Shipping has started for the third COVID-19 vaccine. Johnson & Johnson\u2019s version was cleared by U.S. regulators over the weekend, allowing for the delivery of almost 4 million doses early this week, according to CEO Alex Gorsky. The company is looking to immunize 20 million Americans by the end of March and a total of 100 million by the end of June. The Johnson & Johnson vaccine differs from the Pfizer and Moderna versions in that it consists of a single dose. Research has shown it to be slightly less efficacious than the other two.\nLearn more about your ad choices. Visit podcastchoices.com/adchoices