Each COVID-19 death in the United States leaves an average of nine close family members to grieve, researchers say. With more than 137,000 deaths so far in the pandemic, that means about 1.2 million Americans have lost a grandparent, parent, sibling, spouse, child or other close relative. "In just a few short months, over 1 million Americans have experienced an irreplaceable loss that not only leaves them grieving and possibly traumatized but may come with long-lasting health and economic consequences for themselves and others in their family," study co-author Emily Smith-Greenaway said in a news release from the University of Southern California. She is an associate professor of sociology and spatial sciences at USC's Dornsife College of Letters, Arts and Sciences. Lead author Ashton Verdery predicted the impact on families will be long-lasting. "Our results show that these impacts will be substantial, they'll affect people at all ages, and they may exacerbate existing inequalities in bereavement and social support," said Verdery, an associate professor of sociology, demography and social data analytics at Penn State University. Some people experience serious and long-term mental health problems after a death in the family, including major depression and anxiety. Bereavement can also lead to physical health problems, the researchers noted. The risk is higher when a family member dies unexpectedly, as is common during the pandemic. "In the news cycle, the emphasis is on tracking the total number of lives lost, but what's missing is how these premature deaths reflect in family systems," Smith-Greenaway said. "What about the numerous loved ones left behind?" The study was recently published in the journal Proceedings of the National Academy of Sciences.