Saline nasal irrigation and gargling in COVID-19: Part II. Outcomes in Omicron and risk-benefit for selfcare

Suzy Huijghebaert^1*Cristoforo Fabbris^2,3Amy L. Baxter⁴Shehzad Parviz⁵UDAY SANKAR CHATTERJEE⁶David Rabago⁷

• ¹ORCID-ID 0000-0002-5477-6838, Independent researcher, Antwerp, Belgium
• ²2. ENT Unit, Department of Surgery, Ospedali Riuniti Padova Sud, 35043 Monselice-Padova, Italy
• ³3. Department of Medicine DIMED, Padova University, 35100 Padova, Italy
• ⁴Department of Emergency Medicine, 1120 15th Street, Augusta, GA 30912, United States
• ⁵5. Infectious Diseases, Geriatrics & Post Acute Care, Bethesda, United States
• ⁶Department of Paediatric Surgery, Park Medical Research and Welfare Society,, Kolkata, West Bengal, India
• ⁷Department of Family and Community Medicine, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States

The WHO recommends at-home management of mild COVID-19. While a preliminary evaluation provided evidence for saline nasal irrigation (SNI) and gargling in COVID-19, an update and risk-benefit assessment for selfcare in Omicron infection is warranted, from treatment and preparedness perspectives, as new SARS-CoV-2 variants continuously emerge, while symptoms overlap with those of common colds and other upper respiratory tract infections. Methods: Systematic literature searches for preclinical and clinical studies involving Omicron infection and saline, bias assessment, review of outcomes (benefits, risks). Results. Fourteen studies met eligibility criteria: 1 experimental proof-of-concept study, 8 randomized clinical trials (RCTs), 2 quasi-experimental, 2 matched case-control and 1 controlled study (2389 patients, 1101 receiving saline). Study designs were highly heterogeneous, not allowing pooling of the data. In line with the pre-clinical findings, the clinical trials showed lower viral loads or faster viral clearance; results were consistent, if SNI was started early in the infection. Individual studies supported reduced infectivity of saliva, inflammatory mediators and C-reactive protein, and increased lymphocytes. Symptoms resolved faster if severe at baseline, in line with the findings from pre-Omicron RCTs; the ability to perform daily activities was assessed in one RCT and improved significantly. Early initiation of daily SNI/gargling before onset of smell/taste dysfunction prevented their development. Daily SNI hygiene was also associated with less frequent development of fever and a shorter duration of fever than observed among (non-irrigating) controls. Daily SNI modestly helped to reduce household transmission; a preliminary report suggests that reliable prophylaxis can be achieved provided daily SNI is combined with strict use of personal protective measures. Hospitalization was virtually absent. Isotonic SNI was best tolerated. Conclusions. This analysis confirms prior review findings: early initiation of SNI/gargling may help patients with mild COVID-19 feel better, irrespective of the variant. Provided clean water and irrigation materials are used, SNI can reasonably be recommended as early selfcare for COVID-19, as it is for the common cold. Larger prospective studies are required for optimized protocols and SNI's potential role in respiratory pathogen pandemic preparedness.