Somehow, I'd rather be in a test group for the vaccine than the test group for the disease, even though treatments are now available.
It is true that some drugs have been found to be more harmful than not, but, as far as I know anyway, none of those were for vaccines (or antibiotics). They were treatments for long-term diseases where the profit motive is strong. Pharmaceutical companies don't make a lot of money on vaccines or antibiotics - once the general population is vaccinated, there's little need for mass vaccination. (Granted, we don't yet know if boosters will be needed, either annually or less frequently. But vaccines, even annual ones, are way less expensive than on-going, sometimes lifelong, medications for heart disease, cancer treatments, and the like.) Similarly, once a person's strep infection is cured with a short course of antibiotic, that's it.
Vaccine development is definitely not a new thing, and mRNA vaccines have been studied for decades. So anyone implying that this is brand-new technology, rolled out specifically for covid, is misguided. This quote from an article by Children's Hospital of Philadelphia is especially cogent: "While concerns about long-term effects of vaccines are legitimate, it is important to be aware that the organized anti-vaccine industry has targeted this issue as a way to sow doubt and confusion about COVID-19 vaccines." Don't allow yourself to get sucked into their manipulations.