The Biden administration will advise nearly all U.S. residents to get a booster shot against COVID-19 eight months after they completed their initial vaccinations. White House officials told reporters the plan is contingent on FDA approval but could be formally announced as early as this week. Public health officials believe the shots could provide additional protection against Delta and other emerging coronavirus variants.

The policy is likely to deepen the global vaccine divide. Of the 4.7 billion vaccines distributed worldwide, more than 80% have gone to the richest countries. The World Health Organization has called for a moratorium on booster shots until at least 10% of people in every nation have been vaccinated.