What is a Subunit Vaccine?

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  • Written By: Mary McMahon
  • Edited By: Kristen Osborne
  • Last Modified Date: 24 September 2019
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A subunit vaccine is a vaccine that contains isolated proteins from a virus, but lacks viral nucleic acid. These vaccines expose the body to antigens so it can learn to recognize them without exposing the body to the risk of viral replication and subsequent infection. Several influenza vaccines are available in the form of subunit vaccines and numerous drug companies are working on applying the technology to the development of other types of vaccines as well. The primary advantage of using a subunit vaccine is that it is very safe, even in people with compromised immune systems.

To make subunit vaccines, pharmaceutical companies strip away everything but the proteins associated with specific and unique antigens. With the use of genetic engineering, organisms can be manipulated so they will express these proteins in large amounts for vaccine production. The subunit vaccine is not virulent because it does not contain the genetic material from the virus, only the proteins on the exterior of the virus.

When these vaccines are administered, the immune system learns to recognize the antigens and develops specific antibodies. This ensures that when the virus enters the body, the immune system will identify it and target it for destruction before it has an opportunity to begin replicating and causing disease. Because the material in the subunit vaccine is not capable of replicating, the risk of adverse reactions is very low and the vaccines are safe for use in people with poor immune systems.


One problem with the subunit vaccine production technique is that sometimes isolating the proteins denatures them, causing them to take on a different shape. The immune system develops antibodies to the denatured proteins, but will not recognize the viral proteins in situ on the coating of a virus. Some researchers have addressed this issue by making recombinant subunit vaccines, where proteins from a dangerous virus are combined with a benign virus for delivery in the form of a vaccine. This prevents the proteins from denaturing and teaches the immune system to recognize the proteins on the surface of a virus.

Isolating specific proteins provides opportunities for vaccinating against multiple strains of a virus, an important characteristic for flu vaccines. Research on vaccines for the human immunodeficiency virus has also involved the development of subunit vaccines that could use specific proteins to teach the body to recognize and eliminate HIV without exposing people to the risk of viral replication and HIV infection.


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Post 4

The pertussis vaccine is also a subunit vaccine. You can't get measles from the MMR vaccine although very, very rarely children can develop a viral meningitis from it.

Generally speaking, there is almost no chance of a healthy person developing a disease as a result of a live, attenuated virus vaccination. If you are HIV+, are pregnant, or suffer from a immunological disorder then you should be concerned about live virus vaccines.

When people talk about live virus vaccines, these are versions of the pathogenic virus that have been changed or allowed to mutate so that they are not capable of causing the original disease anymore.

If a vaccine is made from killed virus/bacteria, you cannot contract a disease from the vaccine.

Post 3

@robbie21 - I don't think there's a choice; most vaccines come in only one form (an exception would be flu, which is available either live or dead, nasal or injected). The subunit vaccine examples I know about are Hep B and HPV (genital wart/cervical cancer), but it's an area where a lot of new research is being done.

You know, I tried and tried to find out whether you can get measles from the MMR shot, and got nothing. I know that one's a live virus, so you would think if you could anything from the vaccine, it would be that. Live makes for a nice strong immune response if you're healthy (not such a good idea if you're not). Maybe someone else will help us out.

Post 2

Subunit vaccines sound great for people who are worried about vaccine safety, not just people with compromised immune systems. Are there any subunit vaccines that are widely available?

The last sentence of the article worried me a little. With "regular" vaccines--the ones made with either killed or live but weakened viruses--is there a risk that you'll get the disease? Can you get, say, measles from the vaccine?

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