Since the first human case was reported in Wuhan Province, China in December 2019, SARS-CoV-2 has caused millions of human infections in more than 200 countries worldwide with an approximately 4.01% case-fatality rate (as of 27 July, 2020; based on a WHO situation report), and COVID-19 pandemic has paralyzed our global community. Even though a few candidate drugs, such as remdesivir (a broad antiviral prodrug) and hydroxychloroquine, have been investigated in human clinical trials, their therapeutic efficacy needs to be clarified further to be used to treat COVID-19 patients. Here we show that pyronaridine and artesunate, which are the chemical components of anti-malarial drug Pyramax®, exhibit antiviral activity against SARS-CoV-2 and influenza viruses. In human lung epithelial (Calu-3) cells, pyronaridine and artesunate were highly effective against SARS-CoV-2 while hydroxychloroquine did not show any effect at concentrations of less than 100 μM. In viral growth kinetics, both pyronaridine and artesunate inhibited the growth of SARS-CoV-2 and seasonal influenza A virus in Calu-3 cells. Taken together, we suggest that artesunate and pyronaridine might be effective drug candidates for use in human patients with COVID-19 and/or influenza, which may co-circulate during this coming winter season.

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Objective: To investigate the feasibility of using an ultraviolet light-emitting diode (UV LED) robot for the terminal decontamination of coronavirus disease 2019 (COVID-19) patient rooms. Methods: We assessed the presence of viral RNA in samples from environmental surfaces before and after UV LED irradiation in COVID-19 patient rooms after patient discharge. Results: This study analyzed 216 environmental samples from 17 rooms (two from airborne infection isolation rooms [AIIRs] in the intensive care unit [ICU] and 15 from isolation rooms in the community treatment center [CTC]). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was detected in 40 (18.5%) of 216 samples after patient discharge: 12 (33.3%) of 36 samples from AIIRs in the ICU, and 28 (15.6%) of 180 samples from isolation rooms in the CTC. In one AIIR, all samples were PCR-negative after UV LED irradiation. In the CTC rooms, 14 (8.6%) of the 163 samples were PCR-positive after UV LED irradiation. However, viable virus was not recovered from the culture of any of the PCR-positive samples. Conclusions: Although no viable virus was recovered, SARS-CoV-2 RNA was detected on various environmental surfaces. The use of a UV LED disinfection robot was effective in a spacious areas such as an ICU, but its effects varied in small spaces like CTC rooms. This suggests that the UV LED robot may need enough space to disinfect rooms without re-contamination by machine wheels or insufficient disinfection by shadowing.

Novel coronavirus (SARS-CoV-2) has caused more than 100 million confirmed cases of human infectious disease (COVID-19) since December 2019 to paralyze our global community. However, only limited access has been allowed to COVID-19 vaccines and antiviral treatment options. Here, we report the efficacy of the anticancer drug pralatrexate against SARS-CoV-2. In Vero and human lung epithelial Calu-3 cells, pralatrexate reduced viral RNA copies of SARS-CoV-2 without detectable cytotoxicity, and viral replication was successfully inhibited in a dose-dependent manner. In a time-to-addition assay, pralatrexate treatment at almost half a day after infection also exhibited inhibitory effects on the replication of SARS-CoV-2 in Calu-3 cells. Taken together, these results suggest the potential of pralatrexate as a drug repurposing COVID-19 remedy.

Purpose Neutralizing antibodies (NAbs) have been considered effective in preventing and treating viral infections. However, until now, the duration and clinical implications of antibody-mediated nature immunity in Koreans have remained unknown. Therefore, we examined NAbs levels and clinical characteristics in recovered coronavirus disease 2019 (COVID-19) patients. Materials and Methods Blood samples were collected from 143 adult patients who had been diagnosed with and had recovered from COVID-19 from February to March in 2020 at a tertiary-care university-affiliated hospital in Daegu, Korea. A plaque reduction neutralization test was conducted to analyze NAb titers. Individualized questionnaires were used to identify patient clinical information. Results The median number of days from symptom onset to the blood collection date was 109.0 (104.0; 115.0). The NAb titers ranged from 10 to 2560. The median NAb titer value was 40. Of the 143 patients, 68 (47.6%) patients had NAb titers ≥80, and 31 (21.7%) patients had NAb titers ≥160. The higher the age or disease severity, the higher the NAb titer. In univariate logistic regression, statistically significant predictors of high NAb titers (≥80) were age, myalgia, nausea or vomiting, dyspnea, and disease severity ( p <0.05). Multivariable logistic regression showed that age ≥50 years ( p =0.013) and moderate or higher disease severity ( p <0.001) were factors associated with high NAb titers (≥80). None of the patients had reinfection of COVID-19. Conclusion All recovered patients were found to have NAbs regardless of the NAb titers maintained by natural immunity. Age and disease severity during COVID-19 infection were associated with high NAb titers.