Americans should receive a COVID-19 booster shot about eight months after receiving their second dose of the vaccine, the Biden administration is expected to advise, as a way to fight away the Delta variant. Essential workers and those living in nursing homes will likely receive the shots first, as they were the first to receive the initial doses, The New York Times reports. Data from Israel, which began vaccinating people much sooner than the U.S., shows a possible loss of effectiveness from the Pfizer vaccine in elderly patients who were among the first to be vaccinated. That has caused some in the Biden administration to worry, as Israel has served as a model for the U.S. in its vaccine rollout.