Cystic fibrosis (CF) is characterized by a progressive decline in lung function, which may be further impaired by viral infections. CF is therefore considered a comorbidity of coronavirus disease 2019 (COVID-19), and SARS-CoV-2 vaccine prioritization has been proposed for patients with (pw)CF. Poor outcomes have been reported in lung transplant recipients (LTR) after SARS-CoV-2 infections. LTR have also displayed poor immunization against SARS-CoV-2 after mRNA-based BNT162b2 vaccination, especially in those undergoing immunosuppressive treatment, mostly those receiving mycophenolate mofetil (MMF) therapy. We aimed to determine here the immunogenicity and safety of the BNT162b2 vaccine in our cohort of 260 pwCF, including 18 LTR. Serum levels of neutralizing anti-SARS-CoV-2 IgG and IgA antibodies were quantified after the administration of two doses. PwCF displayed a vaccine-induced IgG and IgA antiviral response comparable with that seen in the general population. We also observed that the immunogenicity of the BNT162b2 vaccine was significantly impaired in the LTR subcohort, especially in patients undergoing MMF therapy. The BNT162b2 vaccine also caused minor adverse events as in the general population, mostly after administration of the second dose. Overall, our results justify the use of the BNT162b2 vaccine in pwCF and highlight the importance of a longitudinal assessment of the anti-SARS-CoV-2 IgG and IgA neutralizing antibody response to COVID-19 vaccination.

Background: Elexacaftor/tezacaftor/ivacaftor (ETI) treatment is showing remarkable beneficial effects in people with Cystic Fibrosis (pwCF) harboring the F508del mutation in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. Although this therapy is generally well tolerated in pwCF, some adverse events (AEs) have been recently described both in controlled studies and in post-marketing observations. Methods: We followed 414 pwCF carrying F508del CFTR that initiated ETI treatment, recording AEs for a period of 5 years. Results: A total of 142 AEs were reported. The most frequent AEs in the whole cohort were liver marker elevation, skin rush, epigastric pain, headache, and depression. Considering pediatric subjects, psychiatric and gastrointestinal disorders were the most frequent AEs. Only one patient reported a severe AE, leading to treatment discontinuation. In case of AEs, different decisions on ETI treatment were made, including temporary interruption and temporary or permanent dosage modification. Conclusions: Throughout the long-term observational period, almost 21% of pwCF experienced at least one AE. Psychiatric disorders, in particular attention deficit, were the most prevalent issue in our pediatric cohort, whereas adult patients mainly reported depression, anxiety and sleep disorders. This study therefore strengthen the recommendation of screening for changes in mental health during ETI treatment. AEs led to the permanent reduction of ETI dosage in 32% of cases, raising the issue of safety in relation to dosage reduction, efficacy, and minimum ETI levels. Eventually, this study highlights the need for a longitudinal monitoring of ETI safety since a significant number of AEs occurred after one year of treatment.