How Do Vaccines Work? Dr Norman Swan
Vaccines work by, essentially, training our immune system in a safe way, in this case, with COVID 19, a virus.
So the natural infection is a live virus and that live virus teaches your immune system and you will become immune for awhile as a result of that. But the trouble is, with the live virus, you get disease. So the idea with any vaccine is to safely give you enough of the virus or the virus in a certain form, that will induce an immune response without getting disease.
So with measles, for example, they use a live form of the measles virus, but it’s been neutered to the extent that it cannot cause disease. It can get into the body, generate an immune response, a very good immune response, but not cause measles. HPV immunisation against cervical cancer, that immunises you against the human papilloma virus, stops it getting into cervical cells or cells in your mouth and causing cancer. So that’s what vaccines do, but they do it in different ways.
Sometimes it’s the whole virus. Sometimes it’s a live virus. Sometimes it’s an activated virus like influenza or one of the COVID-19 vaccines. And sometimes it’s a genetically engineered protein that they inject directly into your body that generates the immune response and that’s what happens with COVID-19.
Unfortunately with HIV, we have yet to be able to produce a vaccine for HIV and that’s because it’s a very complicated virus and it changes its spots all the time. And it’s very hard to find the spot on HIV, which is the right way to target for the immune system. Because the HIV uses the immune system, itself, to attack our body and hides in the immune system. Very difficult virus to immunise against.
Dr Norman Swan, Physician and Journalist
Last Reviewed: 16/01/2021