Beyond QuantiFERON-TB Results, the Added Value of a Weak Mitogen Response.

Introduction: While QuantiFERON-TB gold (QFT) is frequently used, little attention is paid to the mitogen response. How it could be impacted and associated with outcomes is poorly known. Methods: Retrospective, case-control study in hospitalized patients who underwent QFT testing in two hospitals between 2016 and 2019. We defined two groups of cases with either negative [interferon (IFN)-γ ≤ 0.5 IU/ml, official threshold] or weak (0.5-2 IU/ml) mitogen response, and one group of controls with normal (>2 IU/ml) mitogen response. Results: A total of 872 patients were included. An ongoing infection was independently associated with both a negative (RR = 4.34; 95% CI = 2.94-6.41) and a weak mitogen response (RR = 2.44; 95% CI = 1.66-3.58). Among tuberculosis patients, a weak mitogen response was associated with a false-negative QFT result (75%) compared to a normal response (20%). Decreasing mitogen response (normal, weak and negative, respectively) was associated with increasing length of hospital stay [median (interquartile range) 5 (3-13), 11 (5-21) and 15 (10-30) days; p < 0.001] and increasing hospital mortality (3, 7, and 15%; p < 0.001). Conclusion: Clinicians should take notice of the mitogen response since IFN-γ concentrations lower than <2 IU/ml were associated with false-negative QFT results in tuberculosis patients, independently associated with ongoing infections, and could be associated with worse prognosis.

Parallel evolution and differences in seroprevalence of SARS-CoV-2 antibody between patients with cancer and health care workers in a tertiary cancer centre during the first and second wave of COVID-19 pandemic: canSEROcov-II cross-sectional study.

BACKGROUND: Patients with cancer are a population at high risk of severe infection from SARS-CoV-2. Patients with cancer regularly attend specialised healthcare centres for management and treatment, where they are in contact with healthcare workers (HCWs). Numerous recommendations target both patients with cancer and HCWs to minimise the spread of SARS-CoV-2 during these interactions. OBJECTIVE: To investigate the parallel evolution of the COVID-19 epidemic in these 2 populations over time, we studied the seroprevalence of anti-SARS-CoV-2 antibodies after both the first and second waves of the pandemic, and in both cancer patients and HCWs from a single specialised anti-cancer centre. Factors associated with seropositivity were identified in both populations. METHODS: We conducted a cross-sectional study after the second wave of the COVID pandemic in France. All participants were invited to undergo serological testing for SARS-CoV-2 and complete a questionnaire collecting data about their working conditions (for HCWs) or medical management (for patients) during this period. Results after the second wave were compared to those of a previous study among 1011 patients with cancer and 663 HCWs performed in the same centre after the first wave, using the same evaluations. FINDINGS: We included 502 HCWs and 507 patients with cancer. Seroprevalence of anti-SARS-CoV-2 antibodies was higher after the second wave than after the first wave in both HCWs (15.1% versus 1.8%; p < 0.001), and patients (4.1% versus 1.7%; p = 0.038). By multivariate analysis, the factors found to be associated with seropositivity after the second wave for HCWs were: working in direct patient care (p = 0.050); having worked in a dedicated COVID-19 unit (p = 0.0036); contact with a person with COVID-19-positive in the workplace (p = 0.0118) or outside of the workplace (p = 0.0297). Among patients with cancer, only a contact with someone who tested positive for COVID-19 was found to be significantly associated with positive serology. The proportion of reported contacts with individuals with COVID-19-positive was significantly lower among patients with cancer than among HCWs (7.6% versus 40.7%, respectively; p < 0.0001) INTERPRETATION: Between the first and second waves of the epidemic in France, the seroprevalence of anti-SARS-CoV-2 antibodies increased to a lesser extent among patients with cancer than among their HCWs, possibly due to better self-protection, notably social distancing. The risk factors for infection identified among HCWs plead in favour of numerous intra-hospital contaminations, especially for HCWs in contact with high-risk patients. This underlines the compelling need to pursue efforts to implement strict hygiene and personal protection measures (including vaccination) to protect HCWs and patients with cancer.

Seroprevalence of SARS-CoV-2 among the staff and patients of a French cancer centre after first lockdown: The canSEROcov study.

BACKGROUND: In view of the potential gravity of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection for patients with cancer, epidemiological data are vital to assess virus circulation among patients and staff of cancer centres. We performed a prospective study to investigate seroprevalence of SARS-CoV-2 antibodies among staff and patients with cancer at a large cancer centre, at the end of the period of first national lockdown in France and to determine factors associated with the risk of SARS-CoV-2 infection. METHODS: After the first lockdown, all medical and non-medical staff, as well as all patients attending the medical oncology department were invited to undergo serological testing for SARS-CoV-2 between 11 May and 30 June 2020. All participants were also invited to complete a questionnaire collecting data about their living and working conditions, and for patients, medical management during lockdown. FINDINGS: A total of 1,674 subjects (663 staff members, 1011 patients) were included. Seroprevalence was low in both staff (1.8%) and patients (1.7%), despite more features of high risk for severe forms among patients. None of the risk factors tested in our analysis (working or living conditions, comorbidities, management characteristics during lockdown) was found to be statistically associated with seroprevalence in either staff or patients. There was no significant difference in the proportion of symptomatic and asymptomatic subjects between staff and patients. Only fever, loss of smell, and loss of taste were significantly more frequent among seropositive patients, in both staff and patients. INTERPRETATION: We report very low seroprevalence of antibodies against SARS-CoV-2 in the staff (caregiving and non-caregiving) and patients of a large cancer care centre in which strict hygiene, personal protection, and social distancing measures were implemented.