How long does the vaccinations effect last?

How long does the vaccinations effect last?

A few months after the second dose, protection against symptomatic covid 19 disease decreases to a greater or lesser extent depending on the vaccine. The percentages do not accurately represent the effectiveness of the vaccines; they also depend on possible differences in the behaviour of vaccinated and unvaccinated people. How long does the vaccinations effect of different vaccines last? What do the study results show?

How long does the vaccinations effect last?