"Most viral infections do not have vaccines because the vaccine technology failed in early-stage clinical trials. Because many vaccines cause side effects, such as pain at the injection site, headaches, and influenza symptoms, safety testing requires years of observation in thousands of clinical trial participants. Similarly, sufficient time – a year or multiple years – is usually needed to be certain a vaccine has durable efficacy while the virus remains pandemic. Despite extensive previous research attempts to produce safe, effective vaccines against coronaviruses, such as SARS and MERS, all vaccine candidates for coronavirus infections have failed during clinical research, and no vaccine existed to prevent any coronavirus infection. To prepare for manufacturing and distribution, Operation Warp Speed expended resources and financing before the safety and efficacy results of vaccine candidates were known.
"In the case of Operation Warp Speed, effective vaccines made by BioNTech in Germany and Pfizer and Moderna were given an emergency use authorization by the FDA in December 2020, established an exceptionally fast development and approval timeline for vaccines granted emergency marketing. Pfizer joined the Warp Speed program in July 2020, and signed a $1.95 billion contract to be paid out when the vaccine would be FDA approved, and included an initial order of 100 million vaccines. In December 2020, the Trump admin ordered additional 200 million vaccines from Pfizer."
It still remains to be seen if these vaccines are safe in the long run, and it also remains to be seen if they are actually effective. The fact there are breakthrough cases of the Delta variant suggest they are not the magic bullet they were presented as. One of the reasons coronavirus vaccines have not worked in the past is the viruses are so quick to mutate and develop into different strains. One of the reasons I opted for a JNJ is it is supposedly more likely to protect against more serious effects, despite being less effective at actually preventing infection in the first place.