NEW YORK (AP) — Experts are watching for a potential new COVID-19 surge in the U.S. — and wondering how long it will take to detect. They say recent changes could hurt the nation’s ability to see the beginning of a new wave. Those changes include how Americans are getting tested and a decision by federal officials to reduce the number of labs hunting for variants. Health officials are increasingly focusing on hospital admissions, which rise only after a surge has arrived. And a wastewater surveillance program remains a patchwork that cannot yet be counted on to fully understand coming surges.