key: cord-0853208-dunk81n0
authors: Delandre, Océane; Gendrot, Mathieu; Jardot, Priscilla; Le Bideau, Marion; Boxberger, Manon; Boschi, Céline; Fonta, Isabelle; Mosnier, Joel; Hutter, Sébastien; Levasseur, Anthony; La Scola, Bernard; Pradines, Bruno
title: Antiviral Activity of Repurposing Ivermectin against a Panel of 30 Clinical SARS-CoV-2 Strains Belonging to 14 Variants
date: 2022-04-02
journal: Pharmaceuticals (Basel)
DOI: 10.3390/ph15040445
sha: a26221d35f370e479fb09a29eb5e4dbba4ba051f
doc_id: 853208
cord_uid: dunk81n0

Over the past two years, several variants of SARS-CoV-2 have emerged and spread all over the world. However, infectivity, clinical severity, re-infection, virulence, transmissibility, vaccine responses and escape, and epidemiological aspects have differed between SARS-CoV-2 variants. Currently, very few treatments are recommended against SARS-CoV-2. Identification of effective drugs among repurposing FDA-approved drugs is a rapid, efficient and low-cost strategy against SARS-CoV-2. One of those drugs is ivermectin. Ivermectin is an antihelminthic agent that previously showed in vitro effects against a SARS-CoV-2 isolate (Australia/VI01/2020 isolate) with an IC(50) of around 2 µM. We evaluated the in vitro activity of ivermectin on Vero E6 cells infected with 30 clinically isolated SARS-CoV-2 strains belonging to 14 different variants, and particularly 17 strains belonging to six variants of concern (VOC) (variants related to Wuhan, alpha, beta, gamma, delta and omicron). The in vitro activity of ivermectin was compared to those of chloroquine and remdesivir. Unlike chloroquine (EC(50) from 4.3 ± 2.5 to 29.3 ± 5.2 µM) or remdesivir (EC(50) from 0.4 ± 0.3 to 25.2 ± 9.4 µM), ivermectin showed a relatively homogeneous in vitro activity against SARS-CoV-2 regardless of the strains or variants (EC(50) from 5.1 ± 0.5 to 6.7 ± 0.4 µM), except for one omicron strain (EC(50) = 1.3 ± 0.5 µM). Ivermectin (No. EC(50) = 219, mean EC(50) = 5.7 ± 1.0 µM) was, overall, more potent in vitro than chloroquine (No. EC(50) = 214, mean EC(50) = 16.1 ± 9.0 µM) (p = 1.3 × 10(−34)) and remdesivir (No. EC(50) = 201, mean EC(50) = 11.9 ± 10.0 µM) (p = 1.6 × 10(−13)). These results should be interpreted with caution regarding the potential use of ivermectin in SARS-CoV-2-infected patients: it is difficult to translate in vitro study results into actual clinical treatment in patients.

In December 2019, a new disease called coronavirus disease 2019 , caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), began to spread all over the world [1] . Over the past two years, several emerging variants of SARS-CoV- 2 

The EC 50 means of ivermectin for the 30 clinically isolated SARS-CoV-2 strains ranged from 1.3 ± 0.5 to 6.7 ± 0.4 µM (Table 1 ). There was no significant difference regarding ivermectin activity within a variant (related to Wuhan, Marseille-1, Marseille-4, alpha or delta) regardless of the strain tested (p from 0.09 to 0.29, Kruskal-Wallis rank sum test) ( Table 1) . Only the omicron variant showed a significant different susceptibility between the different strains (EC 50 means ranged from 1.3 ± 0.5 to 6.7 ± 0.4 µM, p = 0.003). There was a significant difference between the variants analysed (p = 0.0002, Kruskal-Wallis rank sum test) ( Figure 1 ). Table 1 . In vitro susceptibility of different clinically isolated SARS-CoV-2 variants of concern or interest to ivermectin.

Origin Strain Name EC 50 in µM (Mean ± SD a ) Variant EC 50 The EC50 means of chloroquine, used for comparison, for the 30 clinically isolated SARS-CoV-2 strains ranged from 4.3 ± 2.5 to 33.7 ± 9.0 μM ( Table 2) .

