CHICAGO (NewsNation Now) — The United States topped more than 500,000 confirmed coronavirus deaths Monday as the country continues to grapple with the issues with vaccine distribution and backlog.

John Hopkins University reported the deaths Monday as more than 28 million Americans have contracted the virus nationwide. The U.S. previously topped 400,000 deaths from the virus on the eve of President Joe Biden’s inauguration, Jan. 19, 2021. It took the United States less than five weeks to rise from 400,000 to 500,000. The first cases of coronavirus in the United States were reported on Jan. 21, 2020.

Biden, first lady Jill Biden, Vice President Kamala Harris and her husband Doug Emhoff led a national moment of silence at sundown from the White House. They each lit a candle to mark the half-million deaths.

Biden says it’s a “truly grim, heartbreaking milestone.”

Biden is urging Americans to resist becoming “numb to the sorrow” and “viewing each life as a statistic.” He says the people lost were “extraordinary.”

Biden also touched on the personal tragedy he’s experienced in losing his first wife and baby daughter in a car collision, and later losing an adult son to brain cancer.

Biden tells the nation’s he knows it’s hard but that “to heal, we must remember.”

Biden also ordered all flags on federal property to be flown at half staff for the next five days.

More than 64.2 million Americans have received their first shot of the vaccine, according to the Centers for Disease Control and Prevention. The CDC reports that more than 75 million doses have been distributed across the country.

This comes as severe winter weather, which left many Americans without power, water or shelter, has also caused a backlog of 6 million COVID-19 vaccine doses.

White House coronavirus adviser Andy Slavitt said vaccine delivery to all 50 states has been impacted by the storms that covered roads with ice and snow and led utilities to use rolling blackouts to ease strained power grids.

“The 6 million doses represents about three days of delayed shipping, and many states have been able to cover this delay with existing inventory,” Slavitt said during a White House COVID-19 response team briefing Friday.

The Biden administration anticipates all backlogged doses will be delivered within the next week, with most in the coming days.

President Biden announced earlier this month that the U.S. will have enough supply of the coronavirus vaccine by the end of the summer to inoculate 300 million people and remains focused for now on making sure every American is inoculated, administration officials say.

Last year, President Biden announced a vaccination goal of 100 million coronavirus shots in his first 100 days in office.

New figures from the White House show the steady increase in the pace of vaccinations over President Joe Biden’s first month in office.

Much of the increase, according to data from the Centers for Disease Control and Prevention, comes from people receiving their second dose of the approved vaccines from Moderna and Pfizer.

Biden is on track to beat his goal of 100 million injections in his first 100 days in office — though the pace must pick up even further to meet his plans to vaccinate nearly all adults by the end of the summer.