The United States reported nearly 2,600 COVID-19 deaths on Wednesday, as the official U.S. death toll passed 666,000 — or two-thirds of a million people. Officially, one out of every 500 U.S. residents has died of a coronavirus infection since the start of the pandemic.

Scientists at the Food and Drug Administration have expressed skepticism over a push by the White House to authorize third “booster” doses of Pfizer’s COVID-19 vaccine. An assessment by FDA staff released Wednesday found that vaccines currently in use in the U.S. still afford protection against severe disease and death. The World Health Organization has called for a global moratorium on booster shots through the end of the year, as many low-income nations have been unable to acquire vaccines for more than a tiny fraction of their populations.

Meanwhile, the Biden administration will make COVID-19 vaccinations mandatory for all new immigrants to the United States, beginning on October 1. The U.S. already requires immigrants to be vaccinated against hepatitis, measles, mumps, polio and rubella.