There was no significant difference in chloroquine activity within a variant (related to Wuhan, Marseille-1, Marseille-4, alpha, delta or omicron) regardless of the strains tested (p from 0.06 to 0.82, Kruskal-Wallis rank sum test) ( Table 2 ). However, there was a significant difference between the different variants analysed (p = 1.4 × 10 −22 , Kruskal-Wallis rank sum test). The alpha and omicron variants were the most susceptible (p = 1.7 × 10 −5 and 2.7 × 10 −5 , respectively, compared to the original Wuhan variant) ( Figure 2 ). There was no significant difference in chloroquine susceptibility between the omicron and alpha variants (p = 0.69). The EC 50 means of chloroquine, used for comparison, for the 30 clinically isolated SARS-CoV-2 strains ranged from 4.3 ± 2.5 to 33.7 ± 9.0 µM ( Table 2) .

There was no significant difference in chloroquine activity within a variant (related to Wuhan, Marseille-1, Marseille-4, alpha, delta or omicron) regardless of the strains tested (p from 0.06 to 0.82, Kruskal-Wallis rank sum test) ( Table 2 ). However, there was a significant difference between the different variants analysed (p = 1.4 × 10 −22 , Kruskal-Wallis rank sum test). The alpha and omicron variants were the most susceptible (p = 1.7 × 10 −5 and 2.7 × 10 −5 , respectively, compared to the original Wuhan variant) ( Figure 2 ). There was no significant difference in chloroquine susceptibility between the omicron and alpha variants (p = 0.69). The EC50 means of remdesivir, used for comparison, for the 30 clinically isolated SARS-CoV-2 strains ranged from 0.4 ± 0.3 to 25.9 ± 7.4 μM (Table 3) . IHU-MI-2615 11.7 ± 8.8 11.7 ± 8.8 The EC 50 means of remdesivir, used for comparison, for the 30 clinically isolated SARS-CoV-2 strains ranged from 0.4 ± 0.3 to 25.9 ± 7.4 µM (Table 3) .

There was no significant difference in remdesivir activity within a variant (related to Wuhan, Marseille-1, Marseille-4, alpha or delta) regardless of the strains tested (p from 0.08 to 0.94, Kruskal-Wallis rank sum test) ( Table 3) . Only the omicron variant showed significant susceptibilities between the different strains (EC 50 means ranged from 0.4 ± 0.3 to 1.3 ± 0.1 µM, p = 0.006). There was a significant difference between the different variants analysed (p = 2.0 × 10 −21 , Kruskal-Wallis rank sum test). The omicron variant was the most susceptible to remdesivir (p = 0.003, omicron variant versus alpha variant) followed by the alpha variant (p = 0.01, alpha variant versus variant related to Wuhan) and by the variant related to Wuhan (p = 0.03, alpha variant versus Marseille-9 variant) ( Figure 3 ). Table 3 . In vitro susceptibility of different clinically isolated SARS-CoV-2 variants of concern or interest to remdesivir.

Origin Strain Name EC 50 There was no significant difference in remdesivir activity within a variant (related to Wuhan, Marseille-1, Marseille-4, alpha or delta) regardless of the strains tested (p from 0.08 to 0.94, Kruskal-Wallis rank sum test) ( Table 3) . Only the omicron variant showed significant susceptibilities between the different strains (EC50 means ranged from 0.4 ± 0. 

Although the 14 SARS-CoV-2 variants showed a significant variation of in vitro susceptibility to ivermectin (from 4.8 to 6.2 µM, p = 0.0002), these were relatively homogeneous (from 5.1 ± 0.5 to 6.7 ± 0.4 µM) if the susceptibility of the IHU-MI-5227 omicron strain is removed. Indeed, this strain presented a higher susceptibility to ivermectin than the other 29 strains (1.3 ± 0.5 µM). These results were consistent with the previous data by Caly et al. (IC 50 = 2.8 µM) [26] . Ivermectin was potent in vitro against SARS-CoV-2, regardless of the strains and the variants. Ivermectin (No. EC 50 = 219, mean EC 50 = 5.7 ± 1.0 µM) was more potent in vitro overall than chloroquine (No. EC 50 = 214, mean EC 50 = 16.1 ± 9.0 µM) (p = 1.3 × 10 −34 , Welch t-test) and remdesivir (No. EC 50 = 201, mean EC 50 = 11.9 ± 10.0 µM) (p = 1.6 × 10 −13 , Welch t-test).

