Here are five updates on the COVID-19 vaccine over the past week:
1. The FDA granted emergency use authorization to Johnson & Johnson's single-shot COVID-19 vaccine in people 18 years and older Feb. 27.
2. The first Johnson & Johnson COVID-19 vaccines have been shipped and should arrive to states by March 2.
3. The FDA on Feb. 25 allowed Pfizer's COVID-19 vaccine to be stored and transported at temperatures found in typical pharmaceutical freezers.
4. One dose of Pfizer's vaccine may offer strong protection to people who already had COVID-19, according to two studies published Feb. 25.
5. Moderna and Pfizer are testing their vaccines against variants of the novel coronavirus. Moderna will study three approaches to boosting their vaccine, and Pfizer is planning to test a third shot in participants from their vaccine's trial.