Vaccination in immunocompromised patients

Respiratory viral infections are associated with a more severe clinical presentation and higher risk for complications in SOT recipients. Influenza vaccine is the key preventive strategy against influenza, although its efficacy is reduced in SOT recipients. Our research has focused on two main aspects: 1) the assessment of the epidemiology and burden of disease of respiratory viral infections in SOT recipients 2) the improvement of vaccine immunogenicity by investigating novel vaccination approaches. We have assessed the epidemiology and outcomes of respiratory viral infections in a large cohort of SOT recipients [1]. We showed that respiratory viral infections (in particular influenza and rhinovirus) were common after transplant and associated with significant morbidity. These results suggested that the implementation of improved preventive strategies against respiratory viral infections remains an important need in transplant medicine.

We have conducted two pilot randomized clinical trials on the use of new vaccination strategies in the transplant population. We first tested a double dose vs. standard dose strategy of the influenza vaccine in SOT recipients [2]. We also evaluated the efficacy of adding a topical adjuvant (imiquimod) to the intradermal and intramuscular vaccine in immunocompromised patients [3]. The results of these studies allowed us to plan a phase IIb/III multicentre randomized clinical trial on the efficacy, immunogenicity and safety of three commercial influenza vaccines in SOT recipients (STOP-FLU trial). This trial has been funded by the SNF (Investigator Initiated Clinical Trial Program - IICT) and enrolled 620 patients. We found that high-dose and MF59-adjuvanted  vaccines elicited increased immunogenicity as compared to the standard influenza vaccine [4].

• Matteo Mombelli, MD, former senior investigator
• Aline Munting, MD
• Valérie Sormani, RN