To be honest, I don't think group immunity is a reliable thing. On the one hand, the virus will mutate, on the other hand, there are too many uncertain factors in group immunity. In this case, although it is possible to achieve group immunity in theory, it is not the best way to prevent epidemic in real life.

First, the virus will mutate.

To some extent, group immunity can't stop the mutated virus, so in this respect, group immunity is not reliable. This is because although human beings are immune to the virus, with the variation of the virus, human beings may not necessarily produce new immunity to deal with the mutated virus. In other words, if the speed of human immunization can't keep up with the speed of virus mutation, it is almost impossible to achieve group immunization. I believe most people know that COVID-19 will mutate. After all, since the outbreak, people have found several mutant viruses, such as Delta strain and Omicron strain. So when the virus is still mutating, group immunity is not a good choice.

Second, there are too many uncertain factors in group immunity.

In theory, group immunity can be achieved, but due to the influence of various uncertain factors, the effect of group immunity is likely to be greatly reduced or even counterproductive, so from this perspective, group immunity is unreliable. We should know that uncertain factors have a great influence on group immunity, and any adverse influence on group immunity may lead to the failure of group immunity, such as human beings can not produce enough immunity against virus, or the sequelae after infection with virus are too large. Therefore, it can be said that under the influence of uncertain factors, group immunity is not a good means to fight the epidemic.

To sum up, because the virus will mutate and there are too many uncertain factors in group immunity, it seems to me that group immunity is actually not reliable.