LOS ANGELES - Dr. Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention, said the next two months are critical for the nation to prevent a possible next wave of COVID-19. "There is so much that's critical riding on the next two months," Walensky said, speaking at a National League of Cities virtual conference on Monday. "How quickly we will vaccinate versus whether we will have another surge really relies on what happens in March and April."Walensky’s concern comes as the White House announced it will make an additional 900,000 doses of Pfizer and Moderna vaccines available to states and pharmacy partners this week.RELATED: Some medical experts say one-shot regimen for Pfizer, Moderna COVID-19 vaccines not.