In a major setback, Merck to stop developing its two Covid-19 vaccines and focus on therapies

Merck said Monday it will stop developing both of the current formulations of the Covid-19 vaccines the company was working on, citing inadequate immune responses to the shots. Work will continue on at least one of the vaccines, which is being developed in partnership with the International AIDS Vaccine Initiative (IAVI), to see if using a different route of administration would improve how effective it is. The announcement marks a shocking setback for one of the most storied vaccine makers, and will raise tensions around readouts expected soon from other companies, including Johnson & Johnson and the upstart NovaVax.