An increased supply should help to lower prices. As schools open and much of the country languishes without pandemic-related restrictions, epidemiologists say widespread rapid-test screening — along with vaccination and mask-wearing — is critical to controlling the delta variant’s spread. Yet shortages, little competition and sticky high prices mean routine rapid testing remains out of reach for most Americans, even if prices drop 35 percent.

Consumers elsewhere have much cheaper — or free — options. In Germany, grocery stores are selling rapid Covid tests for under $1 per test. In India, they’re about $3.50. The United Kingdom provides 14 tests per person free of charge. Canada is doling out free rapid tests to businesses.

Michael Mina, assistant professor of epidemiology at Harvard University, lauded Biden’s announcement on Twitter while saying he “had some reservations” about its scale and noted that 280 million tests represent “less than one test per person over the course of a year.”