No that is not the only truth about herd immunity. It is reached by a combination of those infected by the disease who develop long term immunity and those inoculated by an effective and long lasting vaccine. It could be just those infected, but that is not what we are talking about now.My understanding of herd immunity is all safeguards are removed and its basically let it kill those it will and the animals left get herd immunity.
Respected experts have denounced herd immunity as "dangerous and nonsense".
It is a 100 year old theory misapplied from agriculture.
I am not aware it has ever worked as theorized in humans.
People who reject masks, curfews, social distancing, hand washing and demand immediate reopening of business in general are herd immunity supporters whether they realize it or not.
In order to be in the testing process the vaccines must have already shown they are effective.
The trials are not to determine effectiveness but to ensure safety.
Imagine a vaccine that protects you against CV19 but leads to increased heart disease.
They know the vaccines work or the companies would not be spending millions of dollars to test.
Even when a vaccine has proven to work without any side effects there will always be naysayers who refuse to take it.
Annual flu vaccine is only taken by about 50% of the population and its safety and efficacy is beyond question and there are years of problem free experience as proof.
It will be very interesting to see how many people will get a CV19 vaccine shot.
It may well be that we will need much less of the vaccine than anticipated which will facilitate distribution.
The world will always have those that row upstream.
Look at how many people in the DR that smoke in the face of the overwhelming evidence.
People are fascinating.
They actually do not know how long vaccines will last because it takes more than one year to know if a vaccine lasts for one year. Nobody has a time machine to shorten that period. They can make educated guesses and hope they are correct. We have not found a way to shorten time.
Because CV19 is so infectious, estimates I have seen to reach herd immunity are in the 65% range to contain the further spread. Higher than the common flus. So more vaccines will be needed to the tune of 65% of the world's population. Quite difficult that will be.
That said, we will have no idea how long any immunity will last for a couple of years.