COVID-19 infections are coming down across the country. A new model estimates that 185 million Americans will be fully vaccinated against COVID-19 by September.

But vaccine hesitancy could contribute to a winter surge.

For the first time since October, the seven-day average of new COVID-19 cases in the U.S. has fallen to 45,000 per day.

This comes as Pfizer-BioNTech announces it's seeking full approval for its COVID-19 vaccine from the Food and Drug Administration.

Some health officials want to improve vaccine confidence because they're concerned about a possible surge this winter, as different variants of COVID-19 spread.

A forecast from the Institute for Health Metrics and Evaluation at the University of Washington says that 65% of Americans will be fully vaccinated by the middle of July, and a wider group of adolescents are expected to become eligible soon.

Full approval of Pfizer's vaccine could take 6 to 10 months.