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.

1893. 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 severe acute respiratory syndrome coronavirus-2 is crucial for preventing coronavirus disease 2019 (COVID-19) transmission and requires validation and modification according to local context. We conducted this study to evaluate the performance of the study risk categorization tool and COVID-19-related outcomes among HCWs.

Methods

From 1 January to 31 December 2021, a prospective cohort study was conducted among COVID-19 exposing HCWs at a Thai tertiary-care center. The study risk categorization tool was specifically created in this study and modified from the United States Centers for Disease Control and Prevention recommendations, 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. The primary outcome was the difference in rates of COVID-19 in the LR, IR and HR HCWs.

Results

There were 1,892 HCWs included; 52%, 25% and 23% were LR, IR, and HR, respectively. The median age was 30 years (IQR, 26-36 years). The majority was female (79%) and nurses (33%). The most common risk activities were being in the same room with closed space without wearing a mask with COVID-19 cases (75%). COVID-19 was diagnosed in 157 HCWs and 27%, 5% and 1% of HR, IR and LR HCWs, respectively (P&lt; 0.001). By multivariable analysis, factors associated with COVID-19 included household or community exposure [adjusted odds ratio (aOR), 1588.68; P&lt; 0.001], being HR group (aOR, 11.94; P&lt; 0.001), working at outpatient departments (aOR, 2.54; P&lt; 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 (58%).

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.

Disclosures

All Authors: No reported disclosures.

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.