Several modes of action were suggested for ivermectin [38] . Host proteins, such as STAT transcription factors, interact with the importin heterodimer complex (IMPα/β1) by binding the IMPα in cytoplasm and are transported into the nucleus using the nuclear pore complex (NPC) located in the nuclear envelope [39] . Many viruses interact with IMPα/β1 to access into the nucleus through the NPC [40] . Ivermectin has been found to reduce West Nile, dengue, HIV-1 and influenza A viral replication by inhibiting nuclear import via IMPα/β1 [41] [42] [43] [44] . It was suggested that ivermectin also decreases SARS-CoV-2 replication by inhibiting IMPα/β1-mediated nuclear transport [26] . In silico molecular docking reports interaction between ivermectin and IPMα [45] [46] [47] . Another hypothesis is the inhibition of the viral RNA-dependent RNA polymerase (RdRp, replicase) which is essential for viral genome replication. A strong interaction between ivermectin and SARS-CoV-2 RdRp has been demonstrated by the in silico approach [48] [49] [50] [51] . In some studies, ivermectin showed higher binding affinity to the predicted active RdRp than remdesivir [48] [49] [50] , which is known to inhibit viral replication and RdRp [52, 53] . Another replicase, named 3 chymotrypsin-like protease (3CLpro) or main protease (Mpro) is crucial in SARS-CoV-2 replication, leading to the formation of non-structural proteins (NSPs) [54] . Ivermectin has been found to have a strong interaction with 3C-like protease [46, 47, 49, 51, 55, 56] . Ivermectin could also inhibit SARS-CoV-2 cell entry by linking itself to the SARS-CoV-2 viral spike glycoprotein receptor-binding domain (RBD) and the angiotensin-converting enzyme-2 (ACE2) transmembrane receptor protein [45, 46, 57, 58] . Moreover, SARS-CoV-2 requires the transmembrane protease serine 2 (TMPPRSS2) in order to activate the spike protein. This protein can also be a potential target for ivermectin [48, 51] .

Unlike ivermectin, which showed relatively homogeneous in vitro activity against SARS-CoV-2 regardless of the strain or variant, variant susceptibility to chloroquine was heterogeneous. Omicron and alpha variants were the most susceptible to chloroquine. The strains related to Wuhan were less susceptible than strains belonging to the omicron and alpha variants but were more susceptible than strains belonging to the beta, gamma and delta variants. Chloroquine can inhibit in silico viral entry into the host cell by interacting with sialic acids linked to gangliosides on host cellular surface and ACE receptor [59] [60] [61] [62] [63] . In the presence of chloroquine, the viral spike protein is no longer able to link gangliosides [59] . Chloroquine also interacts with the TMPRSS2 protein [51, 64, 65] . The replicase 3CLpro may also be a potential target for chloroquine [51, 55, 66, 67] .

The emergence of mutations in the spike glycoprotein of SARS-CoV-2 might impact drug efficacy, and more particularly chloroquine efficacy. As compared to the spike protein relative to the Wuhan sequences, the different variants include few non-synonymous mutations except the omicron variant which contains 30 mutations. The different mutations for each variant are reported in Supplementary Table S1 . The significant polymorphism of the omicron spike protein would suggest changes in protein structure and a decrease in chloroquine in vitro activity. Conversely, the omicron variant is one of the two most susceptible variants. Recently, it has been shown that omicron enters cells mainly by TMPRSS2-independent fusion following endocytosis after processing by cathepsin B or L, while the other variants enter by fusion following proteolytic processing by TMPPRSS2 [68] . Chloroquine is a weak base compound, referred to as lysosomotropic drug, which accumulates in endosomes and lysosomes, and increased lysosomal pH leading to a decrease in lysosomal protease activities and, finally, prevents viral entry into host cells [69, 70] . Chloroquine also inhibits viral replication due to the lack of enzyme functional activities at a high pH [71] . The elevated pH in endosomes by chloroquine could explain the in vitro activity against the omicron variant.

In vitro susceptibility to remdesivir also varied. The three omicron, alpha and Wuhanrelated variants were the most susceptible variants. In vitro remdesivir shows a broad spectrum of antiviral activity against RNA viruses by targeting replicase such as RdRp [52, 72] . Remdesivir can also inhibit the SARS-CoV-2 RdRp [51, 53, [73] [74] [75] . Remdesivir can also dock the 3CLpro replicase [49, 51, 76, 77] . These results are consistent with in vitro data demonstrating that it inhibits SARS-CoV-2 viral replication only at the post-entry stage in Vero E6 cells and not at the entry stage [21] .

