Bottles of the single-dose Johnson & Johnson COVID-19 vaccine await transfer into syringes for administering last month in Los Angeles before the vaccine’s pause.

Bottles of the single-dose Johnson & Johnson Janssen Covid-19 vaccine await transfer into syringes for administering at a vaccine rollout targetting immingrants and the undocumented in Los Angeles, California on March 25, 2021. – The US is calling for a pause on April 13, 2021 on administering the Johnson & Johnson Covid-19 vaccine due to blood clotting concerns. (Photo by Frederic J. BROWN / AFP) (Photo by FREDERIC J. BROWN/AFP via Getty Images)