Thread:
Effect of Chlorhexidine CHX on coronavirus:
CHX concentration tested in various studies till now has been too low.
1st study: CHX 0.02% w/v (1988)
2nd study: 0.01125- 0.015 % w/v (1998)
These conc. are too low & these studies didn't test CHX against coronavirus either
When Hong Kong University researchers increased the Chlorhexidine concentration by just three units i.e. from 0.02% to 0.05% CHX was found to be effective against the coronavirus. CHX was found to be as effective as 7.5% Povidone Iodine or 70% ethyl alcohol.
Hence dental & medical practitioners need not worry about Chlorhexidine gluconate being ineffective against the novel Coronavirus. The concentrations used in the earlier experiments are too low, and worse, they were not even tested against the novel coronavirus.
The CHX conc. tested in early experiments (< 0.02%) was so low that currently no CHX products are available in such low conc.
CHX mouthwashes available in the market (0.12% & 0.2%) now are 2- 4 times more conc. than the CHX conc. that inactivates the novel coronavirus (0.05%).
Chlorhexidine alcohol based hand rubs (0.5% w/v) are TEN times more concentrated than what is needed (0.05%) to inactivate the novel coronavirus.
Chlorhexidine hand scrubs (4% w/v) are EIGHTY times more concentrated than what is needed to inactivate the novel coronavirus.
It means Chlorhexidine is very much effective against novel coronavirus. Hong Kong University study published in The Lancet Microbe says "0.05% CHX works as good as 7.5% Povidone Iodine or 70% Ethyl Alcohol"
So where is the question of CHX being ineffective against coronavirus?
There has been some serious misinterpretation of study results. With the latest study by @hkumed showing that Chlorhexidine is as effective as Povidone Iodine & Ethyl alcohol [even in very low (0.05%) conc.] there is an urgent need to inform dentists & medical practitioners.
To read my analysis of all studies published till now on the topic "Effect of Chlorhexidine on Coronavirus" please download my article from Researchgate. Points to the exact reason why there is a misconception & what should be the correct interpretation researchgate.net/publication/34…
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Neutralizing antibodies are a good indicator of protection,
- not only against severe disease
- but also (if amounts are very high) against viral replication in the mucosa (with or without symptoms), thereby reducing transmission. #COVID19
1/ Omicron's 3 mutations (P681H, H655Y, N679K) in furin cleavage site region were initially predicted to favor its pathogenicity: cell-cell fusion & syncytia formation.
But reality is different.
Omicron's cleavage efficiency is substantially lower than Delta variant. #COVID19
2/ Omicron spike is relatively poorly cleaved.
It shows impaired entry & replication in lung cells that express TMPRSS2, a serine protease enriched in lung alveolar type 1 & 2 cells.
This reduced cleavage is also associated with poorer cell-cell fusion and syncytia formation.
3/ Cell-cell fusion mediated by spike glycoprotein requires S1/S2 cleavage, but is also dependent on TMPRSS2 presence.
Fusogenicity of Omicron spike was severely impaired despite TMPRSS2 expression, leading to marked reduction in syncytium formation compared to Delta spike.