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

A disease evades vaccination by changing into different variations of itself. Diseases mutate based on two factors: how many people have the disease and how unstable is the disease?

COVID spreads around a lot more than chicken pox. That gives it more opportunities to change into a variant.

COVID is also much less stable than many other diseases, meaning it can change a lot faster.

That combination means COVID regularly changes enough to evade vaccines.

However, it’s important to know that even an old, out-of-date vaccine gives you better protection than being unvaccinated. The new vaccine is an attempt to update your defenses against the newest variants.