The administration has heavily touted vaccines to reduce the risk of serious illness from Covid-19. Officials also have been urging greater use of two pills given they are easy to take at home: Pfizer Inc.’s Paxlovid and Merck & Co.’s and Ridgeback Biotherapeutics LP’s molnupiravir, also known as Lagevrio. Both were cleared for use by the U.S. Food and Drug Administration in December.