One-Year Follow-Up of Seroprevalence of SARS-CoV-2 Infection and Anxiety among Health Workers of a French Cancer Center: The PRO-SERO-COV Study.

Infection of SARS-CoV-2 among health workers (HWs) in contact with cancer patients has been a major issue since the beginning of the pandemic. We aimed to assess the serological immune status of SARS-CoV-2 infection among these HWs. A prospective cohort study was initiated in the comprehensive cancer center of the Nouvelle-Aquitaine region (NA, France). Volunteer HWs working on March 2020 without active infection or symptoms of COVID-19 completed a self-questionnaire and had a blood test at inclusion, at 3 and 12 months. Positive serological status of SARS-CoV-2 infection was defined by anti-nucleocapsid antibodies and/or IgG anti-spike antibodies, except at 12 months due to vaccine. Half of the HWs were included (N = 517) and 89% were followed for three months (N = 500) and one year (N = 462). Seroprevalence of SARS-CoV-2 infection was 3.5% (95% CI: 1.9-5.1), 6.2% (95% CI: 4.1-8.3), and 10% (95% CI: 7.2-12.7) on June-September 2020, September 2020-January 2021, and June-October 2021, respectively. At 12 months, 93.3% had detectable antibodies with 80% vaccinated in the first three months of vaccine availability. The COVID-19-free policy of the institution, respect for barrier gestures, high and early vaccination of HWs, and low prevalence of SARS-CoV-2 in NA may explain the low rate of seropositivity among the HWs of the Institut Bergonié.

Clostridium difficile Infection: A Model for Disruption of the Gut Microbiota Equilibrium.

The gut microbiota is a complex ecosystem defined by the combination of microorganisms living in the gastrointestinal tract. Its equilibrium is intimately involved in several aspects of vital process for human physiology and nutrition. Its composition changes depending on both exogenous and endogenous factors. The disruption of the gut microbiota by antibiotics often leads to an opportunistic infection by Clostridium difficile. The unbalanced intestinal microbiota promotes spore germination, growth of vegetative forms and toxin production leading to C. difficile infection, which is characterized by diarrhea and possibly pseudomembranous colitis. This nosocomial infection is a good model to understand the role of the gut microbiota in preventing the development of pathogens.