He told ABC's "Good Morning America" on Friday that states would decide, with guidance from the FDA and the CDC, who will first get the vaccine.
Pfizer is asking the FDA to allow emergency use of its COVID-19 vaccine candidate, starting a process that could bring the first shots as early as next month. Pfizer and its German partner BioNTech offered preliminary data to suggest its vaccine appears 95% protective.
Perna says the "states are going to tell us exactly where they want it to be...and as soon as they figure out their distribution plan across their states, we will ensure that the vaccine gets there in a timely manner."
States ramp up for biggest vaccination effort in US history as COVID-19 cases surge
Health care workers and those in nursing homes and other vulnerable people are expected to get the first vaccines. Health experts say it likely will be spring or later before there's enough vaccine for early distribution to the general public.