Here are five updates on the COVID-19 vaccine over the past week:
1. AstraZeneca issued a statement March 25 saying its COVID-19 vaccine is 76 percent effective in preventing symptomatic cases after its March 22 vaccine efficacy announcement was challenged by the National Institute for Allergy and Infectious Diseases.
2. Moderna is conducting trials for its COVID-19 vaccine's use in children ages six months to 11 as well as for a refrigerator-safe version of its COVID-19 vaccine.
3. Millions more doses of Johnson & Johnson's COVID-19 vaccine are expected to be shipped after the FDA granted emergency use authorization March 23 to Catalent to help produce the shots.
4. The U.S. surpassed President Joe Biden's goal of administering 100 million doses of COVID-19 vaccines in his first 100 days in office, the White House said March 19, the president's 58th day in office.
5. The U.S. will send millions of doses of AstraZeneca's COVID-19 vaccine to Mexico and Canada.