the person next to you might be completely healthy and yet one sneeze or cough can be infective. HiB vaccine prevents an invasive infection despite being infected. Since the use of HiB vaccine began, there has been a 99% decrease in the number of cases. In the United States, before HiB vaccine, about 20,000 children below 5 years got HiB disease each year, out of which 3% – 6% of them died.

Is It a Must to Give Child HiB Vaccine?

All children below 5 years of age are at a very high risk of being infected with HiB. This deadly bacteria is known to cause meningitis (inflammation of the membranes covering the brain and spinal chord) that can lead to brain damage and deafness. It also causes pneumonia, epiglottitis (swelling in the throat that makes breathing difficult), infections of the blood, joints, bones, and heart and death. So undoubtedly, prevention is better than cure.

Who Should Avoid HiB Vaccine?

• HiB vaccine is not to be given to a baby less than 6 weeks of age.
• An otherwise healthy adult does not require HiB vaccine.
• If there has been a severe allergic reaction to the previous dose of vaccine or a component of the vaccine, please do inform your doctor. It could be life-threatening.
• If the child is not feeling well on the day of scheduled vaccination, tell your doctor. Mild illness is fine. But moderate to severe illness is a contraindication to the vaccine. Wait till the child recovers.
• The HiB vaccine falls under category C for pregnant women; use with caution if benefits outweigh risks.

What Can Be The Side Effects of HiB Vaccine?

Any vaccination can cause mild side effects and the same holds true with HiB vaccine. The doctor will evaluate the HiB vaccine risks against benefits and take a call before administering. Serious side effects are rare but possible. Majority cases do not experience any side effect at all. Mild side effects include mild fever, pain, redness and swelling at the injection site.

The child may become irritable and drowsy. Allergic reaction can be mild or serious enough to need an emergency intervention. Such severe reactions are as rare as 1 in million doses. Older children or adults may feel dizzy or have headache, vomiting and diarrhoea.

What Precautions Should You Take?

Avoid getting the shot when the child not feeling well. Maintain your child’s immunisation record and update it each time. Inform the school or the childcare about the immunisation and ask them to report if any red flag signs are seen. Look for the red flag signs and immediately consult your doctor.

When Should You Call Healthcare Provider?

Any of the following, particularly within first 3-4 days, warrants an immediate visit to your health care provider:

• high fever
• swelling of the face or mouth
• trouble breathing
• hives
• convulsions or seizures
• very pale colour
• drowsiness
• weakness
• fast heartbeat
• other serious problems

FAQs

1. After receiving HiB vaccine, will my child get meningitis as well?

There is a remote possibility especially if the doses were not completed. But an invasive HiB infection in a completely vaccinated child is not common. Also, there is a possibility of meningitis from causes other than HiB.

2. What if my child missed a dose of HiB vaccine?

Here is the catchup schedule if the first dose was delayed by >1 month

• First dose at age 7 – 11 months: a second dose 4 weeks later, skip 3rd dose and give a booster dose as usual.
• First dose at age 12 -14 months: a second dose after 8 weeks. No further doses are indicated.
• First dose at age 15 – 59 months: no further doses are indicated.
• Children aged ≥5 years not vaccinated earlier are not high-risk and do not require catchup vaccination.

3. Can HiB vaccine be given with other vaccines?

Yes. Combination vaccines are available where you can have the vaccine injected along with others.

Conclusion

HiB vaccine is essential for protecting against life-threatening infections for children and adults. Make sure you keep your child up to date with the recommended immunisation programme to ensure that he/she stays healthy.