Risk categorization and outcomes among healthcare workers exposed to COVID-19: A cohort study from a Thai tertiary-care center.

BACKGROUND: A risk categorization tool for healthcare workers (HCWs) exposed to COVID-19 is crucial for preventing COVID-19 transmission and requires validation and modification according to local context. METHODS: From January to December 2021, a prospective cohort study was conducted among Thai HCWs to evaluate the performance of the specifically-created risk categorization tool, which classified HCWs into low-risk (LR), intermediate-risk (IR), and high-risk (HR) groups based on types of activities, duration of exposure, and protective methods used during exposure. Subsequent measures were determined for the HCWs based on the risk categories. RESULTS: 1891 HCWs were included; 52%, 25% and 23% were LR, IR, and HR, respectively. COVID-19 was diagnosed in 1.3%, 5.1% and 27.3% of LR, IR and HR HCWs, respectively (P <0.001). Independent factors associated with COVID-19 were household or community exposure [adjusted odds ratio (aOR), 1588.68; P <0.001), being HR (aOR, 11.94; P <0.001), working at outpatient departments (aOR, 2.54; P <0.001), and no history of COVID-19 vaccination (aOR, 2.05; P = 0.01). The monthly rates of COVID-19 among LR, IR, and HR HCWs significantly decreased after the incremental rate of full vaccination. In-hospital transmission between HCWs occurred in 8% and was mainly due to eating at the same table. CONCLUSION: The study risk categorization tool can differentiate risks of COVID-19 among the HCWs. Prevention of COVID-19 should be focused on HCWs with the identified risk factors and behaviors associated with COVID-19 development and encouraging receipt of full vaccination.

An Open Label Randomized Controlled Trial of Ivermectin Plus Favipiravir-Based Standard of Care versus Favipiravir-Based Standard of Care for Treatment of Moderate COVID-19 in Thailand.

BACKGROUND: The role of ivermectin in the treatment of moderate coronavirus disease 2019 (COVID-19) is controversial. We performed an open label randomized controlled trial to evaluate the role of ivermectin plus favipiravir-based standard of care versus favipiravir-based standard of care for the treatment of moderate COVID-19 infection. MATERIALS AND METHODS: An open-label randomized control trial was performed at Thammasat Field Hospital and Thammasat University Hospital from October 1st, 2021 to May 31st, 2022. Patients with moderate COVID-19 infections were randomized to the intervention (ivermectin plus favipiravir-based standard of care) or control group (favipiravir-based standard of care alone). Patients were followed up to 21 days. The primary outcome was the improvement in World Health Organization (WHO) category ordinal scale by 2 points. Secondary outcomes included duration of illness, development of severe COVID-19, and adverse reactions. RESULTS: There were 157 patients in the intervention and 160 patients in the control group. Characteristics, underlying diseases, and risk factors for severe COVID-19 were comparable in both groups. Improvement in the WHO-category ordinal scale by 2 points was achieved in 98.7% of the intervention group and in 99.4% of the control group (relative risk [RR]: 0.487; 95% confidence interval [CI]: 0.044-5.430). The median illness duration was 5.0 days (range, 3 - 28 days) in intervention group versus 5.2 days (range, 3 - 28 days) in control group (P = 0.630). Severe COVID-19 that required intensive care occurred in 2 patients (1.3%) in the intervention group and 1 patient (0.6%) in the control group (RR: 2.052; 95% CI: 0.184 - 22.857). No significant difference in serious drug adverse events was seen. CONCLUSION: In this study ivermectin plus standard of care was not associated with improvement in the WHO-category ordinal scale, reduced illness duration, or development of severe COVID-19 in moderately ill COVID-19 patients. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: TCTR20220427005.