Insight into the role of copper-based materials against the coronaviruses MHV-3, a model for SARS-CoV-2, during the COVID-19 pandemic

Coating high-touch surfaces with inorganic agents, such as metals, appears to be a promising long-term disinfection strategy. However, there is a lack of studies exploring the effectiveness of copper-based products against viruses. In this study, we evaluated the cytotoxicity and virucidal effectiveness of products and materials containing copper against mouse hepatitis virus (MHV-3), a surrogate model for SARS-CoV-2. The results demonstrate that pure CuO and Cu possess activity against the enveloped virus at very low concentrations, ranging from 0.001 to 0.1% (w/v). A greater virucidal efficacy of CuO was found for nanoparticles, which showed activity even against viruses that are more resistant to disinfection such as feline calicivirus (FCV). Most of the evaluated products, with concentrations of Cu or CuO between 0.003 and 15% (w/v), were effective against MHV-3. Cryomicroscopy images of an MHV-3 sample exposed to a CuO-containing surface showed extensive damage to the viral capsid, presumably due to the direct or indirect action of copper ions.

Impact of concentration, temperature and pH on the virucidal activity of alcohols against human adenovirus

BACKGROUND

Adenoviruses belong to the stable nonenveloped viruses playing an important role in healthcare-associated infections mainly causing respiratory infections and epidemic keratoconjunctivitis. Hand disinfection with alcoholic preparations is therefore one of the most important measures to prevent such viral infections in hospitals and other medical settings.

METHODS

The inactivation of adenovirus type 5 by ethanol, 1- and 2-propanol, and 2 commercially available hand disinfectants was examined at different concentrations, temperatures, and pH-values.

RESULTS

For ethanol and 1-propanol the maximum virus-inactivating properties after 30 seconds exposure were found at a concentration of 60%-70% and 50%-60%, respectively, whereas with 2-propanol no activity was observed. The virucidal activity of all alcohols and the 2 hand disinfectants examined was increased when raising the temperature from 20°C to 25°C. By increasing the pH value to 9, a strong improvement of the activity of ethanol, 1-propanol and 1 hand disinfectant was observed, whereas pH lowering resulted in decrease of activity.

CONCLUSIONS

These results demonstrate the importance of physical parameters in the inactivation of adenoviruses by alcohols and will help to improve measures to reduce adenovirus transmission in healthcare settings.

Discovery of novel papain-like protease inhibitors for potential treatment of COVID-19

The recent emergence of different SARS-CoV-2 variants creates an urgent need to develop more effective therapeutic agents to prevent COVID-19 outbreaks. Among SARS-CoV-2 essential proteases is papain-like protease (SARS-CoV-2 PLpro), which plays multiple roles in regulating SARS-CoV-2 viral spread and innate immunity such as deubiquitinating and deISG15ylating (interferon-induced gene 15) activities. Many studies are currently focused on targeting this protease to tackle SARS-CoV-2 infection. In this context, we performed a phenotypic screening using an in-house pilot compounds collection possessing a diverse skeleta against SARS-CoV-2 PLpro. This screen identified SIMR3030 as a potent inhibitor of SARS-CoV-2. SIMR3030 has been shown to exhibit deubiquitinating activity and inhibition of SARS-CoV-2 specific gene expression (ORF1b and Spike) in infected host cells and possessing virucidal activity. Moreover, SIMR3030 was demonstrated to inhibit the expression of inflammatory markers, including IFN-α, IL-6, and OAS1, which are reported to mediate the development of cytokine storms and aggressive immune responses. In vitro absorption, distribution, metabolism, and excretion (ADME) assessment of the drug-likeness properties of SIMR3030 demonstrated good microsomal stability in liver microsomes. Furthermore, SIMR3030 demonstrated very low potency as an inhibitor of CYP450, CYP3A4, CYP2D6 and CYP2C9 which rules out any potential drug-drug interactions. In addition, SIMR3030 showed moderate permeability in Caco2-cells. Critically, SIMR3030 has maintained a high in vivo safety profile at different concentrations. Molecular modeling studies of SIMR3030 in the active sites of SARS-CoV-2 and MERS-CoV PLpro were performed to shed light on the binding modes of this inhibitor. This study demonstrates that SIMR3030 is a potent inhibitor of SARS-CoV-2 PLpro that forms the foundation for developing new drugs to tackle the COVID-19 pandemic and may pave the way for the development of novel therapeutics for a possible future outbreak of new SARS-CoV-2 variants or other Coronavirus species.

