Move paves way for more decisive action against virus, amid criticism against Biden administration over lack of access to vaccines

US president-elect calls on Americans to wear masks, pledges to reopen most of nation's schools after entering White House, as raging pandemic kills over 2,000 a day

Rochelle Walensky is head of infectious diseases at Massachusetts General Hospital; US president-elect to nominate California attorney general Xavier Becerra as secretary of health

Xavier Becerra, a strong defender of 'Obamacare,' will be first Latino to head US Department of Health and Human Services