This is usually true, but the opposite can happen if it's mutating in a host population that is vaccinated against symptoms, but can still contract and spread the virus. In this case the virus is ls likely to become more deadly. This scenario has happened with Mareks disease in Chickens. This is their plan (conjecture). The virulence of Covid will be increased. If the Leaky vaccine doesn't result in this effect, they will release another strain with it's lethality increased in the lab. Vaccinated people will be safe, but will still contract and spread it. The unvaccinated will die. The world will be held hostage, dependent on the vaccine which requires renewal doses, and the whims of those who control it.
Meriks: https://www.pbs.org/newshour/science/tthis-chicken-vaccine-makes-virus-dangerous
This is usually true, but the opposite can happen if it's mutating in a host population that is vaccinated against symptoms, but can still contract and spread the virus. In this case the virus is ls likely to become more deadly. This scenario has happened with Mareks disease in Chickens. This is their plan (conjecture). The virulence of Covid will be increased. If the Leaky vaccine doesn't result in this effect, they will release another strain with it's lethality increased in the lab. Vaccinated people will be safe, but will still contract and spread it. The unvaccinated will die. The world will be held hostage, dependent on the vaccine which requires renewal doses, and the whims of those who control it. Meriks: https://www.pbs.org/newshour/science/tthis-chicken-vaccine-makes-virus-dangerous
The Spanish Flu fit that pattern. The second wave was far more deadly than the first.