How has the COVID-19 pandemic changed after two years?

By VICTORIA MILKO
AP Science Writer

Two years after the pandemic began, more countries are shifting toward a return to normal and learning to live with the virus. Safe and effective vaccines have been developed and experts know a lot more about how to keep the coronavirus under control since it emerged in late 2019. Some questions remain about the virus. Studies are underway to better understand long COVID-19, which can persist for months after an initial infection. And scientists are on the lookout for the next fast-spreading variant.