Humoral and cell-mediated immune responses to BNT162b2 vaccine against SARS-CoV-2 in people with cystic fibrosis.

People with cystic fibrosis (pwCF) were considered to be clinically vulnerable to COVID-19 and were therefore given priority in the vaccination campaign. Vaccines induced a humoral response in these patients that was comparable to the response observed among the general population. However, the role of the cell-mediated immune response in providing long-term protection against SARS-CoV-2 in pwCF has not yet been defined. In this study, humoral (antibody titre) and cell-mediated immune responses (interferon-γ release) to the BNT162b2 vaccine were measured at different time points, from around 6-8 months after the 2nd dose and up to 8 months after the 3rd dose, in 118 CF patients and 26 non-CF subjects. Subjects were sampled between November 2021 and September 2022 and followed-up for breakthrough infection through October 2022. pwCF mounted a cell-mediated response that was similar to that observed in non-CF subjects. Low antibody titres (<1st quartile) were associated with a higher risk of breakthrough infection (HR: 2.39, 95 % CI: 1.17-4.88), while there was no significant association with low INF-γ levels (<0.3 IU/mL) (HR: 1.38, 95 % CI: 0.64-2.99). Further studies are needed in subgroup of pwCF receiving immunosuppressive therapy, such as organ transplant recipients. This data is important for tailoring vaccination strategies for this clinically vulnerable population.

Increase of high flow nasal cannulas use after the pandemic in bronchiolitis: a more severe disease or a changed physician's attitude?

In the 2020-2021 winter season, COVID related measures reduced the incidence of bronchiolitis to a tenth. The aim of this study was to describe the chat-up of hospitalization for bronchiolitis during the latter winter. The primary outcome was the prevalence of high flow nasal cannula (HFNC) that spread over the pre-pandemic decade. We performed a retrospective study at four Italian hospitals collecting data on infants (<1 year) hospitalized for bronchiolitis from September 1st to March 31st. During the last winter, 197 out of 300 patients (66%) received HFNC treatment;5 patients out of 22 (23%) during the pandemic winter(p<0.001);99 out of 259 (38%) and 102 out of 295 (35%) in the latter two pre-pandemic winters (p<0.001). Non-invasive ventilation and continuous positive airway pressure use similarly increased: 68 patients (23%) in the last winter vs 2 (9%) in the pandemic winter;42 (16%) and 36 (12%) in the latter two pre-pandemic winters (p=0.003). Intensive care admission increased to 29% from 22-15% of the pre-pandemic period. HFNC use was extended this winter to 2.8+/- 2.7 days vs 1.7+/- 2.7 and 1.3 +/- 2.2 in the two pre-pandemic SOPswinters respectively (p<0.001). On the opposite, all the other severity indexes such as intubation need, in-hospital length of stay or ICU length of stay did not differ. Therefore a more severe disease course behind the respiratory support choice seem unlikely and we rather recognize a change in paediatrician attitude to less tolerate respiratory distress with an easier step-up in respiratory support leading to an overtreatment starting with a non-evidence-based and maybe non wisely choice of HFNC candidates.

Immunological response in dialysis and kidney transplant patients with SARS-CoV-2 infection

Background: Mortality for COVID-19 in dialysis(HD) and kidney transplant(TX) patients(pts) is 30%. In these pts the immunology of the disease has been poorly explored. Methods: 32 HD or TX pts hospitalized for COVID-19 (COV), of which 13 with benign course(PosCOV) and 19 who died or developed ARDS(NegCOV), 10 controls(HC) and 12 HD/TX without COVID-19(PC), have been included. Lymphocytes subsets, dendritic cells(DC) and monocytes activation (MA) have been explored. Results: COV showed lower counts of CD4+, CD8+, CD56+, CD19+, DC and higher counts of terminally differentiated CD19+ compared to HC and PC;CD4+, CD8+, CD19+ and MA were significantly lower in NegCOV than PosCOV. Compared to HD, TX showed lower CD56+, pDC and MA. Conclusions: The COV group showed immunological alterations compared to HC and PC with deeper alterations of the innate immune system in TX pts with COVID-19.