Cuprous oxide nanoparticles incorporated into a polymeric matrix embedded in fabrics to prevent spread of SARS-CoV-2

This paper describes the development of a coating for cotton and polypropylene (PP) fabrics based on a polymeric matrix embedded with cuprous oxide nanoparticles (Cu₂O@SDS NPs) in order to inactivate SARS-CoV-2 and manufactured by a simple process using a dip-assisted layer-by-layer technology, at low curing temperature and without the need for expensive equipment, capable of achieving disinfection rates of up to 99%. The polymeric bilayer coating makes the surface of the fabrics hydrophilic, enabling the transportation of the virus-infected droplets to achieve the rapid inactivation of SARS-CoV-2 by contact with the Cu₂O@SDS NPs incorporated in the coated fabrics.

New insights into the antiviral activity of nordihydroguaiaretic acid: Inhibition of dengue virus serotype 1 replication

BACKGROUND

Dengue virus (DENV) is considered one of the most important pathogens in the world causing 390 million infections each year. Currently, the development of vaccines against DENV presents some shortcomings and there is no antiviral therapy available for its infection. An important challenge is that both treatments and vaccines must be effective against all four DENV serotypes. Nordihydroguaiaretic acid (NDGA), isolated from Larrea divaricata Cav. (Zygophyllaceae) has shown a significant inhibitory effect on a broad spectrum of viruses, including DENV serotypes 2 and 4.

PURPOSE

We evaluated the in vitro virucidal and antiviral activity of NDGA on DENV serotype 1 (DENV1), including the study of its mechanism of action, to provide more evidence on its antiviral activity.

METHODS

The viability of viral particles was quantified by the plaque-forming unit reduction method. NDGA effects on DENV1 genome and viral proteins were evaluated by qPCR and immunofluorescence, respectively. Lysosomotropic activity was assayed using acridine orange and neutral red dyes.

RESULTS

NDGA showed in vitro virucidal and antiviral activity against DENV1. The antiviral effect would be effective within the first 2 h after viral internalization, when the uncoating process takes place. In addition, we determined by qPCR that NDGA decreases the amount of intracellular RNA of DENV1 and, by immunofluorescence, the number of cells infected. These results indicate that the antiviral effect of NDGA would have an intracellular mechanism of action, which is consistent with its ability to be incorporated into host cells. Considering the inhibitory activity of NDGA on the cellular lipid metabolism, we compared the antiviral effect of two inhibitors acting on two different pathways of this type of metabolism: 1) resveratrol that inhibits the sterol regulatory element of binding proteins, and 2) caffeic acid that inhibits the 5-lipoxygenase (5-LOX) enzyme. Only caffeic acid produced an inhibitory effect on DENV1 infection. We studied the lysosomotropic activity of NDGA on host cells and found, for the first time, that this compound inhibited the acidification of cell vesicles which would prevent DENV1 uncoating process.

CONCLUSION

The present work contributes to the knowledge of NDGA activity on DENV. We describe its activity on DENV1, a serotype different to those that have been already reported. Moreover, we provide evidence on which stage/s of the viral replication cycle NDGA exerts its effects. We suggest that the mechanism of action of NDGA on DENV1 is related to its lysosomotropic effect, which inhibits the viral uncoating process.

Potential of graphene based photocatalyst for antiviral activity with emphasis on COVID-19: A review

Coronavirus disease-2019 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been one of the most challenging worldwide epidemics of recent times. Semiconducting materials (photocatalysts) could prove effectual solar-light-driven technology on account of variant reactive oxidative species (ROS), including superoxide (^•O₂ ^- ) and hydroxyl (^•OH) radicals either by degradation of proteins, DNA, RNA, or preventing cell development by terminating cellular membrane. Graphene-based materials have been exquisitely explored for antiviral applications due to their extraordinary physicochemical features including large specific surface area, robust mechanical strength, tunable structural features, and high electrical conductivity. Considering that, the present study highlights a perspective on the potentials of graphene based materials for photocatalytic antiviral activity. The interaction of virus with the surface of graphene based nanomaterials and the consequent physical, as well as ROS induced inactivation process, has been highlighted and discussed. It is highly anticipated that the present review article emphasizing mechanistic antiviral insights could accelerate further research in this field.

