September 11, 2020
A preprint* released two days ago reports a small randomized controlled trial suggesting that gargling with povidone-iodine clears the virus from the nose and throat within four days.
20 asymptomatic or pre-symptomatic COVID-19 patients from a Malaysian university hospital were randomly allocated into four groups:
Group A gargled with 10 milliliters of 1% povidone-iodine for 30 seconds, three times per day.
Group B did the same with 20 milliliters of Listerine.
Group C did the same thing with 100 milliliters of tap water.
Group D acted as untreated controls.
The patients ranged in age from 22 to 56, had positive PCR tests for COVID-19 but hadn't developed any symptoms yet, were enrolled within 5 days of being tested, and did not receive any other treatments.
Two patients had co-morbidities: one had asthma and one had obesity. Unfortunately, they didn't report which groups these two patients were in.
On day 4, 100% of those in the povidone-iodine group had cleared the virus. By contrast, 80% of those in the Listerine group, 40% of those in the tap water group, and 20% of those in the control group had cleared the virus.
The one patient in the Listerine group who had not cleared the virus on day 4 was still positive on day 6 and was indeterminate on day 12.
Of the three patients who remained positive on day 4 in the tap water group, two became indeterminate on day 6, but one of them slipped back into positive by day 12. No one who wasn't negative on day 4 cleared the virus by day 12.
In the control group, one person tested negative on day 4, but slipped into the positive or indeterminate territory by day 6. On day 12, still only one person tested negative.
Due to its small size, the study did not have the statistical power to compare every group. However, the difference between the povidone-iodine group and the control group was statistically significant at every day.
This study is small and was not blinded. Further studies will be needed to test this in larger samples, different populations, and to see if this treatment is effective in more serious cases where symptoms or complications have developed. Nevertheless, it provides preliminary results suggesting that gargling with povidone-iodine and Listerine can both help clear the virus, and that povidone-iodine is most effective.
I covered how to use povidone-iodine in the nose, mouth, and throat on May 28 in this newsletter, and followed that post with important safety information on May 31. In my August 30 update of “What I'm Doing for the Coronavirus,” I covered how I use nasal irrigation with povidone-iodine myself.
The Food and Supplement Guide for the Coronavirus has included a protocol for the use of povidone-iodine since version 4.0, released on May 28, and is now in version 6.0, released on September 3. These new results validate the inclusion povidone-iodine in the protocol. Purchases of the guide help support this free newsletter, and I am grateful for any support you can offer.
Stay safe and healthy,
Chris
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*Footnotes
* The term “preprint” is often used in these updates. Preprints are studies destined for peer-reviewed journals that have yet to be peer-reviewed. Because COVID-19 is such a rapidly evolving disease and peer-review takes so long, most of the information circulating about the disease comes from preprints.