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

At its very simplest, viral vaccines work by teaching your body to recognize viruses from a distance, basically how to recognize their shape and outline. Your immune system is basically just on the prowl comparing the outline and shape of every thing it sees to a list it keeps in it’s pocket, like an old timey Police Officer looking for outlaws.

Chicken Pox, measles, polio, etc., those viruses haven’t really changed much since they first started infecting people. Nothing magic or special, it’s just that those viruses don’t spend their Level Up XP on changing their shape. So once they are added to your immune system’s list, they can be spotted pretty much forever. It is worth nothing though that those lists are essentially get photocopied over time and after 20 or 30 years can be pretty rough looking so it might be smart to make the list from scratch again – to get a new vaccination.

The ‘corona viruses’ though, the family of viruses that include SARS 1, SARS 2 (COVID), and the Flu absolutely *do* spend their level up XP on changing their shape. In fact that’s the only thing they spend their XP on. Just change shape change shape change shape with every single level. You might have noticed we keep talking about new COVID strains and subtypes and mutations? Corona viruses are like hermit crabs, constantly changing their shells. So pretty much impossible to learn to fight only by looking at their silhouette and shadow.

What we do with the Flu, which is very seasonal, is see what it “looks like” in the Northern Hemisphere, get like 6 or 10 of those general shapes and make them into a cocktail to give to the Southern Hemisphere in their winter 6 Months later. Then we see what’s up in the Southern Hemisphere and repeat it with the northern 6 Months later. This is why we sometimes miss and end up with bad flu years when it changes into something we didn’t see coming.

It’ll probably be like that with COVID, with use using a cocktail of “we think it looks like this” sketches and shifting it up 2x per year as new strains emerge.