Efficacy of disinfectants for inactivation of Ebola virus in suspension by integrated cell culture coupled with real-time RT-PCR

BACKGROUND

Ebola virus can be transmitted by contact with environmental surfaces (fomites) contaminated with secretions and excretions from infected individuals. Due to their potential to cause a public health emergency and the absence of efficacious drugs and vaccines, a crucial intervention may involve the use of an effective virucidal agent for disinfecting contaminated surfaces.

METHODS

In this study, the virucidal efficacy of three disinfectants against Ebola virus, Micro-Chem Plus detergent disinfectant cleaner (MCP), FWD and ethanol, was evaluated in suspension tests according to the Technical Standard for Disinfection of China. All products at different concentrations were tested with application times ranging from 15 s to 8 min by using a quantitative suspension test, and a comparative inactivation analysis was performed. A reduction in the virus titre of ≥4 log10 was regarded as evidence of virucidal activity.

RESULTS

MCP and FWD, which contain dual quaternary ammonium compounds, are highly effective at inactivating the Ebola virus within 15 s of contact time, despite a slight difference between them at lower concentrations. Similar to the results in the literature, our results confirmed the excellent virucidal activity of medical ethanol for Ebola virus, which can reduce viral titres to background levels within 15 s at a concentration of 38% (v/v).

CONCLUSION

These three disinfectants display sufficient inactivation efficacy for the Ebola virus at reasonably short contact times, which may be practically achieved in the field. The use of these disinfectants for decontamination in health care settings and laboratories could mitigate the risk of Ebola virus transmission.

Evaluating the virucidal activity of four disinfectants against SARS-CoV-2

BACKGROUND

The recent COVID-19 pandemic highlights the need for efficacious virucidal products to limit the spread of SARS-CoV-2. Several studies have suggested that alcohol-based sanitizers and some disinfectants are effective. While virucidal activity data of low-level disinfectants are lacking and some conclusions are not clear yet.

METHODS

We evaluated the virucidal activity of 2 quaternary ammonium compounds (QAC) disinfectants (MICRO-CHEM PLUS and FWD), W30 (an amphoteric surfactant), and Medical EtOH against SARS-CoV-2. Suspension tests covering different concentration and contact time were performed using the integrated cell culture-qPCR method.

RESULTS

Each of disinfectants was effective at inactivating SARS-CoV-2. MCP and FWD are highly effective within 15 seconds. W30 is also efficient within 2 minutes at concentration of 1%. Consistent with previous report, our results also demonstrated that 38% ethanol was sufficient to completely inactivate virus, which proved the method used in this study is feasible.

CONCLUSIONS AND DISCUSSION

QAC disinfectants, MCP and FWD, are highly effective for the inactivation of SARS-CoV-2, which making them practical for use in health care setting and laboratories where prompt disinfection is important. The low-level disinfectant based on amphoteric surfactant, W30, which may present in commonly available household hygiene agents is also able to inactivate SARS-CoV-2.

Evaluation of the substitution of poliomyelitis virus for testing virucidal activities of instrument and surface disinfection

The Global Polio Eradication initiative has the goal to eradicate poliomyelitis worldwide. This means that poliomyelitisvirus type 1 strain LSc 2ab (PV-1) can no longer be used for the evaluation of virucidal activity of chemical disinfectants. In this study, we evaluated murine parvovirus ATCC VR 1346 (minute virus of mice, MVM) as suitable surrogate for PV-1 when testing virucidal activity of biocides in instrument and surface disinfectants. Suspension testing in different laboratories with two commercially available active biocidal substances based on glutaraldehyde (GDA 0.01 % to 0.25 %) and peracetic acid (PAA 0.005 % to 0.1%) with an exposure time of 30 minutes was performed. Both pathogens showed comparable susceptibility and dose-dependent reduction of virus titers following German and European Guidelines.

