SARS-Cov-2 (COVID-19) Nasal Pharyngeal and Oral Pharyngeal Wash (SNOW) Trial (SNOW)
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ClinicalTrials.gov Identifier: NCT04802408 |
Recruitment Status :
Recruiting
First Posted : March 17, 2021
Last Update Posted : August 26, 2022
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Condition or disease | Intervention/treatment | Phase |
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Covid19 SARS-CoV Infection | Combination Product: Shampoo and saline Combination Product: Saline and Listerine Combination Product: Shampoo and Listerine Combination Product: Saline and Saline | Phase 2 Phase 3 |
Investigators have demonstrated the in vitro viridical efficacy of both Listerine Antiseptic® and 1% dilute baby shampoo solution, a commonly used nasal rinse, against a SARS-CoV-2 surrogate and Meister et al. have similar findings with SARS-CoV-2. With an urgent need to expand the armamentarium of widely available, low-cost interventions, that are safe for repeated human use and reduce viral transmission, investigators seek to determine the impact of a combined regimen of oral and nasal rinsing with these agents on naso-oropharyngeal viral loads in adults (aged 18-65 years) with SARS-CoV-2 infection.
Rationale for the intervention: a combination of nasal washes with 1% solution of baby shampoo and oral washes with Listerine Antiseptic® Available data indicate that SARS-CoV-2 is most likely to spread, like most other common respiratory viruses, primarily through respiratory droplet transmission. With the naso-oropharynx being both the primary site from which the virus is expelled by people with infection and the nasal and oral mucosal cells is one of the sites of initial infection and viral replication. Specifically the ACE2 receptor, that SARS-CoV-2 binds for cell entry, are highly concentrated in the goblet and ciliated cells of the nose and on the tongue. Thus a reduction of viral load through topical treatment of these sites could potentially lead to reduced transmission of SARS-CoV-2.
Each of the two proposed agents to be tested have independently demonstrated virucidal activity with short contact time in vitro. With over 140 years of usage worldwide, the safety of gargles with Listerine Antiseptic® is well established. Topical nasal lavage using a dilute solution of baby shampoo has also been demonstrated to be safe and effective both as a mucoactive and microbicidal agent. Both agents are readily available and cost-efficient for daily usage.
While there are a number of ongoing trials of interventions with similar approaches, most of them focus on a single intervention, either nasal or oral rinses. This potentially leaves a viral reservoir in the untreated site, with the potential for recolonizing the entire oronasopharynx thereby limiting the utility of intervention. There is a single trial treating both the oral and nasal spaces. However, the agent being tested is povidone-iodine, that has known adverse effects limiting its use. These adverse effects include discoloration of teeth, ciliary dysfunction, iodine overdose and possible drug interactions, such as with lithium.
Investigators believe that the proposed intervention for this study is likely to be well-tolerated, highly acceptable and result in elimination from the key sites in the oronasopharynx. Additionally, the proposed four-arm design will allow investigators to compare the combined intervention with each of the component treatments. A decision was made to use saline rinses as the control arm as the investigator's in vitro data revealed that saline had no virucidal activity against human coronavirus.
