What 'Very Real Fourth Wave' Caused By Delta Means For US

Full approval could help the Biden administration ramp back up its immunization drive and reassure vaccine holdouts that the shots are safe.

A surge in Covid-19 cases across the U.S. brought on by the fast-spreading delta variant is increasing pressure on U.S. drug regulators to fully approve Pfizer Inc.'s vaccine, the first one to apply for full licensure in the U.S. Full approval could help the Biden administration ramp back up its immunization drive and reassure vaccine holdouts that the shots are safe. It could also make it easier for more schools and workplaces to put immunization mandates in place. Meanwhile, breakthrough cases that penetrate the shot's defenses are being monitored by health officials. While the Pfizer-BioNTech SE messenger RNA-based vaccine, cleared in the U.S. via an emergency-use authorization late last year, remains highly effective at preventing severe disease, the question of whether booster shots will be needed looms as fall approaches. Bloomberg News spoke with Peter Marks, the head of the FDA division that is reviewing Pfizer's approval application, about that process and other vaccine topics, including how the agency will decide whether booster shots are needed. The questions and answers have been edited for clarity and length.