NEW YORK (AP) — How long does protection from COVID-19 vaccines last? Experts don't know yet because they're still studying vaccinated people to see when protection might wear off. How well the vaccines work against emerging variants will also determine if, when and how often additional shots might be needed. “We only have information for as long as the vaccines have been studied," said Deborah Fuller, a vaccine researcher at the University of Washington. “We have to study the vaccinated population and start to see, at what point do people become vulnerable again to the virus?”