However, these results must be interpreted with caution regarding the potential use of ivermectin in SARS-CoV-2-infected patients: it is difficult to translate in vitro study results into actual clinical treatment in patients. First, it is crucial to determine whether the concentrations required are consistent with concentrations observed in humans. Ninetythree percent of ivermectin is bound to plasma proteins and there is no data on penetration and concentration of ivermectin into human lungs [78] . Modelling the FDA-approved dose of 200 µg/kg or single oral dose of 120 mg leads to insufficient concentrations in plasma or lung tissue to achieve around 5 µM [79] [80] [81] . After a single dose of ivermectin 200 µg/kg, lung concentrations are predicted to be around a quarter of an IC 50 of around 2.0 µM [82] . Another model, considering host viral kinetics of SARS-CoV-2, pharmacodynamic effects and the pharmacokinetic profile of ivermectin, shows that ivermectin at 600 µg/kg three times a day in a patient weighing 70 kg has similar effects to the maximal oral dose of 120 mg and significantly reduced SARS-CoV-2 viral load [82] . Moreover, Arshad et al. predicted ivermectin accumulation in lung tissue over 20 times higher than EC 50 [83] .

Ivermectin antiviral activity can be improved by combinations with antiviral agents with differing modes of action and new pharmaceutical formulations that can more efficiently deliver ivermectin at high concentrations in the lung tissue. The in vitro combination of ivermectin (2 µM) and remdesivir (6 µM) shows highly synergistic effects against the murine hepatitis virus (MHV), which belongs to the betacoronavirus genus like the SARS-CoV-2 [25] . Ivermectin exerts higher in vitro inhibition of importin α nuclear accumulation in combination with atorvastatin than when used alone [84] . A randomised, blind trial in patients with mild-to-moderate COVID-19 symptoms showed that patients treated with ivermectin 12 mg and doxycycline 100 mg, twice a day for five days, recovered earlier than those receiving standard care alone (paracetamol, antihistaminics, vitamins, low molecular weight heparin and oxygen therapy if necessary), and were more significantly asymptomatic after 12 days and were less likely to be diagnosed with SARS-CoV-2 after 14 days [85] . However, the viral load was not estimated and the efficacy of ivermectin or doxycycline used alone was not evaluated. Another pilot clinical trial in patients with mild-to-moderate COVID-19 symptoms showed that patients who received a single dose of ivermectin 200 µg/kg at the day of admission in combination with hydroxychloroquine (400 mg twice a day for the first day and 200 mg twice a day for five days) associated with azithromycin (500 mg the first day and 250 mg for five days) were cured faster and had a shorter stay in hospital in comparison with patients who received only hydroxychloroquine in combination with azithromycin [86] . However, these results must be interpreted with caution given the small sample size and because this study was not randomised.

The administration of ivermectin by inhalation could be a way to achieve its accumulation into the lungs. The administration of nebulised ivermectin at 116.5 mg/kg in rats led to plasma concentrations of 186.7 ng/mL (0.21 µM) 24h after administration and 524.3 ng/g in lung tissue 168 h after administration [87] . In piglets, after the administration of one dose of 2 mg of ivermectin by nasal spray, a significant positive correlation was reported between the ivermectin concentrations in nasopharyngeal and lung tissues [88] . Ivermectin concentrations in nasopharyngeal tissue may be higher with an intranasal dose of ivermectin 2 mg twice a day than a single oral dose of 0.2 mg/kg (12 mg) for a person weighing 60 kg.

