Wikipedia defines herd immunity in the following way: “is a form of indirect protection from infectious disease that can occur with some diseases when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby reducing the likelihood of infection for individuals who lack immunity”.
The picture above really sums it up. The guy in red has COVID, but he is surrounded by people that are immune. Thus, the disease is walled off by the herd. COVID cannot spread anymore because everyone around the infected person is immune.
The best way to reach herd immunity is to come into contact with people who have had COVID and are now healed. Although that person is healed, he is still coughing up dead virus. Dead virus is the definition of a vaccine. Nature self regulates like in the case of predator and prey. In this case, nature generates a deadly parasite but nature also has a mechanism to keep that parasite under control.
Why is this important? Lockdowns are the worst way to achieve herd immunity. You are more likely to get the virus indoors. Plus, when you are locked down, those who are healed cannot spread the natural vaccine. Therefore, in an open society, mass vaccinations are not necessary. I know my government knows this – no one is that stupid.