How does a polysaccharide vaccine work?

Polysaccharide vaccines stimulate B-cell responses, thereby resulting in type-specific antibody production that enhances ingestion and killing of the pathogens by phagocytes. The antigens, however, are T-cell independent and therefore do not result in long-lasting immunity.

What is the difference between conjugate and polysaccharide vaccine?

In the polysaccharide vaccine, only the sugar part of the bacteria, the capsule, is included as the antigen to stimulate the immune response. “In the conjugate vaccine, it's actually the sugar joined to the carrier protein,” says Associate Professor Kristine Macartney.