The clinical efficacy of ivermectin in COVID-19 treatments remains controversial. In one retrospective study, a single standard dose of 200 µg/kg of ivermectin did not significantly reduce the duration of the SARS-CoV-2 detection and did not improve clinical outcomes in severe COVID-19 patients [89] . However, no difference was found in baseline characteristics, clinical presentation, use of associated treatment (such as hydroxychloroquine, azithromycin, lopinavir, ritonavir, remdesivir, tocilizumab or beta-interferon) and outcomes between patients treated with and without ivermectin. Moreover, a daily dose of 14 mg of ivermectin for four days did not significantly reduce the need for admission to an intensive care unit, the use of invasive ventilation or the occurrence of death in patients hospitalised with severe COVID-19, in comparison with treatment with hydroxychloroquine (400 mg daily for five days) [90] . Unfortunately, the efficacy of ivermectin was not compared against a placebo. There was no difference in RT-PCR negativity on day 6 between patients who received a daily dose of 12 mg of ivermectin for two days compared to patients who did not receive ivermectin treatment [91] . However, a daily dose of 12 mg of ivermectin for two days significantly prevented mortality (100% of patients were successfully discharged compared to 93%). In another randomised, double-blind, placebo-controlled trial (IVERCOR-COVID-19) using the same regimen, ivermectin administration did not improve RT-PCR on days 3 and 7 and did not prevent hospitalisation [92] . A five-day course of 300 µg/kg of ivermectin per day (compared to a placebo) did not significantly improve the time of recovery from symptoms (10 days compared to 12 days) [93] . In a pilot, double blind, randomised controlled trial in hospitalised patients with mild-tomoderate manifestations of COVID-19, a single oral administration of ivermectin of either 12 or 24 mg did not significantly reduce the viral load on day 5 or negate the presence of SARS-CoV-2 in comparison with a placebo, although RT-PCR negativity was higher but not significant in the group of patients who received 24 mg (47.5%) than those who received a placebo (31.1%) [94] . Oral ivermectin used at 400 µg/kg body weight daily for five days in addition to standard clinical care did not prevent progression to severe disease among high-risk patients with mild to moderate COVID-19 in comparison with patients who received only standard care (21.6% versus 17.3%) [95] . The use of a single dose of 12 mg of ivermectin in combination with azithromycin, montelukast (a cysteinyl leukotriene receptor antagonist) and acetylsalicylic acid improved recovery and prevented the risk of hospitalisation and death in COVID-19 out-patients compared to the placebo group [96] . However, the patients who received ivermectin had a significantly lower prevalence of comorbidities and were younger than the comparison group. Moreover, it is difficult to evaluate the role of ivermectin in the efficacy of the combination. In another randomised, double-blind, placebo-controlled pilot trial in patients with non-severe manifestations of COVID-19 and no risk factors for complicated disease, individuals treated with a single dose of 400 µg/kg of ivermectin had lower but not significantly lower viral loads on day 4 and day 7 post-treatment [97] . Patients treated with ivermectin recovered earlier from hyposmia, anosmia and a cough. Patients who received two doses of 200 µg/kg of ivermectin in addition to standard clinical care stayed in intensive care for a significantly shorter time (three days versus 18 days) and required a shorter duration of mechanical ventilation (three days versus 18 days) than the control group who received only standard clinical care [98] . A reduction of 11.2% in the risk of death was reported in hospitalised patients treated with a single oral dose of 200 µg/kg of ivermectin in addition to standard clinical care, compared with patients only treated with standard clinical care [99] . Most of the clinical studies previously cited were reanalysed to assess their risk of bias including randomisation, blinding, attrition or estimation of effects and were classified as studies with a low risk of bias [100, 101] . Most of the previous publications or systematic reviews concluding that there were significant benefits of the use of ivermectin were based on potentially biased results due to methodological limitations [101, 102] . Further stringent research is needed. The strains were maintained in production in Vero E6 cells (American type culture collection ATCC ® CRL-1586™) in MEM with 4% foetal bovine serum and 1% glutamine (complete medium). Vero E6 cells are one of the most widely used cells for the culture of SARS-CoV-2 due to the presence of the high expression of angiotensin converting enzyme 2 (ACE2) receptors, essential for SARS-CoV-2 cell entry [108, 109] . Vero E6 cells were found to be relevant for antiviral drug screening models [17, 109] .

Briefly, 96-well plates were prepared with 5 × 10 5 cells/mL of Vero E6 (200 µL per well), as previously described [10] . The different concentrations of ivermectin, chloroquine or remdesivir were added 4 h before infection. The replication of the different strains in Vero E6 cells at an MOI of 0.01 was estimated 48 h after infection by RT-PCR using the Superscript III platinum one step with Rox kit (Invitrogene, Villebon sur Yvette, France) after RNA extraction using the QIAamp 96 Virus QIAcube HT Kit (QIAGEN, Hilden, Germany) on the QIAcube HT System (QIAGEN, Hilden, Germany). The primers used were previously described [110] . The percentage of inhibition of SARS-CoV-2 replication was estimated for each drug concentration as follows: (mean CT drug concentration − mean CT control 0% )/(mean CT control 100% − mean CT control 0% ) × 100. The CT control 0% (0% of inhibition) corresponds to the mean of 12 CT of SARS-CoV-2 replication in the absence of drug 48 h after infection. The CT control 100% (100% of inhibition) corresponds to the mean of 12 CT of SARS-CoV-2 after 48 h of Vero E6 cells infection in the presence of high concentrations of drug. This CT control 0% is similar to the CT of virus inoculum used to infect Vero E6 cells at 0 h. EC 50 (median effective concentration) values were estimated through nonlinear regression using the R software (ICEstimator version 1.2). EC 50 values resulted in the mean of 5 to 11 independent experiments.

