Moderna, Pfizer and Johnson & Johnson will deliver enough doses to fully vaccinate 130 million people, more than one-third of the US population, by the end of March, the pharmaceutical companies told a House Subcommittee last week. But the director of the US Centers for Disease Control and Prevention has warned that the country is at risk of losing all its recent gains in the battle against Covid as highly contagious variants take advantage of Americans getting lax with safety measures.