Isolation and evaluation of virucidal activities of flavanone glycosides and rosmarinic acid derivatives from Dracocephalum spp. against feline calicivirus

Feline calicivirus is one of the surrogate viruses of human norovirus. This study aimed to identify virucidal compounds, chemical constituents of plants from the genus Dracocephalum, which are rich in flavonoids and phenylpropanoid oligomers. Four undescribed compounds, including a flavanone glucoside, two stilbenoid glycosides, and a phenylpropanoid amide glycoside, as well as 17 known compounds, were isolated from the Mongolian plants Dracocephalum fruticulosum Stephan ex Willd., and D. nutans L. belonging to the family Lamiaceae. The structures of the compounds were determined based on NMR, MS, and electronic CD spectroscopic data. In addition to these 21 compounds, 15 previously reported compounds from D. foetidum Bunge in C.F. von Ledebour were included, and a total of 36 compounds were evaluated for their virucidal activities against feline calicivirus. Some of the flavanone glycosides and phenylpropanoid oligomers showed virucidal activities, and their structural features are discussed. The findings suggest that isosakuranetin glycosides and phenylpropanoid oligomers may have the potential for norovirus inactivation.

Virucidal activity of oral care products against SARS-CoV-2 in vitro

OBJECTIVE

Coronavirus disease 2019 (COVID-19) caused by infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide. Since reducing the amount of virus in saliva is considered to prevent broader infection, the Center for Disease Control (CDC) and American Dental Hygienists' Association (ADHA) have recommended use of CPC- or CHX-containing oral care products before the dental procedure. However, there is no certified evidence. So, we examined inactivation of SARS-CoV-2 by oral care products in several countries in vitro.

METHODS

0.05 % Cetylpyridinium chloride (CPC) mouthwash, 0.05 % CPC toothpaste and 0.30 % CPC spray in Japan; 0.06 % chlorhexidine gluconate (CHX) + 0.05 % CPC mouthwash and 0.12 % CHX + 0.05 % CPC mouthwash in Europe; 0.075 % CPC mouthwash, 0.12 % CHX mouthwash, and 0.20 % delmopinol hydrochloride mouthwash in the USA; and 0.04 % CPC mouthwash in China were assessed for their virucidal activity with ASTM E1052.

RESULTS

The virus was inactivated in vitro by the contact time in directions for use of all oral care products containing CPC or delmopinol hydrochloride as anticeptics.

CONCLUSIONS

These results suggest that these oral care products in each country may reduce the viral load in the mouth.

Evaluation of virucidal activity of fabrics using feline coronavirus

Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2) is an enveloped RNA virus responsible for the 2019 coronavirus disease (COVID-19) that represents a global health threat, causing an ongoing pandemic in many countries and territories. WHO recommendations emphasize the importance of all personal protective equipment (PPE) that can interrupt COVID-19 transmission. The textile industry and scientists are developing hygienic fabrics by the addition of or treatment with various antimicrobial and antiviral compounds. Methods for determining the antiviral activity of fabrics are reported in the International Standards Organization (ISO) 18184 (2019) guidelines.

Three different fabric samples treated with silver derivate, copper derivative and a not treated cotton fabric used as control were examined and put in contact with a suspension of feline coronavirus (FCoV). After 2 h of incubation a significant decrease of viral titer, as high as 3.25 log10 Tissue Culture Infectious Dose (TCID)₅₀/50 μl, in feline cells was observed in treated fabrics, with respect to not treated fabrics.

In this study, we optimized laboratory methods to evaluate the virucidal activity of silver- and copper treated cotton- based fabrics against coronavirus, using FCoV suitable as a surrogate of SARS-CoV-2 but safe for laboratory technicians.

