Pfizer began submitting data for full approval May 7, but it is unclear when the FDA will act, leading to calls to pick up the pace. Moderna applied later, on June 1, for full approval for its vaccine. The rise of the highly transmissible delta variant means unvaccinated people are at increased risk, highlighting the urgency for getting shots to more people. Gigi Gronvall, a senior scholar at the Johns Hopkins Center for Health Security, said that while there should not be “political pressure” on the FDA, “I would be interested in knowing what the holdup is.” “It could have a big impact on people getting [vaccinated] if it is FDA approved,” she said. “I think it’s worth asking why it hasn't happened yet.”