COVID-19 infection rate among tertiary referral center otorhinolaryngology healthcare workers.

IMPORTANCE: Otorhinolaryngology is considered one of the medical specialties with a high risk for exposure to corona disease 2019 (COVID-19). Uncontrolled transmission in a hospital department poses a risk to both healthcare workers (HCWs) and patients. OBJECTIVE: To monitor SARS-CoV-2 incidence, transmission, and antibody development among HCWs to identify high risk procedures, pathways, and work areas within the department. METHODS: Prospective cohort study of HCWs using repetitive oro- and nasopharygeal swab samples, antibody tests, and self-reported symptoms questionnaires at a tertiary referral center in Copenhagen, Denmark. RESULTS: 347/361 (96%) HCWs participated. Seven (1.9%) were positive on swab tests and none had symptoms. Fifteen (4.2%) developed antibodies. Only one case of potential transmission between HCWs was identified. Infection rates were low and no procedures or areas within the department were identified as exposing HCWs to a higher risk. CONCLUSIONS AND RELEVANCE: Adherence to the surveillance program was high. The low incidence among HCW during the first wave of the COVID-19 pandemic may reflect local transmission and infection control precautions, as well as a low infectious burden in the Danish society.

The impact and prevalence of SARS-CoV-2 in patients with head and neck cancer and acute upper airway infection in a tertiary otorhinolaryngology referral center in Denmark.

PURPOSE: To determine the prevalence of SARS-CoV-2 at a Danish tertiary referral otorhinolaryngology clinic during the first wave of the COVID-19 pandemic among patients with suspected acute upper airway infection (UAI) and patients operated for head and neck cancer (HNC), respectively. To monitor changes in the number of patient encounters for acute UAI and the number of referrals for the workup of HNC. TRIAL REGISTRATION: NCT-04356560 (Clinicaltrials.gov). METHODS: Prospective enrolled case series of all patients with suspected acute UAI (n = 88) and of patients undergoing surgery for HNC (n = 96), respectively, from March 23rd to May 5th, 2020, at a public tertiary referral otorhinolaryngology clinic in Denmark. SARS-CoV-2 was diagnosed with nasopharyngeal and oropharyngeal swabbing. Patients with suspected acute UAI had symptoms and definitive diagnoses registered in a database. Trends in the number of referrals and patient encounters were retrieved from an electronic patient journal system and analyzed retrospectively. RESULTS: Eighty-eight patients with acute UAI were enrolled including 55 men and 34 women, median age of 31 years (range: 10 months to 82 years). One patient (1.1%) tested positive. Among 96 patients operated for HNC, zero tested positive. The number of referrals for HNC workup, and patient encounters for peritonsillar abscesses, decreased markedly in the first 3 weeks. CONCLUSION: The prevalence of SARS-CoV-2 during the first 6 weeks of the first wave was minimal among patients with acute UAI and zero among patients operated for HNC. The decrease in referrals for the workup of HNC may increase time to treatment initiation and patient morbidity.

Thiol-disulfide exchange between glutaredoxin and glutathione.

Glutaredoxins are ubiquitous thiol-disulfide oxidoreductases which catalyze the reduction of glutathione-protein mixed disulfides. Belonging to the thioredoxin family, they contain a conserved active site CXXC motif. The N-proximal active site cysteine can form a mixed disulfide with glutathione or an intramolecular disulfide with the C-proximal cysteine. The C-proximal cysteine is not known to be involved in the catalytic mechanism. The stability of the mixed disulfide with glutathione has been investigated in detail using a mutant variant of yeast glutaredoxin 1, in which the C-proximal active site cysteine has been replaced with serine. The exchange reaction between the reduced protein and oxidized glutathione leading to formation of the mixed disulfide could readily be monitored by isothermal titration calorimetry (ITC) due to the enthalpic contributions from the noncovalent interactions and the protonation of glutathione thiolate. An algorithm for the analysis of this type of reaction by ITC was developed and showed that the interaction is enthalpy driven with a large entropy penalty. The applicability of the method was verified by a mass spectrometry-based approach, which gave a standard reduction potential of -295 mV for the mixed disulfide. In another set of experiments, the pK(a) value of the active site cysteine was determined. In line with what has been observed for other glutaredoxins, this cysteine was found to have a very low pK(a) value. The glutathionylation of glutaredoxin was shown to have a substantial effect on the thermal stability of the protein as revealed by differential scanning calorimetry.