Not sure of what you meant but measles is really the anti example of a "natural" herd immunity. While most of the newborn were systematically vaccinated 20 years ago, the measles cases were slowing down wordwide (divided by four in ten years time) then some stupid antivaxx spread the idea vaccination was a worldwide conspiracy and didn't allow their children to have the vaccine.
Guess what : there is now an uprising of Measles in most of the countries (we have now more cases worldwide than 15 years ago).Measles was supposed to be eradicated in the UK and US, not any more if you look at 2018-19 figures.
That is for "natural herd immunity".
I made no mention of natural 'herd' immunity, where this exists is in local populations. I did suggest an example where local water sources hosts local strains of bacteria. The local population will have immunity, visitors will not, but I wouldn't call that a natural herd immunity. That is not Indo specific, I can think of many people that have had amoebic dysentery when visiting remote areas from tainted water. This is not that the water is inherently unsafe but that the bacteria in it are unfamiliar to the visitor's microbiome and their own flora are unable to contain the new bacteria. A natural immunity to a virus would be far more complex.
Herd immunity means that enough of the population are immune that the virus is essentially nullified. Measles is one where if you get enough of the population vaccinated, those that cannot be vaccinated are still safe. If enough people elect to not be vaccinated because a hack falsified data, herd immunity is lost because enough of the population is vulnerable, enough vectors become available that the virus can propagate.
The absurd thing is Wakefield never argued against vaccines, he was patenting his own measles vaccine to market once he'd discredited the MMR vaccine with his false data. But the antivax movement extrapolates his lies into the myth vaccines are bad. Living proof that you can lead a fool to data but you cannot make them think.
I'm unsure that SARS-COV-2 and its method of transmission can achieve the same thing. Yes, like the flu vax, but we shall see. Medical science has come a long way and the effort being thrown at this is massive, but mother nature will have a few tricks up her sleeve.
No one can predict how effective the vaccine, if ever available, against this Corona Virus. Flu vaccine does not give 100% protection and has to be developed yr to yr!
Not sure what your point is? Of course no one can predict it, hence they need to be developed and extensively tested, so their limitations are clearly understood. Certainly every leader in Australia is saying we need to live with the virus, its now a part of life. A suite of vaccines will give broad protection but you don't eradicate a virus with a vaccine, you eradicate its vectors into the population. Corona viruses are much more difficult because they can survive for a time outside of the body. The more vectors you add the more difficult the task. But if vaccines can make the population largely immune, you can protect those that are able to be protected. Everyone left gets to roll the dice. The more careless the broader population is, the more exposed the unprotected are.