>preventing a non-zero number of infections and transmissions
You could argue it prevented transmissions, but given the vast majority of people everywhere have been infected, it's hard to argue the covid vaccines prevent infection, no? They only delay it.
Every exposure to COVID results in one of two possible outcomes: infection, or no infection. The COVID vaccines without a doubt increase the frequency of the second outcome and decrease the first, although their efficacy by this metric has been waning for over a year (they still seem superb at preventing serious illness and death). "Infections" doesn't mean "people who have ever been infected," which at this point is approaching 100% of the human population, it means "infections." The COVID vaccines prevent infections.
You think infection only happens once? People are racking up 3rd, 4th, 5th etc. infections now. Each one is another chance to create mutations. It will not stop until we stop transmission.
The more vaccinated/up to date boosted the population then the less chance for overall spread and transmission, leading to less mutations.
You could argue it prevented transmissions, but given the vast majority of people everywhere have been infected, it's hard to argue the covid vaccines prevent infection, no? They only delay it.