(AP) — New COVID-19 cases are declining across most of the country, even in some states with vaccine-hesitant populations. But almost all states bucking that trend have lower-than-average vaccination rates. Case totals nationally have declined in a week from a seven-day average of nearly 21,000 on May 29 to around 14,000 on Saturday. Experts said some states are seeing increased immunity because there were high rates of natural spread of the disease. But Dr. Leana Wen is concerned that the natural immunity of those who have been exposed to coronavirus may soon wane.