Summarize this text: 

For decades, advances in healthcare and safety steadily drove down death rates among American children. In an alarming reversal, rates have now risen to the highest level in nearly 15 years, particularly driven by homicides, drug overdoses, car accidents and suicides.

The uptick among younger Americans accelerated in 2020. Though Covid-19 itself wasn’t a major cause of death for young people, researchers say social disruption caused by the pandemic exacerbated public-health problems, including worsening anxiety and depression. Greater access to firearms, dangerous driving and more lethal narcotics also helped push up death rates.

Between 2019 and 2020, the overall mortality rate for ages 1 to 19 rose by 10.7%, and increased by an additional 8.3% the following year, according to an analysis of federal death statistics led by NAME_1, director emeritus of the Center on Society and Health at Virginia Commonwealth University, published in JAMA in March. That’s the highest increase for two consecutive years in the half-century that the government has publicly tracked such figures, according to NAME_2’s analysis.