COVID: nasal antiseptic kills virus??

 Dilute solutions of povidone-iodine inactivate SARS-CoV-2 virus and may be usable for nasal antisepsis (see covid nasal antiseptic jamaotol2020 in dropbox, or doi:10.1001/jamaoto.2020.3053)

Details:

--SARS-CoV-2 virus  (strain USA-WAI/2020) viability was tested against aqueous povidone-iodine (PVP-I) solutions diluted to concentrations of 0.5%, 1.25% and 2.5%, and compared to controls (70% ethanol as a positive control and water as a negative one)

--the virus was incubated at room temperature (22 deg C) for 15-30 seconds

--the resulting solutions of virus plus the various dilutions of PVP-1 and controls were then cultured and titers measured

--primary outcome: log reduction after 15 seconds and 30 seconds; surviving virus was quantified and compared with the negative water control

Results:

--at 15 seconds: 

    --all 3 PVP-I concentrations completely inactivated SARS-CoV-2 within 15 seconds:

        --the virus titer for all three concentrations was below the limit of detection

        --there was a log reduction of >3.0 log₁₀ of 50% cell culture infectious dose of virus (CCID₅₀)

    --70% ethanol did NOT completely inactivate the virus after 15 seconds: virus titer 1.5 log₁₀ of CCID₅₀, log reduction of 2.17

    --negative control: no reduction of CCID₅₀; virus titer log₁₀ 3.67 CCID₅₀

--at 30 seconds:

    --all PVP-I dilutions and the ethanol control had no viral detection and log₁₀ reductions of 3.33 of CCID₅₀

--no cytotoxic effects on cells were found after contact with each of the PVP-I concentrations

Commentary:

--the main initial receptor for SARS-CoV-2 are the nasal goblet and ciliated cells, which have the highest concentration of ACE2. it seems that the virus then is aspirated and can infect the lungs after nasal mucociliary clearance. And, a recent trial suggested this same mechanism for influenza A

--PVP-I has proven efficacy for SARS-CoV and MERS infections, in concentrations as low as 0.23%

--PVP-I solutions up to 1.25% did not demonstrate inhibitory effects on the ciliary beat frequency in experimental cell models, suggesting that this concentration would be well-tolerated for short-term applications to nasal epithelium

--clinical studies suggest that PVP-I can be given acutely and over time without adverse effects; one study using a PVP-I dilution of 0.8% every other day in humans for 7 weeks did not find any adverse effects on mucociliary clearance, olfaction or thyroid function

--this study was done by otolaryngologists concerned that their procedures might aerosolize the virus, which can last in the air for up to 3 hours. Hence, the value of quick nasal antisepsis prior to procedures might protect them

--the applied concentrations of the PVP-I solutions will actually be diluted in real life patients: nasal mucous, desquamated cells, other substances in the nose all will dilute the concentration of the PVP-1 and decrease the potential iodine absorption. 

--oral mucosa decontaminated with PVP-1 remains sterilized for up to 4 hours

--if using this PVP-I formulation, it would still make sense to check thyroid function to make sure the iodine load is not adversely affecting this, especially with prolonged use of the PVP-I

Limitations of the study:

--this was a basic science study and not a clinical trial, using solutions of PVP-I of different concentrations with the virus in test-tubes. and using laboratory testing to assess viral loads and cultures to assess viral viability. all of this is reasonable but is different from trials in real people and looking at actual viral transmission

--the safety of the PVP-I solutions has been established only for the 0.08% solutions. further testing would need to be done with the 0.5% solution to assure safety. perhaps the 0.08% solution would be adequate?  should be tested in the lab

--but there should be a trial of the minimum effective PVP-I concentration tested in humans

so, there are some interesting implications of this study:

--it may make sense to decrease SARS-CoV-2 contamination of the nasal turbinates of patients prior to otolaryngeal procedures, which would likely decrease spread of the virus to health care workers (and, this should be tested in a trial)

--it may also benefit other health care workers. perhaps anesthesiologists prior to intubating patients? or those about to give nebulizer treatments?

--perhaps it might be useful for decreasing spread of Covid-infected people to others in the household??

--maybe even useful for decontaminating those with a new potential exposure (eg contacts) to SARS-CoV-2, preventing their developing Covid-19???? and preventing them from spreading the virus to others????

--maybe health care workers themselves should use a solution of PVP-I to decrease potential transmission of the virus when donning/doffing their masks?

geoff

 

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