The in vitro evaluation of ivermectin has been described in only one paper using only one SARS-CoV-2 isolate (Australia/VI01/2020 isolate) [26] . In the present work, we proposed to compare the in vitro activity of ivermectin first between various isolates belonging to the same variant and then between various variants (and more particularly variants related to Wuhan, alpha, beta, gamma, delta and omicron). Unlike chloroquine or remdesivir, ivermectin showed a relatively homogeneous in vitro activity against SARS-CoV-2 (4.8 to 6.2 µM) regardless of the strain or variant of concern (Wuhan, alpha, beta, gamma, delta or omicron). These results must be interpreted with caution regarding the potential use of ivermectin in SARS-CoV-2-infected patients: it is difficult to translate in vitro study results into actual clinical treatment in patients. The expected ivermectin concentration levels in human lungs after standard doses remain controversial, as well as its efficacy in patients with COVID-19. Ivermectin antiviral activity can be improved by combinations with antiviral agents with differing modes of action and new pharmaceutical formulations that can more efficiently deliver ivermectin at high concentrations into the lung tissue (through inhalation, for instance). Further stringent research, particularly clinical trials, is needed to investigate ivermectin as COVID-19 treatment.

Supplementary Materials: The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/ph15040445/s1, Table S1 : List of nucleotide and amino acid changes associated with the different SARS-CoV-2 variants. Informed Consent Statement: Informed consent was not required for this study. Isolates were anonymised by re-coding. Additionally, bio-banking of human clinical samples used for diagnostics and secondary uses for scientific purposes is possible as long as the corresponding patients are informed and have not indicated any objections.

The analysed data presented in this study are available on the main text and the raw data are available on request from the corresponding author. The raw data are not publicly available due to due to archiving on a military server.

A new coronavirus associated with human respiratory disease in China

Evolutionary trajectory of SARS-CoV-2 and emerging variants

The emerging SARS-CoV-2 variants of concern

SARS-CoV-2 vaccines: Where are we now?

SARS-CoV-2 (COVID-19) vaccines structure, mechanisms and effectiveness: A review

Antimalarial drugs inhibit the replication of SARS-CoV-2: An in vitro evaluation

Antimalarial artemisinin-based combination therapies (ACT) and COVID-19 in Africa: In vitro inhibition of SARS-CoV-2 replication by mefloquine-artesunate

Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCov) in vitro

Identification of an antiviral compound from the pandemic response box that efficiently inhibits SARS-CoV-2 infection in vitro

In vitro testing of hydroxychloroquine and azithromycin on SARS-CoV-2 shows synergistic effect

vitro antiviral activity of doxycycline against SARS-CoV-2. Molecules

Remdesivir, lopinavir, emetine, and homoharringtonine inhibit SARS-CoV-2 replication in vitro

Comparative antiviral efficacy of viral protease inhibitors against the novel SARS-CoV-2 in vitro

Clofazimine broadly inhibits coronaviruses including SARS-CoV-2

Broad anticoronavirus activity of Food and Drug Administration-approved drugs against SARS-CoV-2 in vitro and SARS-CoV in vivo

Drug repurposing screen identifies masitinib as a 3CLpro inhibitor that blocks replication of SARS-CoV-2 in vitro

Drug repurposing screens reveal cell-type-specific entry and FDA-approved drugs active against SARS-CoV-2

Antiviral activities of mycophenolic acid and IMD-0354 against SARS-CoV-2

Comparative analysis of antiviral efficacy of FDA-approved drugs against SARS-CoV-2 in human lung cells

Methylene blue inhibits replication of SARS-CoV-2 in vitro

In vitro evaluation of the antiviral activity of methylene blue alone or in combination against SARS-CoV-2

Orally administered bismuth drug together with N-acetyl cysteine as a broad-spectrum anti-coronavirus therapy

Ivermectin: A systematic review from antiviral effects to COVID-19 complementary regimen

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Clinical outcomes in COVID-19 patients infected with different SARS-CoV-2 variants in Marseille

Does SARS-CoV-2 re-infection depend on virus variant?

SARS-CoV-2 infectivity and severity of COVID-19 according to SARS-CoV-2 variants: Current evidence

Neutralizing activity of Sputnik V vaccine sera against SARS-CoV-2 variants

Progress of the COVID-19 vaccine effort: Viruses, vaccines and variants versus efficacy, effectiveness and escape

Correlates of SARS-CoV-2 variants on death, case incidence and case fatality ratio among the continents for the period of 1

Comparison of neutralizing antibody titers elicited by mRNA and adenoviral vector vaccine against SARS-CoV-2 variants

High individual heterogeneity of neutralizing activities against the original strain and nine different variants of SARS-CoV-2. Viruses

The puzzling mutational landscape of the SARS-2-variant Omicron

Emerging SARS-CoV-2 genotypes show different replication patterns in human pulmonary and intestnal epithelial cells

