Advantages & Disadvantages of Subunit Vaccines

While traditional vaccination technologies made use of living or dead pathogens (bacteria or viruses responsible for disease), advances in immunology have led to the development of alternative methods of immunisation. One of these is the subunit vaccine, a treatment which relies on specific parts of a pathogen’s structure to immunise against disease.

What are the advantages of subunit vaccines?

The major advantage of subunit vaccination is safety. Live vaccines pose a number of risks which are offset by the strong immunity they can provide with as little as a single dose, however as diseases become less prevalent, these risks become more of a concern as they are not necessarily warranted. Live vaccines can potentially revert, which means that they can undergo a change in their genetic material that would change them from a safe, harmless version of a pathogen into a virulent and dangerous one.

These vaccines also present a threat to men and women with health concerns. People who suffer from chronic illness or are immunocompromised, as well as pregnant women and the elderly can’t safely take live vaccinations, and so effective alternatives are needed.

Subunit vaccines circumvent both of these concerns as rather than a whole pathogen, specific fragments of a disease causing agent are used to stimulate the immune system. This is an extremely safe method of immunisation, and can be used on virtually everyone in need of vaccination regardless of health status.

What are the disadvantages of subunit vaccines?

Despite their safety and effectiveness, there are a number of key disadvantages to the use of subunit vaccinations. Unfortunately subunit vaccines are less successful at inducing long lasting immunity against disease. Live vaccines can confer immunity in one or two doses, whereas subunit vaccines will need to be administered repeatedly over specified periods of time to effectively immunise against a disease.

To increase their effectiveness, subunit vaccines will often need to be engineered alongside carriers to form what are called conjugate vaccines.

Subunit vaccines also need to be engineered to contain a number of different surface proteins unique to the disease in question. Some viruses and bacteria can contain a number of different structural proteins which identify them as pathogens, and preparing a vaccine with just one of these structures won’t be enough to provide effective immunity.

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