Seroprevalence of SARS-CoV-2 and humoral immune responses to COVID-19 mRNA vaccines among people who use drugs - in the light of tailored mitigating strategies.

BACKGROUND: During the initial wave of the COVID-19 pandemic, there was a surprisingly low incidence of SARS-CoV-2 among People Who Use Drugs (PWUD) in Oslo, Norway, despite their heightened vulnerability regarding risk of infection and severe courses of the disease.This study aims to investigate the seroprevalence of SARS-CoV-2 antibodies among PWUD, their antibody responses to relevant virus infections and COVID-19 mRNA vaccines, and their vaccination coverage compared to the general population. METHODS: Conducted as a prospective cohort study, data was collected from residents in six institutions for homeless PWUD and users of a low-threshold clinic for opioid agonist treatment. Ninety-seven participants were recruited for SARS-CoV-2 seroprevalence analysis. Additional two participants with known positive SARS-CoV-2 test results were recruited for further analyses. Twenty-five participants completed follow-up. Data included questionnaires, nasal swabs and blood samples. Data on vaccination coverage was obtained from the National Vaccine Register. Serologic methods included detection of antibodies to relevant virus proteins, neutralizing antibodies to SARS-CoV-2, antibodies to the full-length spike protein, and receptor-binding domain from SARS-CoV-2. RESULTS: Among PWUD, antibodies to SARS-CoV-2 were detected in 2 out of 97 samples before vaccines against SARS-CoV-2 were available, comparable to a 2.8% frequency in population-based screening. Levels of serum antibodies to seasonal coronaviruses and Epstein-Barr-Virus (EBV) in PWUD were similar to population-based levels. After the second vaccine dose, binding and neutralizing antibody levels to SARS-CoV-2 in PWUD were comparable to controls. Eighty-four of PWUD received at least one dose of COVID-19 mRNA vaccine, compared to 89% in the general population. CONCLUSION: Results indicate that PWUD did not exhibit increased SARS-CoV-2 seroprevalence or elevated serum antibodies to seasonal coronaviruses and EBV. Moreover, vaccine responses in PWUD were comparable to controls, suggesting that vaccination is effective in conferring protection against SARS-CoV-2 also in this population.

The LASSO Program in Oslo: Harm Reduction Using Buprenorphine-Naloxone (Suboxone®) in a Low Threshold Setting.

BACKGROUND: This is a 6-year retrospective quality control study of the LASSO Program (Low Threshold Substitution Treatment in Oslo), using exclusively Suboxone® (buprenorphine-naloxone [BPNX]) in out-patient settings. Adequate abstinence prior to induction is necessary to avoid acute onset opioid withdrawal symptoms; thus, its use in low threshold settings is far less common than methadone. OBJECTIVES: The aim of this study was to determine if BPNX is a safe and feasible medication to use in a low threshold setting. METHODS: The analysis is based on daily supervised BPNX medication. The standardized induction regime started with 4-mg BPNX increasing by 4 mg daily until 16 mg, with individual adjustments based on clinical status. Treatment effect was evaluated by the number of medication induction attempts, treatment length and lag time between initial contact and medication start. Statistical computations were performed with SPSS®. RESULTS: There were 331 out of 394 registered patient inquires that started on BPNX. Two hundred fifty-three patients (76.4%) completed induction on first attempt with 95% Wilson score CIs of (0.716-0.807). The accumulated percentage increased to 85.2% during successive inductions. No significant association was found between lag time and (i) the number of days on medication during the first induction; or (ii) total treatment length. Patients had a median lag time of 5 days, remained in treatment a median of 52.0 days with an average of 3.9 inductions. There were no cases of severe precipitated withdrawal and only 2 cases of adverse reactions among the 1,293 inductions and 25,544 administered dosages. CONCLUSION: This study shows that BPNX is highly effective in treating marginalized heroin addicts in low threshold settings. Even during their first attempt, 76.4% completed induction. There were no cases of severe precipitated withdrawal. Prolonged lag time affected neither the length of first treatment nor the total treatment length. Individualized induction readiness approach and motivation were central to the above results.

Urinary biomarkers in charcoal workers exposed to wood smoke in Bahia State, Brazil.

Charcoal is an important source of energy for domestic and industrial use in many countries. Brazil is the largest producer of charcoal in the world, with approximately 350,000 workers linked to the production and transportation of charcoal. To evaluate the occupational exposure to wood smoke and potential genotoxic effects on workers in charcoal production, we studied urinary mutagenicity in Salmonella YG1041 +S9 and urinary levels of 2-naphthol and 1-pyrenol in 154 workers of northeastern Bahia. Workers were classified into three categories according to their working location, and information about socio-demographic data, diet, alcohol consumption, and smoking was obtained using a standard questionnaire. Spot urine samples were collected to evaluate urinary mutagenicity and urinary metabolites. Urinary mutagenicity increased significantly with exposure to wood smoke and was modified by smoking. The prevalence odds ratio was 5.31, and the 95% confidence interval was 1.85; 15.27 for urinary mutagenicity in the highly exposed group relative to the nonexposed group. The levels of urinary metabolites increased monotonically with wood smoke exposure and were associated with the GSTM1 null genotype, which was determined previously. The prevalence odds ratio (95% confidence interval) for higher levels of 2-naphtol among the highly exposed was 17.13 (6.91; 42.44) and for 1-hydroxyprene 11.55 (5.32; 25.08) when compared with nonexposed workers. Urinary 2-naphthol was the most sensitive indicator of wood smoke exposure. This is the first reported measurement of internal exposure to wood smoke among charcoal workers, and the results showed that these workers receive a systemic exposure to genotoxic compounds.