Effect of the Photocatalyst under Visible Light Irradiation in SARS-CoV-2 Stability on an Abiotic Surface

There is a worldwide attempt to develop prevention strategies against SARS-CoV-2 transmission. Here we examined the effectiveness of tungsten trioxide (WO₃)-based visible light-responsive photocatalyst on the inactivation of SARS-CoV-2 under different temperatures and exposure durations. The viral titer on the photocatalyst-coated glass slides decreased from 5.93 ± 0.38 logTCID₅₀ /mL to 3.05 ±. 25 logTCID₅₀/mL after exposure to 3,000 lux of the visible light irradiation for 6h at 20℃. On the other hand, lighting without the photocatalyst, or the photocatalyst-coat without lighting retained viral stability. Immunoblotting and electron microscopic analyses showed the reduced amounts of spike protein on the viral surface after the photocatalyst treatment. Our data suggest a possible implication of the photocatalyst on the decontamination of SARS-CoV-2 in indoor environments, thereby preventing indirect viral spread.

Virucidal efficacy of different formulations for hand and surface disinfection targeting SARS CoV-2

In the ongoing SARS CoV-2 pandemic, effective disinfection measures are needed, and guidance based on the methodological framework of the European Committee for Standardization (CEN) may enable the choice of effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming ‘virucidal activity against enveloped viruses’ as specified in the European Standard EN 14476 as well as in the German Association for the Control of Viral Diseases/Robert Koch Institute (DVV/RKI) guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in the EN 14476 and DVV/RKI guidelines. Thus, chemical disinfectants claiming ‘virucidal activity against enveloped viruses’ based on the EN 14476 and DVV/RKI guidelines will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

Antiviral activity of sulfated polysaccharides from marine algae and its application in combating COVID-19: Mini review

Marine-derived sulfated polysaccharides possess various antiviral activities against a broad range of enveloped and non-enveloped viruses. It has become the potential source of antiviral drugs for pharmaceutical development. In this review, we will discuss the different types of sulfated polysaccharides and their structural classification. Some of the major sulfated polysaccharides with potent antiviral activity, including carrageenan, agar, ulvan, fucoidan, and alginates, are considered in this review. The mechanism of these sulfated polysaccharides in inhibiting the different stages of the viral infection process inside the host cell is also demonstrated. It involves blocking the initial entry of the virus or inhibiting its transcription and translation by modulating the immune response of the host cell. In addition, we explore the potential of sulfated polysaccharides as antiviral agents in preventing recent Corona Virus Disease-2019 (COVID-19).

Decontamination efficacy of sodium hypochlorite solutions for poliovirus

Effective decontamination procedures are critical to the successful manufacture and control of poliovirus vaccines to minimize the risk to personnel and the environment. Polio viruses have been reported to be more resistant to disinfectants than many other viruses. We assessed the efficacy of sodium hypochlorite-containing disinfectants for decontamination for three poliovirus serotypes to implement decontamination procedures that are fully compliant with the WHO GAP III and Health authorities' requirements. A 10.4 log reduction was observed with a 0.63% sodium hypochlorite solution in a suspension with high protein and high poliovirus concentrations diluted 10-fold compared with a 6 log reduction in an undiluted sample. Treatment efficacy increased with sodium hypochlorite content and decreased with sample protein content. The surface tests showed that two 1-min treatments, 5-min apart, with a 0.63% Chl sodium hypochlorite solution effectively reduced the concentration of all poliovirus serotypes by 10 log₁₀, irrespective of the protein and virus concentration in the sample. Sodium hypochlorite solutions lower than 0.52% were less effective for complete inactivation of poliovirus. In conclusion, we demonstrated that a high level of virus reduction (>10 log₁₀) can be achieved with sodium hypochlorite solutions with poliovirus in suspension and dried on surfaces.