Based on recent literature describing viral load dynamics during the course of SARS-CoV-2 infection, investigators believe that a four-day trial, initiated within 5 days of Covid testing, will allow for the testing of change in viral load close to/or within the 7-10 day timeframe of greatest SARS-CoV-2 viral load. The study period will also fall within the 2-3 week period of the mean duration of SARS-CoV-2. Mohamed et al suggest that 4 days of oral Listerine washes three times daily may be efficacious in decreasing viral load. Several other rinse trials also employ this rinse frequency. The rinse times of 60 secs and 30 secs for nasal wash with 1% dilute baby shampoo and oral Listerine respectively, are based on the successful virus reduction demonstrated at these contact times in vitro.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 200 participants |
Allocation: | Randomized |
Intervention Model: | Factorial Assignment |
Intervention Model Description: | This is a prospective, randomized, controlled, 2x2 factorial, phase 2/phase 3 trial to compare the impact of a 4-day intervention of nasal washes with 1% baby shampoo solution and/or oropharyngeal gargles with Listerine Antiseptic® solution compared to that of nasal washes with buffered saline solution and/or oropharyngeal rinses with saline solution on naso-oropharyngeal SARS-CoV-2 viral load in a population of adults (aged 18-65 years) with SARS-CoV-2 infection diagnosed within 5 days who are asymptomatic or mildly symptomatic for COVID-19 disease. |
Masking: | Single (Outcomes Assessor) |
Masking Description: | We plan to provide the number and proportion of the primary outcome of participants who have completed 5 days of follow up from randomization, by treatment arms to an independent biostatistician, as well as participant accrual rate, and withdrawals from study. A formal interim analysis (as detailed in the analysis section) will be completed when 67% of final sample size reaches day 5 and the results will be provided masked to the independent biostatistician, who will decide whether to halt the trial or not. |
Primary Purpose: | Treatment |
Official Title: | SARS-Cov-2 (COVID-19) Nasal Pharyngeal and Oral Pharyngeal Wash (SNOW) Trial |
Actual Study Start Date : | October 1, 2021 |
Estimated Primary Completion Date : | May 30, 2023 |
Estimated Study Completion Date : | May 30, 2023 |

Arm | Intervention/treatment |
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Active Comparator: Baby Shampoo Nasal Wash
Nasal washes with 1% baby shampoo solution and oropharyngeal gargles with saline solution
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Combination Product: Shampoo and saline
Nasal washes with 1% baby shampoo solution and oropharyngeal gargles with saline solution |
Active Comparator: Listerine Gargle
Nasal washes with buffered saline solution and oropharyngeal gargles with Listerine Antiseptic® solution
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Combination Product: Saline and Listerine
Nasal washes with buffered saline solution and oropharyngeal gargles with Listerine Antiseptic® solution |
Experimental: Combination of Baby Shampoo Nasal Wash and Listerine Gargle
Nasal washes with 1% baby shampoo solution and oropharyngeal gargles with Listerine Antiseptic® solution
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Combination Product: Shampoo and Listerine
Nasal washes with 1% baby shampoo solution and oropharyngeal gargles with Listerine Antiseptic® solution |
Placebo Comparator: Saline Wash and Gargles
Nasal washes with buffered saline solution and oropharyngeal gargles with saline solution
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Combination Product: Saline and Saline
Nasal washes with buffered saline solution and oropharyngeal gargles with saline solution |
- Viral Load Change from baseline [ Time Frame: 5 days ]Primary Study Endpoints The primary endpoint is the change from baseline in measured viral load in the nose and mouth of adults aged 18-65 years with SARS-CoV-2 infection after 4 days of washes (Day 5 vs Day 1). This will be measured using quantitative PCR (qPCR) analysis, with standard procedures to make cDNA copies of the viral genomic RNA and using CDC recommended primers qPCR to determine viral load. Four separate regimens will be evaluated: 1% dilute baby shampoo nasal wash and a saline oral gargle; buffered saline nasal wash and Listerine oral gargle; 1% dilute baby shampoo nasal wash and Listerine oral gargle; and buffered saline nasal wash and saline oral gargle.
- 4-day trend in viral load change [ Time Frame: 5 days ]The 4-day trend in viral load change in the nose and mouth of adults with SARS-CoV-2 infection measured with qPCR each morning on Days 1, 2, 3 and 4, as well as the post-intervention level measured on Day 5.
