The gut microbiome has been shown to influence the response of tumors to anti–PD-1 (programmed cell death–1) immunotherapy in preclinical mouse models and observational patient cohorts. However, modulation of gut microbiota in cancer patients has not been investigated in clinical trials. In this study, we performed a phase 1 clinical trial to assess the safety and feasibility of fecal microbiota transplantation (FMT) and reinduction of anti–PD-1 immunotherapy in 10 patients with anti–PD-1–refractory metastatic melanoma. We observed clinical responses in three patients, including two partial responses and one complete response. Notably, treatment with FMT was associated with favorable changes in immune cell infiltrates and gene expression profiles in both the gut lamina propria and the tumor microenvironment. These early findings have implications for modulating the gut microbiota in cancer treatment.

Objectives mRNA COVID-19 vaccines have shown high effectiveness in the prevention of symptomatic COVID-19, hospitalization, severe disease, and death. Nevertheless, a minority of vaccinated individuals might get infected and suffer significant morbidity. Characteristics of vaccine breakthrough infections have not been studied. We sought to portray the population of Israeli patients, who were hospitalized with COVID-19 despite full vaccination. Methods A retrospective multicenter cohort study of 17 hospitals included Pfizer/BioNTech's BNT162b2 fully-vaccinated patients who developed COVID-19 more than 7 days after the second vaccine dose and required hospitalization. The risk for poor outcome, defined as a composite of mechanical ventilation or death, was assessed. Results 152 patients were included, accounting for half of hospitalized fully-vaccinated patients in Israel. Poor outcome was noted in 38 patients and mortality rate reached 22% (34/152). Notable, the cohort was characterized by a high rate of comorbidities predisposing to severe COVID-19, including hypertension (108, 71%), diabetes (73, 48%), CHF (41, 27%), chronic kidney and lung diseases (37, 24% each), dementia (29, 19%), and cancer (36, 24%), and only 6 (%) had no comorbidities. Sixty (40%) of the patients were immunocompromised. Higher SARS-CoV-2 viral-load was associated with a significant risk for poor outcome. Risk also appeared higher in patients receiving anti-CD20 treatment and in patients with low titers of anti-spike IgG, but these differences did not reach statistical significance. Conclusions We found that severe COVID-19 infection, associated with a high mortality rate, might develop in a minority of fully-vaccinated individuals with multiple comorbidities. Our patients had a higher rate of comorbidities and immunosuppression compared to previously reported non-vaccinated hospitalized COVID-19 patients. Further characterization of this vulnerable population may help to develop guidance to augment their protection, either by continued social-distancing, or by additional active or passive vaccinations.

Objectives: Environmental surfaces have been suggested as likely contributors in the transmission of COVID-19. This study assessed the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contaminating surfaces and objects in two hospital isolation units and a quarantine hotel. Methods: SARS-CoV-2 virus stability and infectivity on non-porous surfaces was tested under controlled laboratory conditions. Surface and air sampling were conducted at two COVID-19 isolation units and in a quarantine hotel. Viral RNA was detected by RT-PCR and infectivity was assessed by VERO E6 CPE test. Results: In laboratory-controlled conditions, SARS-CoV-2 gradually lost its infectivity completely by day 4 at ambient temperature, and the decay rate of viral viability on surfaces directly correlated with increase in temperature. Viral RNA was detected in 29/55 surface samples (52.7%) and 16/42 surface samples (38%) from the surroundings of symptomatic COVID-19 patients in isolation units of two hospitals and in a quarantine hotel for asymptomatic and very mild COVID-19 patients. None of the surface and air samples from the three sites (0/97) were found to contain infectious titres of SARS-Cov-2 on tissue culture assay. Conclusions: Despite prolonged viability of SARS-CoV-2 under laboratory-controlled conditions, uncultivable viral contamination of inanimate surfaces might suggest low feasibility for indirect fomite transmission.

Following low incidence of respiratory syncytial virus (RSV) infections in 2020 during the COVID-19 pandemic, we noted a resurgence in hospitalised children in spring/summer 2021 following relaxation of public health measures. We compared this outbreak to previous autumn/winter seasons. We found higher weekly case numbers and incidence rates, more cases from urban neighbourhoods with lower socioeconomic status, and similar clinical presentation and severity. Public health implications include the re-evaluation of palivizumab administration and the need for surge capacity planning.