Antiviral activity of native banana lectin against bovine viral diarrhea virus and bovine alphaherpesvirus type 1

Bovine viral diarrhea virus (BVDV) and bovine alphaherpesvirus type 1 (BoHV-1) are responsible for major economic losses of livestock worldwide, making their eradication an important objective of veterinary research. Vaccines against these infectious agents are commercially available but have some limitations due to the specific features of these viral agents. The development of new antiviral drugs is therefore essential. Native banana lectin (BanLec) is a lectin isolated from banana fruit (Musa acuminata) and has a high affinity for mannose glycans found in several viral envelopes. The inhibitory properties of this lectin against several viruses has already been demonstrated. The aim of this work was therefore to test the antiviral and virucidal activities of BanLec against BVDV-1 and BoHV-1. Its antiviral activity was assessed by measuring the viral titer and viability of susceptible Madin-Darby Bovine Kidney cells (MDBK) treated with BanLec before and after viral infection. The virucidal properties of BanLec were determined by preincubation of the lectin with the viruses, followed by measurement of the viral load in exposed cells. Treatment with 25 μg/mL BanLec resulted in high levels of inhibition against BVDV-1 (99.98%) and BoHV-1 (99.68%) without affecting cell viability, demonstrating promising potential as an antiviral agent.

Virucidal activity of ginger essential oil against caprine alphaherpesvirus-1

The emergence of alphaherpesvirus strains resistant to commonly used antiviral drugs has prompted the research for alternative, biologically active anti-herpetic agents. Essential oils (EOs) have shown anti-infective properties against human herpes simplex viruses (HSV-1 and -2). Caprine alphaherpesvirus 1 (CpHV-1) induces genital lesions in its natural host and it is regarded as a useful homologous animal model for the study of HSV-2 infection, chiefly for the assessment of antiviral drugs in in vivo studies. In the present study we evaluated the activity in vitro of ginger EO (GEO) against CpHV-1. GEO was found to be effective as virucide on cell-free virus, inactivating CpHV-1 up to 100%. The virucidal activity of GEO is likely accounted for by disruption of herpesvirus envelope and its associated structures which are necessary for virus adsorption and entry into host cells. On the opposite, GEO was not able to inhibit virus adsorption and/or replication, as treatment of cells before and after infection did not abolish virus infectivity. GEO could be suggested for topical applications in in vivo experiments using CpHV-1/goat model, since the lipophilic nature of EOs favours their adsorption through the cutaneous/mucosal barrier, either alone or in conjunction with other molecules. These findings open several perspectives in terms of therapeutic possibilities for a number of human and animal alphaherpesviruses.

Virucidal and Neutralizing Activity Tests for Antiviral Substances and Antibodies

In a narrow definition, virucidal activity represents the activity by which to interact with and physically disrupt viral particles. In a broad definition, it includes the activity by which to functionally inhibit (neutralize) viral infectivity without apparent morphological alterations of the viral particles. The viral infectivity can be measured in cell culture system by means of plaque assay, infectious focus assay, 50% tissue culture infectious dose (TCID₅₀) assay, etc. Morphologically, disruption of viral particles can be demonstrated by negative staining electron microscopic analysis of viral particles. In this article, we describe methods to assess virucidal activity in a broad definition.

Bactericidal and Virucidal Activity of Povidone-Iodine and Chlorhexidine Gluconate Cleansers in an In Vivo Hand Hygiene Clinical Simulation Study

Introduction

Standard in vitro and in vivo tests help demonstrate efficacy of hand hygiene products; however, there is no standard in vivo test method for viruses. We investigated the bactericidal and virucidal efficacy of povidone-iodine (PVP-I) 7.5% scalp and skin cleanser, chlorhexidine gluconate (CHG) 4% hand cleanser and the reference hand wash (soft soap) in 15 healthy volunteers following European Standard EN1499 (hygienic hand wash test method for bacteria), which was adapted for virucidal testing.

Methods

Separate test series were performed for bactericidal (Escherichia coli) and virucidal [murine norovirus (MNV)] testing. After pre-washing and artificial contamination of hands with test organisms, volunteers underwent testing with 3 and 5 mL of each product for contact times of 15, 30 and 60 s according to a Latin-square randomization. The number of test organisms released from fingertips into sampling fluids was assessed before and after hand washing and mean log₁₀ reduction factor (RF) was calculated. RFs (test-reference) were compared using a Wilcoxon–Wilcox multiple comparisons test per EN1499; efficacy was concluded if p ≤ 0.01.

