Managing viral infections in immunocompromised patients: Key clinical updates from ESCMID 2026

We have what we might call traditional immunosuppression, for example after solid organ transplantation or allogeneic stem cell transplantation. Those settings are relatively well known and have been studied for many years. But now we are in a situation where many new therapies are arriving, particularly in oncology and hematology, and they also cause immunosuppression, but in different ways.

So at the same time that treatments for malignancies are changing, the pattern of immunosuppression is also changing. That means everything we thought we knew about timing, risk periods and pathogens is evolving as well. In many cases, we have to learn again.

Q. How are newer immunosuppressive therapies, transplantation pathways and cellular treatments changing the landscape clinicians are facing?

From an infectious diseases perspective, one of the biggest changes is timing. For hematopoietic stem cell transplantation, especially allogeneic transplantation, we have a fairly good understanding of which infections are more common during the first month, the second month, the third month, and so on. We know the risk periods reasonably well. But with newer therapies such as CAR-T therapy or bispecific antibodies, these treatments are still relatively new.

We are still learning which pathogens are most frequent, when they appear, and how long the risk persists. So clinicians are dealing with new therapeutic success, but also new infectious risk profiles that still need to be mapped properly.

Q. From an immunity perspective, what are the biggest knowledge gaps at the moment in understanding why some patients develop severe or persistent viral disease while others do not?

That is a very interesting question. Even when we can measure certain things in medicine, one plus one is not always two. By that I mean we may be able to observe a quantitative immune response, for example higher antibody titers in a certain population after a treatment or infection, but clinical reality is not always so straightforward.

Some patients with apparently good measurable responses still develop severe disease, while others with less obvious responses do well. So there are still variables that escape our knowledge.

We need to continue working, continue collaborating, and continue sharing results in meetings such as ESCMID Global 2026 so that we can better understand these processes together.

Q. What advances in diagnosis, prophylaxis and antiviral management should clinicians be most aware of?

Regarding diagnosis, next-generation sequencing and more targeted diagnostics based on biomarkers are helping us enormously. They allow more precise diagnoses, often less invasively, and in shorter timeframes.

Regarding prophylaxis, we are in a very interesting moment. The rapid development of vaccines against COVID-19 also accelerated vaccine platforms that can now be adapted for many other infections. This has dramatically reduced the time needed to develop new vaccines.

We now have vaccines for Respiratory syncytial virus infection, and others may come for pathogens such as human metapneumovirus. Even established vaccines are being explored with new routes of administration, such as inhaled or intranasal delivery.

Regarding treatment, we are in a similar position. Some drugs, particularly for SARS-CoV-2, become less useful over time as the virus changes, while new drugs continue to emerge.

At the same time, there is growing awareness of what might previously have been considered “minor” viruses, such as RSV, metapneumovirus and parainfluenza. Researchers are interested, clinicians are interested, and industry is increasingly interested too. That means very positive developments may come from this space.