- Levels of live virus (viral infectivity titer) [ Time Frame: 15 minutes ]The change in measured levels of live virus (viral infectivity titer), detected from the nose and mouth after the first wash on the morning of Day 1 compared to live virus detected before the first wash on Day 1 (baseline) . Infectivity will be measured by the number of plaque forming units in Vero cells
- Levels of live virus (viral infectivity titer) [ Time Frame: 1 day ]The change in measured levels of live virus (viral infectivity titer) detected from the nose and mouth 24 hours after the initiation of rinses on Day 1. Infectivity will be measured by the number of plaque forming units in Vero cells
- The tolerability of the intervention measured using the validated Sino-nasal outcome test (SNOT-22) scale. [ Time Frame: 5 days ]
The tolerability of the intervention measured using the validated Sino-nasal outcome test (SNOT-22) scale.
The minimum score is 0 and the maximum score is 110, where a higher score is less tolerable.
- Compliance as measured by percent of expected washes completed [ Time Frame: 5 days ]Participant compliance to the intervention will be calculated by percent of expected washes completed.
- Compliance as measured by percentage of randomized participants that withdrew consent and elected not to continue in the study. [ Time Frame: 5 days ]Compliance will be measured by determining the percentage of randomized participants that withdrew consent and elected not to continue in the study.
- Acceptability of the intervention as measured by 7 item questionnaire based an acceptability framework described by Sekhon (2017) [ Time Frame: 6 days ]The acceptability of the intervention, using a structured 7 item questionnaire based on the acceptability framework described by Sekhon (2017). The minimum score is 7 and the maximum score is 35. With the higher score being more acceptible.

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Ages Eligible for Study: | 18 Years to 65 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- A first-time positive test for SARS-CoV-2 infection within 5 days of enrollment
- Adults who are ≥18 -65 years of age
- Currently in isolation
- Symptomatic or asymptomatic from SARS-CoV-2
Exclusion Criteria:
- History of nasal or sinus surgery
- Non-English speaking
- Lack of electronic device (computer, mobile phone etc.) on which to access an app for study data collection.
- Adults that need inpatient care for COVID-19 or any of its complications.
- Adults that give a history of being unable to tolerate gargles or nasal washes.
- Adults who do not give informed consent for study participation.
- History of a Covid vaccine booster
- A history of use of nasal or oral washes after SARS-CoV-2 test sample collection.
- Prisoners
- Adults that give history of current pregnancy (NO KNOWN CONTRAINDICATION TO PREGNANCY)
- History of monoclonal antibody treatment
- History of or current molnupiravir treatment

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04802408
Contact: Rena Kass, MD | 717-531-8815 | rkass@pennstatehealth.psu.edu | |
Contact: Omrana Pasha-Razzak, MD | 717-531-1826 | opasha@pennstatehealth.psu.edu |
United States, Pennsylvania | |
Penn State Health Milton S. Hershey Medical Center | Not yet recruiting |
Hershey, Pennsylvania, United States, 17033 | |
Contact: Rena Kass, MD 717-531-8815 rkass@pennstatehealth.psu.edu | |
Penn State | Recruiting |
State College, Pennsylvania, United States, 16801 | |
Contact: Deborah Bagshaw, BS 814-865-4302 ddm108@psu.edu |
Principal Investigator: | Rena Kass, MD | Penn State College of Medicine |
Responsible Party: | Rena Kass, Associate Professor, Department of Surgery, Milton S. Hershey Medical Center |
ClinicalTrials.gov Identifier: | NCT04802408 |
Other Study ID Numbers: |
STUDY00016947 |
First Posted: | March 17, 2021 Key Record Dates |
Last Update Posted: | August 26, 2022 |
Last Verified: | August 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Covid 19 SARS-CoV-2 Viral Load Nasal Rinse Oral Rinse |
COVID-19 Severe Acute Respiratory Syndrome Respiratory Tract Infections Infections Pneumonia, Viral Pneumonia Virus Diseases Coronavirus Infections Coronaviridae Infections Nidovirales Infections |
RNA Virus Infections Lung Diseases Respiratory Tract Diseases Listerine Sodium Fluoride Anti-Infective Agents, Local Anti-Infective Agents Cariostatic Agents Protective Agents Physiological Effects of Drugs |