why can viruses like chicken pox, measles, polio, shingles be handled with a single, or pair, of vaccinations, but flu and COVID require repeat vaccinations.

Question

Hopefully title covers the question. All of the above are viruses and I understand that the latter two mutate. Wouldn’t the first ones I listed also mutate over time? Is the difference more a function of type of vaccines, or the viruses themselves? Why does this difference in preventative care exist? I think even the new RSV vaccine is a single does. Looking forward to understanding this better. TIA

In: 16

Answer 1

You got it right, some viruses simply mutate more rapidly and have different variants, while others don’t. It depends on their preferred replication mechanism, which allows for different rates of mutation.

Coronavirus for example mutates incredibly fast, so we need to keep the vaccines updates, while Shingles is really stable, so one vaccine is enough.

That said, there’s another factor at play here, which is immune memory. Some viruses and bacteria elicit a greater immine response, and the protection lasts for a long time, sometimes for a lifetime.

Other microorganism instead generate a weaker immune response, and after some time the immune system needs to “see” the virus/bacteria again to relearn how to deal with it.