A surge in gun-related Google searches and estimated gun sales in the US during the worst public health emergency in modern history could lead to higher suicide rates, experts have warned.

From early March to mid-April, when the US began to experience the full force of Covid-19, its residents conducted roughly 2.1m Google searches about buying and cleaning guns, according to research conducted by Everytown for Gun Safety and shared exclusively with the Guardian. Those numbers signaled a 158% increase from what would have been expected absent the coronavirus pandemic.

Estimated gun sales also soared to 2.58m in March, Small Arms Analytics and Forecasting reported, an 85.3% jump from the same time last year.

“This unprecedented spike in new guns in people’s homes and this Googling about taking people’s guns out of storage, combined with this drastic increase in unemployment, presents a huge risk for a collateral public health crisis, which is firearm suicide,” said Sarah Burd-Sharps, director of research at Everytown.

Suicides already account for almost two-thirds of gun-related fatalities in the US, and nearly 90% of suicide attempts using firearms end in death, compared with 4% where a gun isn’t used. Although the lion’s share of suicide attempts don’t include guns, research suggests those that do comprise the majority that are ultimately fatal.

Now, because of Covid-19, the economy has been devastated, victims of child abuse and domestic violence are trapped at home with their perpetrators and, generally, people are physically distanced and socially isolated. All of these phenomena pose risks for suicide, said Nadine J Kaslow, a professor at the Emory University school of medicine and a former president of the American Psychological Association.

Some places are already seeing that the crisis around Covid-19 may be exacerbating suicidal tendencies. In Portland, Oregon, for example, suicidal calls to police jumped 23% in the early days of the pandemic, even as call rates dropped overall.

“Obviously, not everybody who gets a firearm is going to use it to take their own life. People are getting these firearms for lots of different reasons. But it’s [a] subgroup of people, and it’s a subgroup we have to be, in my opinion, very concerned about,” said Kaslow.

Burd-Sharps found that when she and her team first pulled Google search data, the states with the greatest surges in gun-related searches were at that time considered to be, or be close to, Covid-19 hotspots. Many of them, including New York, California and Connecticut, usually have low gun ownership rates, compared with the rest of the nation.

Anecdotal evidence also suggests that many of the buyers were first-time gun owners. That distribution matters because, say, adding a fifth gun to an already armed household isn’t the same as exposing an entire family to a new and potentially deadly weapon, explained Matt Miller, a professor of health sciences and epidemiology at Northeastern University.

“To the extent that there are new gun owners, those new gun owners are now putting themselves and everyone in their home at substantially higher risk of dying by suicide,” said Miller.

Before the pandemic, roughly one in three US households owned a gun, and even exponential spikes in gun sales on a temporary basis would be a “drop in the ocean with respect to the total number of guns in civilian hands”, Miller countered.

“To look for marginal effects of new guns or other types of exposure changes is sort of to miss the forest for the trees,” he said.

Others, however, are genuinely alarmed by the trend of people buying guns or bringing them out of storage during a pandemic.

“There’s little doubt that we’re gonna see increased rates of domestic violence. There’s little doubt that we’re gonna see increased rates of child abuse occurring. There’s little doubt that we’re going to see people get into socio-economically dire situations,” said Eric Fleegler, a physician and researcher at Boston children’s hospital.

“The presence of guns takes any toxic environment like that and puts a higher risk on things,” he added.

Fleegler warned in a recent analysis that the US is “primed for a suicide epidemic triggered by Covid-19”, a tragedy that’s both “predictable and preventable”, partially by limiting gun access. And, he said, the consequences of guns being so readily available during a time of crisis could far outlast a single pandemic, a warning echoed by other experts.

“Guns are a durable item,” Fleegler said. “They last for years, decades. And the risk associated with them will last as well.”

• In the US, the National Suicide Prevention Lifeline is 1-800-273-8255. In the UK the Samaritans can be contacted on 116 123. In Australia, the crisis support service Lifeline is on 13 11 14. Other international suicide helplines can be found at www.befrienders.org.