The HIB Vaccine

The HIB Vaccine uses the basics of vaccines to prevent catching the HIB (Haemophilus influenzae type b)

Vaccine Basics || Click on the next slde to learn more

Perfecting the Vaccine

Hib bacteria have a protective polysaccharide capsule (a sugar coating) called polyribosylribitol phosphate (PRP).
Our immune system has a hard time recognizing polysaccharides alone, especially in infants and young children, because:
Polysaccharides trigger a T-cell independent immune response.
This type of response is weak and does not create strong memory.
So, a vaccine made of just the Hib polysaccharide would not protect young children effectively.

1. The Problem: HIB VACCINE

2. The Solution: Conjugation

Scientists attach (conjugate) the Hib polysaccharide to a protein carrier—in this case, tetanus toxoid (a harmless form of the tetanus toxin).
Why tetanus toxoid?
- Proteins are recognized by T-helper cells, which can amplify the immune response.
- Using tetanus toxoid is safe and already known to be very effective at stimulating immunity.

3. How the Immune System Responds

Recognition: Immune cells recognize the conjugate vaccine.
The B cells bind the Hib polysaccharide.
The protein part (tetanus toxoid) is presented to T-helper cells.
Activation: T-helper cells provide signals that tell B cells to:
Make antibodies against the Hib polysaccharide.
Create memory B cells.
Protection: The body now has:
Antibodies that can attach to Hib bacteria if encountered in the future.
Immunological memory—so the immune system responds faster and stronger on actual exposure.

Now that we injected our vaccine into out body, let's see what's happening inside of it and how the vaccine is created as well!