Results

PVP-I 7.5% and CHG 4% cleansers both passed EN1499 requirements against E. coli, with statistically significantly greater (p ≤ 0.01) mean log₁₀ RFs compared with reference soft soap across all tests (PVP-I: 4.09–5.27; CHG: 4.12–5.22; soap: 2.75–3.11). The experimental design using EN1499 was applicable to testing with MNV as discriminatory and reproducible results were generated. Mean log₁₀ RFs of MNV were statistically significantly greater for PVP-I (1.57–2.57) compared with soft soap (1.24–1.62), while mean log₁₀ RFs with CHG (0.90–1.34) were lower than for soft soap across all tests.

Conclusion

PVP-I 7.5% cleanser showed superior efficacy against MNV compared to soft soap and CHG 4% cleanser, while both PVP-I and CHG were superior to soft soap against E. coli. The experimental set-up may be applicable to future testing for antiviral hand washes.

Funding

Mundipharma Manufacturing Pte Ltd.

Plain Language Summary

Plain language summary available for this article.

Anti-influenza viral effects of honey in vitro: potent high activity of manuka honey

BACKGROUND AND AIMS

Influenza viruses are a serious threat to human health and cause thousands of deaths annually. Thus, there is an urgent requirement for the development of novel anti-influenza virus drugs. Therefore, the aim of this study was to evaluate the anti-influenza viral activity of honey from various sources.

METHODS

Antiviral activities of honey samples were evaluated using MDCK cells. To elucidate the possible mechanism of action of honey, plaque inhibition assays were used. Synergistic effects of honey with known anti-influenza virus drugs such as zanamivir or oseltamivir were tested.

RESULTS

Manuka honey efficiently inhibited influenza virus replication (IC50 = 3.6 ± 1.2 mg/mL; CC50 = 82.3 ± 2.2 mg/mL; selective index = 22.9), which is related to its virucidal effects. In the presence of 3.13 mg/mL manuka honey, the IC50 of zanamivir or oseltamivir was reduced to nearly 1/1000th of their single use.

CONCLUSIONS

Our results showed that honey, in general, and particularly manuka honey, has potent inhibitory activity against the influenza virus, demonstrating a potential medicinal value.

Efficacy of hand rubs with a low alcohol concentration listed as effective by a national hospital hygiene society in Europe

Background

Some national hospital hygiene societies in Europe such as the French society for hospital hygiene (SFHH) have positive lists of disinfectants. Few hand disinfectants with a rather low concentration of ethanol are listed by one society as effective for hygienic hand disinfection with 3 mL in 30 s including a virucidal activity in 30 s or 60 s, but published data allow having doubts. We have therefore evaluated the efficacy of three commonly used hand disinfectants according to EN 1500 and EN 14476.

Methods

Products 1 (Aniosgel 85 NPC) and 2 (Aniosrub 85 NPC) were based on 70% ethanol, product 3 (ClinoGel derma+) on 60% ethanol and 15% isopropanol (all w/w). They were tested in 3 laboratories according to EN 1500. Three mL were applied for 30 s and compared to the reference treatment of 2 × 3 mL applications of isopropanol 60% (v/v), on hands artificially contaminated with Escherichia coli. Each laboratory used a cross-over design against the reference alcohol with 15 or 20 volunteers. The virucidal activity of the products was evaluated (EN 14476) in one laboratory against adenovirus and poliovirus in different concentrations (80%, 90%, 97%), with different organic loads (none; clean conditions; phosphate-buffered saline) for up to 3 min.

Results

Product 1 revealed a mean log₁₀-reduction of 3.87 ± 0.79 (laboratory 1) and 4.38 ± 0.87 (laboratory 2) which was significantly lower compared to the reference procedure (4.62 ± 0.89 and 5.00 ± 0.87). In laboratory 3 product 1 was inferior to the reference disinfection (4.06 ± 0.86 versus 4.99 ± 0.90). Product 2 revealed similar results. Product 3 fulfilled the requirements in one laboratory but failed in the two other. None of the three products was able to reduce viral infectivity of both adenovirus and poliovirus by 4 log₁₀ steps in 3 min according to EN 14476.

Conclusions

Efficacy data mentioned in a positive list published by a society for hospital hygiene should still be regarded with caution if they quite obviously contradict published data on the same or similar products.