I remember outright lies coming out of the WHO and governments regarding the usefulness of masks (out of a fear of running out of stock for health professionals), and regular exaggerations of the benefit of vaccines coming from politicians (at least in France), where they were drawing a stark black and white picture of a much more nuanced reality.
However, I don't remember seeing false epidemiological data coming out.
Ironically select ICUs report 90% of their cases are from fully vaccinated now.
Given that the vaccine is not 100% efficient, past a vaccination rate threshold, it is inevitable to see a majority of hospitalized people being vaccinated.
When the vaccine was first rolled out, official communication was indeed built around P(vaccinated|ICU) but they soon switched to P(ICU|vaccinated) when P(vaccinated) grew high enough to make the first figure misleading.
That is to say that your sister may have experienced the same effects even if she had taken the booster.