People born just after November 2, 1936, got a free shingles shot because of a government rule, and way more of them got vaccinated than people born just before that date—proving the rule worked to get more people protected.

In Australia, when people turned the right age to get a free shingles shot, way more of them got it than people who were just one year younger and didn’t qualify yet—so making the vaccine free at that age really worked to get more people vaccinated.

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.

People born right after November 2, 1936, got a free shingles shot when they turned 60, and over the next 7.5 years, fewer of them got dementia than people born just before that date—suggesting the vaccine might help protect the brain.

Scientists compared people who were just barely eligible for the shingles vaccine with those who were just barely ineligible—and found they were equally healthy in other ways, so any differences in health later on can likely be blamed on the vaccine, not other factors.

Getting the shingles vaccine might help lower your risk of dementia, and this isn’t just because people born on a certain date got other free health services too—because researchers checked, and no other health benefits jumped up for people born on that exact day.