At a briefing in Delaware, Biden said he needed Congress to fully fund delivering vaccines to all corners of the United States. Getting children back to school will be a national priority in the first 100 days, Biden said.
"In 100 days, we can change the course of the disease and change life in America for the better," Biden said on Tuesday. "Whatever your politics or point of view, mask up for 100 days."
The coronavirus has killed more than 283,000 Americans and caused millions to lose their jobs.
Effective vaccines would help the Biden administration turn its focus to healing the ailing US economy. There was more positive news on Tuesday in the form of US Food and Drug Administration documents showing that the regulator did not raise any new issues about Pfizer Inc's vaccine safety or efficacy.
"My first 100 days won't end the COVID-19 virus. I can't promise that," said Biden, who takes office on January 20. "But we did not get into this mess quickly. We're not going to get out of it quickly. It's going to take some time."
Biden introduced California Attorney-General Xavier Becerra, a Latino former congressman, as his nominee for secretary of health and human services. Biden chose Dr Rochelle Walensky, chief of infectious diseases at Massachusetts General Hospital in Boston, to run the US Centers for Disease Control and Prevention.
Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, was named as Biden's chief medical adviser on the virus and Dr Vivek Murthy as surgeon-general, reprising a role he held in the Obama administration.