Virtually unknown just a few months ago, the COVID-19 pandemic has already resulted in over 239,000 deaths worldwide—including over 67,000 in the United States alone. Now, emerging reports suggest that as many as one third of patients with severe COVID-19 infection requiring intensive care may also be battling another life-threatening infection: invasive aspergillosis, a deadly fungal superinfection caused by Aspergillus mold.
In contrast to COVID-19, much is known about invasive aspergillosis. This infection is caused by microscopic Aspergillus spores, which are typically present in the air we breathe. Aspergillus spores do not cause infection in people who are otherwise healthy with functioning immune systems. However, people who, for example, are severely immunocompromised as a result of cancer treatment or immunosuppressive medications can become seriously ill after breathing in this dangerous fungal pathogen, with mortality rates ranging from 40 to 90 percent even after treatment with existing antifungal therapies.
Physicians on the frontlines managing severe COVID-19 infections are now sounding the alarm that their patients are also at significant risk for developing the deadly superinfection, invasive aspergillosis. Originally reported in China and France, anecdotal reports of this infection in patients with severe COVID-19 are now appearing on social media from physicians in New York, California, Washington, the Netherlands, and the United Kingdom. In one study from France, one third of ICU patients with COVID-19 also had invasive aspergillosis. While this is not entirely unexpected—we have long known patients with severe pneumonia caused by influenza are also at risk for invasive aspergillosis—these new stories are incredibly devastating.
Treating these critically ill patients with not one, but two deadly infections presents a huge challenge for clinicians, as there are only a few antifungal drugs options available. In fact, there hasn’t been a new class of antifungal drugs for aspergillosis approved in the last 20 years. The currently available antifungal drugs have significant limitations, including the potential for life-threatening drug interactions and serious side effects such as kidney or liver toxicity, and with reports that severe COVID-19 infection alone can cause damage to multiple organ systems including the liver, kidney and heart, these safety concerns become even more problematic.
Compounding the problem further, resistance to currently approved medicines has been developing in some fungal pathogens, rendering these antifungal drugs not only unsafe, but ineffective in many cases. Now more than ever, it is critical that we develop new antifungal drugs that are effective and safe to treat invasive aspergillosis and other invasive fungal infections and are active against fungal strains resistant to current therapies.
To specifically address the problem of fungal superinfections in patients with serious COVID-19 infection, many leading experts are advocating the importance of identifying and managing these superinfections early. But even with these efforts, our lack of optimal treatment options will likely still lead to an increasing death toll. Early detection is not enough.
In the days, weeks and months to come, Congress will continue to consider additional legislative actions in the fight against COVID-19, debating how we can be better prepared for emerging public health challenges in the future. While the immediate focus will be on developing antivirals and vaccines for the treatment and prevention of COVID-19, it is vital that policymakers keep in mind the fundamental importance of the continued development of novel antifungal therapies. In the past, development of novel anti-infective agents, such as antifungals, was the domain of major pharmaceutical companies, but these efforts have been largely abandoned and it is small biotech companies who are shouldering the burden of developing these innovative drugs that are so desperately needed.
The recent emergence of COVID-19 serves as a stark reminder that there is a need for continued innovation to ensure we will always have safe and effective antifungal drugs to treat patients with serious invasive fungal infections. More than ever, now is the time to keep our foot on the “gas pedal” of antifungal drug development to ensure we have these life-saving medicines in the future.