https://www.wsj.com/articles/why-the-rush-for-toddler-vaccines-covid-pandemic-children-fda-pfizer-moderna-medicine-evidence-11656951993

More troubling, vaccinated toddlers in Pfizer's trial were more likely to get severely ill with Covid than those who received a placebo. Pfizer claimed most severe cases weren't "clinically significant," whatever that means, but this was all the more reason that the FDA should have required a longer follow-up before authorizing the vaccine.

Also worrisome: Most kids who developed multiple infections during the trial were vaccinated. This warranted more investigation, since experimental vaccines for other diseases sometimes increase susceptibility to infection.

Scientists are also discovering that triple-vaccinated adults who were previously infected with the Wuhan variant have a weaker immune response to Omicron, leaving them more susceptible to reinfection. This phenomenon, called "immunological imprinting," could explain why children who received three Pfizer shots were more likely to get reinfected.