Summary of COVID-19 chlorhexidine studies
1. Jing et al., Effective early strategy to prevent olfactory and gustatory dysfunction in COVID-19: a randomized controlled trial
260 patient chlorhexidine early treatment RCT: 79% lower progression (p<0.0001) and 97% lower severe cases (p<0.0001).RCT 379 mild COVID-19 cases showing significantly lower prevalence and severity of olfactory and gustatory dysfunction with budesonide nasal spray, chlorhexidine mouthwash, and saline nasal irrigation. The control group received no intervention, the saline group received saline nasal irrigation plus saline nasal spray and mouthwash, and the drug group received saline nasal irrigation plus budesonide nasal spray and chlorhexidine mouthwash. Saline nasal irrigation plus nasal spray and mouthwash were administered once and four times daily, respectively. Both treatment groups had significantly lower prevalence and severity olfactory and gustatory dysfunction. Prevalence was lower for the drug vs. saline group, without statistical significance.
Nov 2023, QJM: An Int. J. Medicine, https://academic.oup.com/qjmed/advance-article/doi/10.1093/qjmed/hcad262/7439598, https://c19p.org/jing
294 patient chlorhexidine late treatment RCT: 75% improved viral clearance (p<0.0001).
RCT 294 hospitalized patients in the USA, showing faster oropharyngeal viral clearance with chlorhexidine. Results were better with a combination of oropharyngeal rinse and posterior oropharyngeal spray compared with the rinse alone.
Apr 2021, J. Medical Virology, https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jmv.26954, https://c19p.org/huang8
3. Karami et al., A Comparison of the Effects of Chlorhexidine and Sodium Bicarbonate Mouthwashes on COVID-19–Related Symptoms
76 patient chlorhexidine prophylaxis RCT: 61% lower progression (p=0.04) and 57% fewer cases (p=0.03).RCT 116 healthcare workers comparing 0.2% chlorhexidine mouthwash (n=36), 7.5% sodium bicarbonate mouthwash (n=40), and placebo (n=40) twice daily for 2 weeks, with symptoms followed for 4 weeks. There were lower symtoms and cases in both treatment groups, with statistical significance for chlorhexidine only. The treatments were stopped after two weeks, results may be better with continued use, more frequent use, and with the addition of nasal use.
Jan 2024, Iranian J. Nursing and Midwifery Research, https://journals.lww.com/jnmr/fulltext/2024/29010/a_comparison_of_the_effects_of_chlorhexidine_and.8.aspx, https://c19p.org/karami
4. Sulistyani et al., Effects of chlorhexidine gluconate and povidone-iodine mouthwash on cycle threshold values in patients infected with SARS-CoV-2
30 patient chlorhexidine early treatment study: 54% improved viral clearance (p=0.001).Prospective study of 45 COVID-19 patients showing improved viral clearance with chlorhexidine gluconate and povidone-iodine mouthwash use.
Apr 2025, Dental and Medical Problems, https://dmp.umw.edu.pl/en/article/2025/62/2/217/, https://c19p.org/sulistyani2
5. Bonn et al., Efficacy of a Mouthwash Containing CHX and CPC in SARS-CoV-2–Positive Patients: A Randomized Controlled Clinical Trial
61 patient chlorhexidine early treatment RCT: 85% improved viral clearance (p=0.2).RCT 61 COVID+ patients showing improved reduction in viral infectivity with a mouthwash containing 0.05% cetylpyridinium chloride (CPC) and 0.05% chlorhexidine digluconate (CHX), compared to 0.9% NaCl. The study only analyzes short-term changes in viral load 30 minutes after treatment.
Mar 2023, J. Dental Research, https://journals.sagepub.com/doi/10.1177/00220345231156415, https://c19p.org/bonn