Considerable escape of SARS-CoV-2 Omicron to antibody neutralization

The mechanisms of action against SARS-CoV-2: An evidence-based clinical review article

Nuclear trafficking of proteins from RNA viruses: Potential target for antivirals

Inhibitors of nuclear transport

Ivermectin is a specific inhibitor of importin α/β-mediated nuclear import able to inhibit replication of HIV-1 and dengue virus

The broad spectrum antiviral ivermectin targets the host nuclear transport importin α/β1 heterodimer

Repositioning ivermectin for COVID-19 treatment: Molecular mechanisms of action against SARS-CoV-2 replication

An in-silico analysis of ivermectin interaction with potential SARS-CoV-2 targets and host nuclear importin α

Elucidation of the inhibitory activity of ivermectin with host nuclear importin α and several SARS-CoV-2 targets

Comparative study of the interaction of ivermectin with proteins of interest associated with SARS-CoV-2: A computational and biophysical approach

Exploring the binding efficacy of ivermectin against the key proteins of SARS-CoV-2 pathogenesis: An in silico approach

In silico studies of selected multi-drug targeting against 3CLpro and nsp12 RNA-dependent RNA-polymerase proteins of SARS-CoV-2 and SARS-CoV

Prediction of potential inhibitors for RNA-dependent RNA polymerase of SARS-CoV-2 using comprehensive drug repurposing and molecular docking approach

Abdel-Moneim, A.S. Molecular docking reveals ivermectin and remdesivir as potential repurposed drugs against SARS-CoV-2. Front. Microbiol. 2021, 11, 592908

Therapeutic efficacy of the small molecule GS-5734 against Ebola virus in rhesus monkeys

Remdesivir is a direct-acting antiviral that inhibits RNA-dependent RNA polymerase from severe acute respiratory syndrome coronavirus 2 with high potency

Drug repurposing for candidate SARS-CoV-2 main protease inhibitors by a novel in silico methods

Identification of 3-chymothrypsin like protease (3CLpro) inhibitors as potentail anti-SARS-CoV-2 agents

Computational investigations of three main drugs and their comparison with synthesized compounds as potent inhibitors of SARS-CoV-2 main protease (Mpro): DFT, QSAR, molecular docking, and in silico toxicity analysis

Ivermectin docks to the SARS-CoV-2 spike receptor-binding domain attached to ACE

The binding mechanism of ivermectin and levosalbutamol with spike protein of SARS-CoV-2

Structural and molecular modelling studies reveal a new mechanism of action of chloroquine and hydroxychloroquine against SARS-CoV-2 infection

Inhibitory capacity of chloroquine against SARS-CoV-2 by effective binding with angiotensin converting enzyme-2 receptor: An insight from molecular docking and MD-simulation studies

Computational and experimental insights on the interaction of artemisinin, dihydroartemisinin and chloroquine with SARS-CoV-2 spike prtein receptor-binding domain (RBD)

Molecular modeling of the interaction of ligands with ACE2-SARS-CoV-2 spike protein complex

Design and synthesis of heteroclic azole based bioactive compounds: Molecular structures, quantum simulation, and mechanistic studies through docking as multi-target inhibitors of QARS-CoV-2 and cytotoxicity

Computational studies reveal Fluorine based quinilines to be potent inhibitors for proteins involved in SARS-CoV-2 assembly

The application of in silico experimental model in the assessement of ciprofloxacin and levofloxacin interaction with man SARS-CoV-2 targets: S-, E-and TMPRSS2 proteins, RNA-dependent RNA polymerase and papain-like protease (PLpro)-Preliminary molecular docking analysis

Sreening and evaluation of approved drugs as inhibitors of main protease of SARS-CoV-2

In silico study of azithromycin, chloroquine and hydroxychloroquine and their potential mechanisms of action against SARS-CoV-2 infection

The hyper-transmissible SARS-CoV-2 Omicron variant exhibite significant antigenic change, vaccine escape and a switch in cell entry mechanism

Chloroquine and hydroxychloroquine as available weapons to fight COVID-19

New insights on the antiviral effects of chloroquine against coronavirus: What to expect for COVID-19

Chloroquine to fight COVID-19: A consideration of mechanisms and adverse effects? Heliyon 2020, 6, e04900

Broad spectrum antiviral remdesivir inhibits human endemic and zoonotic deltacoronavirus with a highly divergent RNA dependent RNA polymerase

Polyphenols as potential inhibitors of SARS-CoV-2 RNA dependent RNA polymerase (RdRp)

