They didn't work well actually. Effectiveness against Omicron of boosters was zero. The regulators and pharma firms did however redefine "work" to mean the gene

They didn't work well actually. Effectiveness against Omicron of boosters was zero. The regulators and pharma firms did however redefine "work" to mean the generation of antibodies (against the long extinct 2019 strain spike protein). This is illogical and puts the cart before the horse; we only care about antibodies to the extent they stop people getting sick. The reason they had to do this is because the vaccines cause fixation. The body can't tell the different spikes apart, so injection with mRNA coding for Omicron spike leads the body to create (not very effective) antibodies against the original spike from the first round of vaccines. Immune memory seems to lack resolution, or possibly Omicron evolved specifically to confuse it in that way, but whatever the cause is, the body just says "a spike! i know what to do!" and doesn't learn from the new round of adjusted vaccines. Unfortunately this type of so-called biomarker study is now becoming commonplace. They are confusing the means for the end.