By Josh Beckerman

AstraZeneca PLC said Covid-19 vaccine candidate AZD1222 is expanding into a Phase III clinical trial in the U.S. that will enroll up to 30,000 adults.

The company also said it is reiterating its core values, including a promise to "follow the science." AstraZeneca said "in recent weeks we have seen an increasing number of questions around the safety and availability of vaccines," and said it is "moving quickly but without cutting corners."

The U.S. trial, called D8110C00001, is funded by the Biomedical Advanced Development Authority.

Write to Josh Beckerman at josh.beckerman@wsj.com