Comparative assessement of favipiravir and remdesivir againt human coronavirus NL63 in molecular docking and cell culture lodels

The anti-HCV, Sofosbuvir, versus the anti-EBOV Remdesivir against SARS-CoV-2 RNA dependent RNA polymerase in silico

In silico molecular docking analysis for repurposing therapeutics against multiple proteins from SARS-CoV-2

Ligand-based quantitative structural assessements of SARS-CoV-2 3CLpro inhibitors: An analysis in light of structure-based multi-molecular modeling evidences

The effect of protein binding on ivermectin uptake by bovine brain microvessel endothelial cell

Pharmacokinetic considerations on the repurposing of ivermectin for treatment of COVID-19

Development of a minimal physiologically-based pharmacokinetic model to simulate lung exposure in humans following oral administration of ivermectin for COVID-19 drug repurposing

The approved dose of ivermectin alone is not the ideal dose for the treatment of COVID-19

Modeling of SARS-CoV-2 treatment effects for informed drug repurposing

priorisation of anti-SARS-CoV-2 drug repurposing opportunities based on plasma and target site concentrations derived from their established human pharmacokinetics

Effect of ivermectin and atorvastatin on nuclear localization of importin Alpha and drug target expression profiling in host cells from nasopharyngeal swabs of SARS-CoV-2-positive patients

Ivermectin in combination with doxycycline for treating COVID-19 symptoms: A randomized trial

Effectiveness of Ivermectin as add-on therapy in COVID-19 management

Nebulized ivermectin for COVID-19 and other respiratory diseases, a proof of concept, does-ranging study in rats

Safety and phramacokinetic assessments of a novel ivermectin nasal spray formulation in a pig model

Lack of efficacy of stanadrd doses of ivermectin in severe COVID-19 patients

Phase 2 randomized study on chloroquine, hydroxychloroquine or ivermectin in hospitalized patients with severe manifestations of SARS-CoV-2 infection

Ivermectin as a potential treatment for mild to moderate COVID-19-A double blind randomized placebo-controlled trial. medRxiv 2021

Ivermectin to prevent hospitalizations in patients with COVD-19 (IVERCOR-COVID19) a randomized, double-blind, placebo-controlled trial

Effect if ivermectin on time to resolution of symptoms among adults with mild COVID-19

Single-dose oral ivermectin in mild and moderate COVID-19 (RIVET-COV): A single-centre randomized, placebo-controlled trial

Efficacy of ivermectin treatment on disease progression among adults with mild to moderate COVID-19 and comorbidities: The I-TECH randomized clinical trial

Effectiveness of multidrug therapy consisting of Ivermectin, Azithromycin, Montelukast, and Acethylsalicylic acid to prevent hospitalization and death among ambulatory COVID-19 cases in Tlaxcala

The effect of eraly treatment with ivermectin on viral load, symptoms and humoral response in patients with non-severe COVID-19: A pilot, doule-blind, placebo-controlled

Effectiveness and safety of ivermectin in COVID-19 patients: A prospecive study at a safetynet hospital

Use of ivermectin is associated with lower mortality in hospitalized patients with coronavirus disease

Ivermectin for COVID-19: Adressing potential bias and medical fraud

Bias as a source of inconsistency in ivermectin trials for COVID-19: A systematic review. Ivermectin's suggested benefits are mainly based on potentially biased results

Meta-analysis of randomized trials of ivermectin to treat SARS-CoV-2 infection

Clinical outcomes in patients infected with different SARS-CoV-2 variants at one hospital during three phases of the COVID-19 epidemic in Marseille

Introduction into the Marseille geographical area of a mild SARS-CoV-2 variant originating from sub-Saharan Africa: An investigational study

Emergence and outcomes of the SARS-CoV-2 'Marseille-4' variant

Spreading of new SARS-CoV-2 N501Y spike variant in a new lineage

SARS-CoV-2 variant from India to Marseille: The still active role of ports in the introduction of epidemics

Culture of SARS-CoV-2 in a panel of laboratory cell lines, permissivity, and differences in growth profile

Clinically relevant cell culture models and their significance in isolation, pathogenesis, vaccine development, repurposing and screening of nex drugs for SARS-CoV-2: A systematic review

Rapid viral diagnosis and ambulatory management of suspected COVID-19 cases presenting at the infectious disease referral hospital

The authors declare no conflict of interest. The findings and conclusion of this report are those of the authors and do not represent the views of the Ministère des Armées and Ministère de l'Enseignement Supérieur, de la Recherche et de l'Innovation.