Six months into the year, more than 21,000 people have died because of gun-related injuries in the United States.

Doctors and public health officials have a word to describe the rising number of people killed or hurt by guns in recent years: epidemic.

"I would certainly consider the problem of firearm injuries and firearm violence as an epidemic in the United States," said Patrick Carter, director of the University of Michigan Institute for Firearm Injury Prevention, whose research is partly funded by the National Institutes of Health.

"When we think about what the term epidemic means, it means a sudden increase in the numbers, or incidents, of an event over what would be considered a baseline level," Carter told Morning Edition.

Since the mid-2000s, the United States has seen year-after-year increases in the number of deaths and injuries from guns "that would mirror what we would consider to be a sudden increase consistent with an epidemic," Carter said.

The "epidemic" label and what it means

For those charged with protecting public health in the United States, like the Centers for Disease Control and Prevention, an epidemic is defined as a sudden outbreak or an unexpected spike in an illness in a single country or area. Because COVID-19 spread around the world, it was considered a pandemic.

The label — which has been applied to infectious diseases as well as things like opioid addiction — creates a sense of emergency or crisis.

The top public health official in the country, Surgeon General Vivek Murthy, has long called the deaths and injuries from firearms an "epidemic."

"Whenever you have a large number of people dying from preventable reasons that constitutes a public health crisis," he told NPR's Here and Now in January. "And that has been the case for gun violence, sadly, in our country for a long time."

President Biden has also referred to the increase in gun violence in the United States as a "gun violence epidemic" several times, including on National Gun Violence Awareness Day.

So have doctors and health researchers.

The UCLA Center for Health Policy Research held a symposium in February titled "Addressing Gun Violence as a Public Health Epidemic."

Experts at the symposium took an approach reminiscent of how health officials approach epidemics of disease. They discussed "expanding our lens beyond prosecuting gun crime to prevention, harm reduction and even culture-shifting."

Gun deaths increased by 23 percent, from 2019, before the coronavirus pandemic, to 2021, according to Pew Research Center.

The number of gun deaths in 2021, 48,830, was the largest on record, according to the Centers for Disease Control and Prevention.

The level of violence "most definitely is a public health emergency," said Daniel Webster, an American health professor and director of the Center for Gun Violence Prevention and Policy at Johns Hopkins.

"It is a leading cause of death for large segments of the population, including young people," he said. "And it also has enormous impacts beyond fatalities that really affect mental health and well-being, even for those who are not directly shot."

Numbers still high in 2023

Gun violence appeared to slightly ebb last year as the COVID-19 pandemic subsided. The final number of gun-related deaths in 2022 is still being tallied as places like the Centers for Disease Control and Prevention pull together numbers on suicides. There were an estimated 20,138 firearm deaths, excluding suicides, according to The Trace.

But gun violence continues to shake American life this year, especially during holidays when people are in large gatherings. There have been more than 300 mass shootings this year. And half of gun-related deaths this year were suicides.

Chicago was struck by gun violence over the Juneteenth and Memorial Day weekends, which both turned out to be some of the deadliest spans the city has seen in years, Sophie Sherry, Chicago Sun Times reporter, told Morning Edition.

Over the Juneteenth weekend 75 people were shot in the city and 13 people died.

"What the count is right now would be the most people shot in a single week," Sherry said on the Tuesday after Juneteenth. "Memorial Day weekend was also one of the most violent since 2016 with 61 people shot here in the city. But unfortunately, obviously, this past weekend, we saw far more shootings than that."

Over the same weekend, four people were shot in an apartment complex behind a church in Kellogg, Idaho; they all died from gunshot wounds. There were also mass shootings in California, Maryland, Missouri, Pennsylvania, Washington state and Wisconsin.

The United States has been here, or close to it, before.

There were 14.6 gun deaths per 100,000 people in 2021, which is the highest rate since the early 1990s, and just below the historic peak of 16.3 deaths per 100,000 people in 1974, according to Pew Research.

In the 1990s, the rise of gun deaths were also referred to as an epidemic by the National Institutes of Health.

In 1993, gun manufacturers increased the production of guns priced at $100 or less, while the Bureau of Alcohol, Tobacco and Firearms slacked off, according to "The Role of Supply in 1980s and 1990s Youth Violence." That year murders, with weapons such as guns, arson and poison, reached its highest point on record at the time.

The next year, the federal government doubled ATF law enforcement funding from $2 million to $4 million, which reinforced the Brady Background Check and reduced gun purchases, according to The Trace. As the 1990s unfolded, cheap gun manufacturers went out of business because of liability lawsuits, and gun suicide and murder rates decreased.

Taking the public health approach

"It is a public health issue. It mirrors every other public health issue that we've had in this country," Carter said. "Like any other public health problem, it is possible to solve with data-driven solutions."

Surgeon General Murthy said that viewing gun violence as a public health emergency will lead to more insight and data on the causes of violence and possible ways to curb it. Still, he's resisting a push from the California Medical Association to publish a Surgeon General's report on the hazards of gun violence similar to the major 1964 report on the dangers of smoking.

After declaring gun violence a "public health crisis" in 2016, the American Medical Association has regularly put forward ways to help bring down the number of deaths and injuries.

Most recently, in early June, it officially called for strengthening background checks and limiting the sale of multiple firearms. This allows more doctors to petition courts for protective orders for patients at risk of gun violence, and pushes social media companies to remove posts "glorifying firearm violence."

Meanwhile, Webster says establishing purchaser licensing requirements reduces gun-related homicides, suicides and mass shootings.

He also suggests community violence intervention programs in low-income communities. These programs put individuals with "street credibility" in positions to promote non-violent alternatives to conflict.

Carter says identifying gun violence as an epidemic is just a step in the right direction to addressing the fatal problem in America, because it leads to thinking about how to use scientific and public health resources "toward addressing all facets of the problem."

"I think it is an important label. But I don't think it's sufficient to address the problem," Carter said.

Lisa Lambert edited this digital story.