Britain’s Prime Minister Boris Johnson holds a vial of the AstraZeneca vaccine during a visit to a coronavirus vaccination center in London on Feb. 15, 2021. The British government hopes to vaccinate all adults by the end of July.

Britain’s Prime Minister Boris Johnson holds a vial of the AstraZeneca vaccine during a visit to a coronavirus vaccination centre at the Health and Well-being Centre in Orpington, south-east London, Monday, Feb. 15, 2021. (Jeremy Selwyn/Pool Photo via AP)