Thread by @OttoKolbl

Throat spray Povidone-Iodine or hydroxychloroquine are efficient as prevention against COVID-19: A peer-reviewed randomized study with >3000 participants in a migrant home in Singapore with high incidence: Control group incidence 70.0% after 42 days. 1/
sciencedirect.com/science/articl…

After compensating for var. factors, throat spray povidone-iodine decreases risk of infection by 60-64%, i.e. by more than half; hydroxychloroquine by 61-66%; both signif. p<0.0125. Vit. C + zinc by 55-58% (compared to only vit. C), according to study not signif. (see below). 2/

Question 1: All data and samples were ready on July 13 2020. This study can save hundreds of thousands of lives, but the results were published online only on April 20 2021. No preprint. Why? Because the team got funding for one year and must justify it? 3/

Quest. 2: This is a prospective randomized open-label study (n>3000), i.e. the highest standard possible for a treatment where participants and staff will know what they get (throat spray is not the same as pill once, once daily, etc.). 4/

Quest. 2b: After the results were held back for more than half a year, will somebody realize that throat sprays with povidone-iodine (e.g. Betadine) have got a potential, issue official recommendations and fund further research? 5/

Quest. 2c: Research results indicate that gargling is more efficient than sprays because of the flushing out effect. We also know that active ingredients can be combined, i.e. hypertonic saline with povidone-iodine. Additional nasal rinse is even better.6/
researchgate.net/publication/35…

Quest. 2d: How many years will our researchers need before they can tell us whether and in which form gargling and nasal rinse are efficient against COVID-19, now that we have got so many research results which indicate considerable potential?

Q3: Does the efficiency of the throat spray come from self-protection or from protecting others? On average, roughly half of the residents of the home took part, always with the same treatment for each floor. Decreasing viral load protecting others might have played a role. 8/

Quest. 3b: How do you measure protection of others? You don't need thousands of participants, a few tens are enough, but viral load must be measured with cell cultures, not with PCR-Tests, as is done nowadays. Methodology exists since 2005: 9/
doi.org/10.1111/j.1600…

Quest. 4: Why did no Western media (except weather(dot)com) report about the study, only media from Southeast Asia, India and China? Academic nationalism? Too embarrassing that low-tech medication rejected by our experts turns out to be efficient? 10/

Details: Throat spray povidone-iodine concentration 0.45% 3x daily decreases incidence from 70.0% (control group) to 46.0% (absolute -24%, relative -34%), adjusted odds ratio (compensating for var. factors) , 6 models) aOR 36-40%, decrease by 60-64%, significant p<0.0125. 11/

Hydroxychloroquine group (1x 400mg, then 200mg daily): decreases incidence from 70.0% (control) to 49.1% (absolute -20.9%, relative -30%), adjusted odds ratio (compensating for var. factors, 6 models) aOR 34-39%, decrease by 61-66%, significant p<0.0125. 12/

Group vit. C (2x daily 250mg) + zinc (2x daily 40mg) versus control group vit. C 500mg 1x daily: Risk minus 55-58%, not significant p<0.0125 (according to Bonferroni correction), but significant p<0.05. 13/

Since the study contains four comparisons, the authors adapted the p value, therefore 0.0125 instead of 0.05. All other studies (from memory) use 0.05 in this case; this can be justified by the fact that the purpose is not to exclude a combined null hypothesis. 14/

If we measure with the same yardstick as other studies (each treatment in comparison to control group is a separate research question), we can consider vit. C + zinc (compared to only vit. C) as significant, since p<0.05. 15/

Ivermectine was also evaluated, but with one single 12mg dose for the whole study over 42 days; it was found to have little impact. The authors write that with a regular dose, impact could have been greater. Probably regular dose is not authorized in Singapore. 16/16