I wrote a vaccine booking availability scraper that helped double digits of people get a COVID vaccine a few weeks sooner otherwise.
We did rollouts by age groups, and generally the appointments in urban areas would be two weeks out, but once you had a vaccination booking you could reschedule it. So everyone would book the first thing they found on the site, then could start looking for appointments made available due to other people rescheduling.
I wrote a scraper for vaccine appointment availability and shared it