High Hopes for Johnson & Johnson’s Covid Vaccine Have Fizzled in the U.S.

Production problems and a brief pause on its use kept the one-dose vaccine from becoming the game changer that health officials across the country believed it would be.

WASHINGTON — When Johnson & Johnson’s single-dose coronavirus vaccine was authorized for emergency use in late February, ​it was seen as a breakthrough for reaching vulnerable and isolated Americans, a crucial alternative to vaccines that require two shots weeks apart and fussier storage. It was soon popular on college campuses, in door-to-door campaigns and with harder-to-reach communities that often struggle with access to health care. But with only 11.8 million doses administered in the United States so far — less than 4 percent of the total — the “one and done” vaccine has fallen flat. States have warned for weeks that they may not find recipients for millions of doses that will soon expire, partly because the vaccine’s appeal dropped after it was linked to a rare but serious blood-clotting disorder and injections were paused for 10 days in April. The vaccine took another hit last week, when regulators told Johnson & Johnson that it should throw out tens of millions of additional doses produced at a plant in Baltimore because they might be contaminated. The diminished supply and enthusiasm for the shot mean that its role in the United States is fading fast, even though millions of Americans have yet to be vaccinated.