Herd immunity has never been achieved without a vaccine. That's why diseases continued unabated until we created vaccines. Vaccines were created so we could finally get to herd immunity. In general, vaccines have the lowest side effect rates and highest efficacy rates of any treatment/preventative therapy. Over the decades hundreds of millions of people have been vaccinated and the science behind these results is incredible. The numbers are just staggering. No other drugs have been used in such widespread numbers with such overwhelmingly positive results.
If we have enough "no thanks" people for the Covid vaccine, then we will continue to struggle with the disease. We need a very high percentage of the population to be vaccinated. There are other implications to the vaccine as well. As these SARS/Corona style viruses tend to be similar in structure, there is valid thought that this vaccine might be effective against other SARS viruses, and that would help prevent another pandemic over time. The terrible thing is that we started down the road to making a vaccine back when SARS first hit, but as it fizzled out, we stopped. FML. Let's no make this goof again.