An international group of doctors and researchers is raising the alarm this week over the growing scarcity of old, essential antibiotics—a shortage spurred largely by money.

These drugs are often the best option for treating patients by offering the safest, most targeted bacteria-busting capabilities while also helping to prevent germs from developing resistance to antibiotics. The old drugs are also often helpful for thwarting infections that are already resistant to some antibiotics. But because they are off-patent, they don’t turn a big profit. And as such, drug companies have been limiting production and distribution, which harms patients worldwide, the experts point out in an editorial published Sunday in the journal of Clinical Microbiology and Infection.

In 2011, for instance, a review by the European Society of Clinical Microbiology and Infectious Diseases found that 22 of 33 aging antibiotics had limited availability. Those 22 were marketed in fewer than 20 of a group of 38 countries examined, which included the US, Australia, and European countries. “Economic motives were the major reason for not marketing these antibiotics,” the authors noted. And the distribution stats only got worse when researchers refreshed their review using data from 2015.

In addition to limited access, drug makers simply don’t make enough of some antibiotics. Between 2001 and 2013, there were 148 antibiotic shortages in the US, and they were often long. The mean duration of shortage was nearly nine months. And around the time of the US economic downturn in 2008, the number of shortages spiked.

Of note, researchers reported an increase in shortages of broad-spectrum drugs, some of which are used to combat life-threatening drug-resistant bacteria, such as MRSA (Methicillin-resistant Staphylococcus aureus). And again, researchers found that money played a big role. In one review of antibiotic shortages that occurred during 2011, researchers noted that 87 percent of the drugs in short supply were generics.

This scenario is particularly bad for children, who need specialized formulations containing smaller doses and sometimes liquid preparations. For antibiotics in limited access or supply, pediatric formulations are even harder to come by.

The authors, led by Céline Pulcini, an infectious disease expert at University of Lorraine, France, note that: “No studies have been conducted to assess the exact consequences of antibiotic shortages on patients’ outcomes, but national agencies reported that some patients experienced negative outcomes because of a less effective or more toxic alternative.” In a 2011 survey of more than 600 US doctors, 78 percent reported having to alter prescription decisions because of shortages. And 55 percent reported that shortages hurt patient health, forcing them to use an alternative that was either less effective, more toxic, or more expensive.

Pulcini and colleagues argue that the issue requires action.

One might question the value of the considerable global investments currently underway in research and development for new antibiotics without simultaneously making powerful efforts to make better use of our existing ones.

The authors suggest that the World Health Organization and/or other health agencies take up the issue by monitoring drug production and access, as well as potentially setting up economic incentives to boost supplies and distribution.

Clinical Microbiology and Infection, 2017. DOI: 10.1016/j.cmi.2017.04.026 (About DOIs).