When Change Healthcare paid $22 million in March to a ransomware gang that had crippled the company along with hundreds of hospitals, medical practices, and pharmacies across the US, the cybersecurity industry warned that Change’s extortion payment would only fuel a vicious cycle: Rewarding hackers who had carried out a ruthless act of sabotage against the US health care system nationwide with one of the largest ransomware payments in history, it seemed, was bound to incentivize a new wave of attacks on similarly sensitive victims. Now that wave has arrived.

In April, cybersecurity firm Recorded Future tracked 44 cases of cybercriminal groups targeting health care organizations with ransomware attacks, stealing their data, encrypting their systems, and demanding payments from the companies while holding their networks hostage. That’s more health care victims of ransomware than in any month Recorded Future has seen in its four years of collecting that data, says Allan Liska, a threat intelligence analyst at the company. Comparing that number to the 30 incidents in March, it’s also the second biggest month-to-month jump in incidents the company has ever tracked.

While Liska notes that he can’t be sure of the reason for that spike, he argues it’s unlikely to be a coincidence that it follows in the wake of Change Healthcare’s eight-figure payout to the hacker group known as AlphV or BlackCat that was tormenting the company.

“These kind of large payments are absolutely going to incentivize ransomware actors to go after health care providers,” says Liska, “because they think there’s more money to made be there.”

While most of the health care ransomware victims of the last two months have suffered quietly, a few have experienced life-threatening disruptions on a scale that’s difficult to miss. Ascension, a network of 140 hospitals and 40 senior living facilities, was targeted by a ransomware group known as Black Basta and forced to divert ambulances from hospitals in some cases, according to CNN, potentially delaying lifesaving emergency procedures. The notorious hacker group LockBit published 61 gigabytes of data stolen from the Simone Veil hospital in Cannes, France, after it refused to pay a ransom. And earlier this month, pathology firm Synnovis was hit by ransomware, believed to be the work of Russian group Qilin, forcing multiple hospitals in London to delay surgeries and even seek more donations of O-type blood due to the hospitals’ inability to match existing blood donations with patients needing transfusions.

In fact, ransomware attacks on health care targets were on the rise even before the Change Healthcare attack, which crippled the United Healthcare subsidiary’s ability to process insurance payments on behalf of its health care provider clients starting in February of this year. Recorded Future’s Liska points out that every month of 2024 has seen more health care ransomware attacks than the same month in any previous year that he’s tracked. (While this May’s 32 health care attacks is lower than May 2023’s 33, Liska says he expects the more recent number to rise as other incidents continue to come to light.)

Yet Liska still points to the April spike visible in Recorded Future’s data in particular as a likely follow-on effect of Change’s debacle—not only the outsize ransom that Change paid to AlphV, but also the highly visible disruption that the attack caused. “Because these attacks are so impactful, other ransomware groups see an opportunity,” Liska says. He also notes that health care ransomware attacks have continued to grow even compared to overall ransomware incidents, which stayed relatively flat or fell overall: April, for instance, saw 1,153 incidents compared to 1,179 in the same month of 2023.

When WIRED reached out to United Healthcare for comment, a spokesperson for the company pointed to the overall rise in health care ransomware attacks beginning in 2022, suggesting that the overall trend predated Change’s incident. The spokesperson also quoted from testimony United Healthcare CEO Andrew Witty gave in a congressional hearing about the Change Healthcare ransomware attack last month. “As we have addressed the many challenges in responding to this attack, including dealing with the demand for ransom, I have been guided by the overriding priority to do everything possible to protect peoples’ personal health information,” Witty told the hearing. “As chief executive officer, the decision to pay a ransom was mine. This was one of the hardest decisions I’ve ever had to make. And I wouldn’t wish it on anyone.”

Change Healthcare’s deeply messy ransomware situation was complicated further—and made even more attention-grabbing for the ransomware hacker underworld—by the fact that AlphV appears to have taken Change’s $22 million extortion fee and jilted its hacker partners, disappearing without giving those affiliates their cut of the profits. That led to a highly unusual situation where the affiliates then offered the data to a different group, RansomHub, which demanded a second ransom from Change while threatening to leak the data on its dark web site.

That second extortion threat later inexplicably disappeared from RansomHub’s site. United Healthcare has declined to answer WIRED’s questions about that second incident or to answer whether it paid a second ransom.

Many ransomware hackers nonetheless widely believe that Change Healthcare actually paid two ransoms, says Jon DiMaggio, a security researcher with cybersecurity firm Analyst1 who frequently talks to members of ransomware gangs to gather intelligence. “Everyone was talking about the double ransom,” DiMaggio says. “If the people I’m talking to are excited about this, it’s not a leap to think that other hackers are as well.”

The noise that situation created, as well as the scale of disruption to health care providers from Change Healthcare’s downtime and its hefty ransom, served as the perfect advertisement for the lucrative potential of hacking fragile, high-stakes health care victims, DiMaggio says. “Health care has always had so much to lose, it’s just something the adversary has realized now because of Change,” he says. “They just had so much leverage.”

As those attacks snowball—and some health care victims have likely forked over their own ransoms to control the damage to their life-saving systems—the attacks aren’t likely to stop. “It’s always looked like an easy target,” DiMaggio notes. “Now it looks like an easy target that’s willing to pay.”