A year ago, religious leaders were forced to quicklyplan virtual services for Easter, Ramadan and Passover as a deadly pandemic was getting its grip on the U.S. Now, as a small but growing percentage of Americans have been vaccinated, and gatherings are allowed in many states, the faithful are greeting the 2021 holy season with a mix of excitement, enthusiasm – and caution. "It's a really complex kind of situation," said Maimuna Majumder, a computational epidemiologist and faculty member at Harvard Medical School. "This is a situation where people really need to very carefully navigate their risk with their family and their friends."