Why have I been reinfected with Covid-19 despite being vaccinated?

The Omicron BA.5 viral subvariant is currently the dominant SARS-CoV-2 strain worldwide; however, it may soon be overtaken by other Omicron subvariants. — SAMUEL ONG/The Star

There are some vaccinations for certain diseases that will completely prevent you from getting the disease, such as smallpox and measles.

That is because those viruses don’t mutate a lot.