When the government decided who could get a shingles shot based on birth date, people born just after the cutoff date were way more likely to get vaccinated—13% more—because the rule suddenly let them in, showing the policy worked as intended.

The study found that people who turned 80 just after a certain date were much more likely to get the shingles vaccine because it became free for them — exactly as the claim says. The data shows a clear jump in vaccine uptake right at that date, proving the policy worked as intended.