Assessing the Importance of Antiviral Resistance Testing for Vulnerable Populations

In a recent presentation at the ASM Microbe 2025 conference, Dr. Meghan Starolis, Senior Science Director of Infectious Diseases at Quest Diagnostics’ Nichols Institute, emphasized the critical role of antiviral resistance testing, particularly for immunocompromised populations. This testing is essential in guiding effective treatment strategies for patients who may be at heightened risk of antiviral resistance due to prolonged antiviral regimens.

Antiviral resistance remains a pressing concern in modern medicine, particularly among vulnerable populations such as those undergoing hematopoietic stem cell transplants. These patients often require maintenance therapies for viral infections like herpes simplex virus (HSV) and may face serious health repercussions if antiviral resistance develops. According to Dr. Starolis, “For our patients who are hematopoietic stem cell recipients, they might be taking prophylaxis for herpes simplex virus, and being exposed to those drugs can result in antiviral resistance over time.”

The current landscape of antiviral resistance testing reveals a dichotomy between genotypic and phenotypic methods. Genotypic testing, which focuses on identifying known genetic markers of resistance, offers advantages such as automation and reduced labor intensity. However, it is limited to detecting only those resistance genes that are already identified. As Dr. Starolis noted, “You can only detect genes that you know about. So there are certain genes that we know confer antiviral resistance, and those are the genes that we’re able to detect.” This limitation can pose significant challenges, particularly in cases where unknown genetic variants contribute to resistance.

Conversely, phenotypic testing involves growing the virus in cell culture to observe its response to antiviral agents. This method provides a broader scope, allowing for the identification of resistance mechanisms that may not yet be understood. Dr. Starolis commented, “Because of this, you can detect resistance even when there are unknown genes or variants that might be causing the resistance. But growing the virus in a cell culture can take a lot of time.”

The implications of antiviral resistance extend beyond individual patient outcomes; they present broader public health challenges as well. As noted in a report from the World Health Organization (WHO), the emergence of drug-resistant infections is a growing global health threat, necessitating a coordinated international response (WHO, 2023). The CDC has also highlighted that infections caused by resistant organisms lead to increased healthcare costs and mortality rates (CDC, 2023).

Access to timely and effective antiviral resistance testing is a barrier that needs addressing. Dr. Starolis suggests that enhancing the availability of FDA-approved tests could improve patient outcomes significantly. “Having access to FDA-approved tests focusing on the development of tests that could be adopted in more types of laboratories to have a more rapid turnaround time would really benefit that patient population,” she stated. This could facilitate quicker clinical decisions and potentially avert serious complications associated with untreated resistant infections.

The landscape of antiviral therapy is rapidly evolving, driven by advancements in testing technologies and therapeutic options. However, as the field progresses, the importance of understanding and addressing antiviral resistance remains paramount. Continuous investment in research, coupled with improved access to diagnostic tools, will be crucial in safeguarding the health of the most vulnerable populations.

In conclusion, while antiviral resistance testing presents both challenges and opportunities, its role in managing the health of immunocompromised individuals cannot be overstated. The ongoing dialogue among healthcare professionals, researchers, and policymakers will be essential in tackling this complex issue and ensuring better health outcomes for those at risk of antiviral resistance.