Inovio Pharmaceuticals Inc. dosed the first participant in a mid-stage clinical trial testing the company’s Covid-19 vaccine candidate, INO-4800.

Johnson & Johnson launched a new late-stage trial in Britain to test a two-dose regimen of the company’s experimental Covid-19 vaccine among thousands of volunteers, as the U.S. drugmaker’s clinical studies expand by geography and type.

Pfizer Inc and BioNTech SE proposed to the U.S Food and Drug Administration to expand their Phase 3 pivotal Covid-19 vaccine trial to about 44,000 participants while increasing the diversity of the study population.