March 19, 2020

COVID-19 Precautions to Reduce Risk of Transmission and Illness

There are well-known basic protective measures to prevent spread of viral illnesses like COVID-19 including washing hands frequently, stay home, avoid touching your face, maintain social distancing, cleaning surfaces routinely, wear a mask, etc. However, there are also some interesting reports of other interventions that may provide further protection that one may not know about.

1) Published back in 2004, researchers noted that daily saline nasal spray (plain old saltwater) use appears to significantly prevent symptoms of the common cold (which includes coronaviruses) in a population of otherwise healthy adults [link]. Needless to say, one should avoid sharing the same saline nasal spray bottle.

There is also this research that determined 0.23% betadine (aka, providone iodine prep solution) rapidly kills both bacteria and viruses within 15 seconds (in vitro).

Finally, a small study in 2021 suggests that betadine gargles and nasal flushes eradicate COVID in patients who are actively infected within 3 days.

Based on all this data, some ENTs advocate that saline rinses twice a day would probably work better than saline nasal spray. Additionally, adding betadine into the saline mixture might confer additional benefit due to their virucidal effects. A meta-analysis also supported use of betadine in this fashion.

To make your own 1% betadine saline solution to use in the nose whether by spray or rinse, just add 2.4 ml of 10% betadine to 8 ounces (240ml) of saline. Just be aware of a mild temporary nasty aftertaste after using.

There is a stain-free and "better" tasting betadine-like solution called ioRinse. Make sure to get the ENT-specific concentrate formulation. If Amazon not carrying, you can purchase directly from the manufacturer.

2) More recently in 2020, researchers have reported that high temperatures and high humidity appear to decrease transmission of COVID-19. This was based on transmission rates documented in different Chinese cities under different weather conditions during the COVID-19 pandemic [link]. This would also make sense from observational data that viral illnesses are worse during the dry winter months compared to the humid summer months in the United States and elsewhere. It may behoove to raise home/office temperatures and use active humidification based on this data.

3) Also, always park your car under the sun. Research suggests that rapid inactivation of COVID-19 occurs at heated temperatures; surfaces "were converted to be non-infectious after 90-, 60- and 30-min exposure at 56 degrees Celsius, at 67 degrees Celsius, and at 75 degrees Celsius, respectively." 75 degrees Celsius is 167 degrees F, a temperature which certainly occurs if not even higher when a car is parked under the sun for a prolonged period of time [link]. Furthermore, UV rays from sunlight also is known to eradicate COVID-19 on surfaces. You can purchase UV-C containers or wands to sterilize small items at home.

With respect to heat inactivation, one can use a slow cooker that can even fit a turkey to sterilize many more items quickly. More info on this here.

4) Given there is increasing concern that COVID-19 may be able to spread via airborne aerosol droplets though definitive "proof" still lacking [link], obtaining a high quality HEPA room filter can minimize airborne spread if true. COVID-19 is 0.125 microns in size but is suspected to spread thru the air on aerosol droplets 0.5 microns and higher. HEPA filters can definitely capture any particles larger than 0.3 microns in size, but according to this NASA study, it should also be able to effectively clear particles down to 0.01 microns in size and as such should effectively clear any COVID-19 from the air. Interestingly, HEPA filters work better at low fan speeds as it allows the air to have longer contact time with the filter. Our office typically recommends HEPA filters made by Alen and Dyson. Obviously, this intervention can also help minimize allergies as it would also remove pollen and other allergens from the air.

5) Take Vit D3 supplementation (5000 IU per day). Recent studies suggest that low vitamin D levels increase risk of illness and mortality with COVID-19. All studies are observational which limits the strength of this association, but given vitamin D3 supplementation has no significant downsides, it certainly can not hurt to take and certainly can only help.

As more research appears describing "simple" things anyone can do at home to help prevent viral diseases spread... I will add to this blog post over time.

A daily nasal spray with saline prevents symptoms of rhinitis. Acta Otolaryngol. 2004 Nov;124(9):1059-62.

In Vitro Bactericidal and Virucidal Efficacy of Povidone-Iodine Gargle/Mouthwash Against Respiratory and Oral Tract Pathogens. Infect Dis Ther. 2018 Jun; 7(2): 249–259.

Consideration of povidone-iodine as a public health intervention for COVID-19: Utilization as “Personal Protective Equipment” for frontline providers exposed in high-risk head and neck and skull base oncology care. Oral Oncol. 2020 Apr 16 : 104724. 

Topical preparations to reduce SARS‐CoV‐2 aerosolization in head and neck mucosal surgery. Head & Neck. First published: 25 April 2020. 

Povidone Iodine Mouthwash, Gargle, and Nasal Spray to Reduce Nasopharyngeal Viral Load in Patients With COVID-19. JAMA Otolaryngol Head Neck Surg. Published online February 4, 2021. doi:10.1001/jamaoto.2020.5490 

High Temperature and High Humidity Reduce the Transmission of COVID-19 (March 9, 2020). Available at SSRN: or

Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. New England Journal of Medicine. March 17, 2020.

Role of vitamin D in preventing of COVID-19 infection, progression and severity. J Infect Public Health. 2020;S1876-0341(20)30531-1. doi:10.1016/j.jiph.2020.06.021

Effects of Vitamin D on COVID-19 Infection and Prognosis: A Systematic Review. Risk Manag Healthc Policy. 2021 Jan 7;14:31-38. doi: 10.2147/RMHP.S291584. eCollection 2021.

Fauquier blog
Fauquier ENT

Dr. Christopher Chang is a private practice otolaryngology, head & neck surgeon specializing in the treatment of problems related to the ear, nose, and throat. Located in Warrenton, VA about 45 minutes west of Washington DC, he also provides inhalant allergy testing/treatment, hearing tests, and dispenses hearing aids.

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