You can never know anything for sure. This is why science, medicine and drug approvals are all about probabilities and calculated risks. If everyone suddenly dropped dead 10 years after taking a drug that was approved in 2015 there is no way we could know that right now. But we know it's very, very unlikely, so we accept that risk.

With vaccines we know from decades of experience that severe side effects tend to occur very shortly (days or maybe weeks) after the injection. So this is why vaccine trials observe participants for weeks or months, not years, before concluding that the vaccine is safe. Of course this doesn't guarantee that the Covid vaccine don't happen to be an exception. But if that was the approach we took then we would never be able to approve anything, and never get the benefits we know for sure it brings.

mRNA has a short life span. It merely tricks the body into producing the spike protein. It breaks down in the body fairly rapidly. What long term effects would you anticipate from this?

There is a good chance for long term effects from covid. Completely the opposite for the vaccine.

People need to remember that we're not taking the vaccine for fun, we're taking it because COVID is out there and we know for certain that it has some lethal side effects as well as non-lethal side effects and possibly other long-term side effects that we don't yet know about. We weigh that risk against the risk that there might be some long-term side effects of the vaccine. To the best of our knowledge, the risks posed by COVID are more dire than those posed by the vaccines and we basically have to choose one.

> Given this statement is not qualified for timescale

Keep in mind that we also don't know the long-term effects of COVID-19. It's possible that people who were infected with mild cases drop dead 1 year and 6 months after the infection. The disease hasn't been around that long, so we simply don't know.