Pharmacokinetic-based failure of a detergent virucidal for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) nasal infections: A preclinical study and randomized controlled trial

Washing Illness Away: A Systematic Review of the Impact of Nasal Irrigation and Spray on COVID-19

OBJECTIVE

Nasal irrigation is a common treatment for sinonasal disorders; however, it is unknown if it can reduce SARS-CoV-2 nasopharyngeal viral load (NVL). This systematic review investigated the efficacy of nasal irrigation with saline, povidone iodine (PVP-I), and intranasal corticosteroids (INCS) at reducing SARS-CoV-2 NVL and transmissibility.

DATA SOURCES

Databases including Embase, MEDLINE, Web of Science, and ClinicalTrials.gov.

REVIEW METHODS

A systematic review was completed with pre-defined search criteria using keywords related to nasal irrigation and COVID-19 from 1946 through January 2024. This review followed PRISMA reporting guidelines and was registered on PROSPERO. Only in-vivo studies testing nasal irrigation with either saline, PVP-I, or INCS for reducing NVL were included.

RESULTS

Nine out of ten studies on saline-based solutions reported positive effects in reducing NVL, with benefits noted in earlier time to negative nasopharyngeal PCR and a greater decline in NVL during early study time points, compared with controls. Isotonic and hypertonic saline mediums were found to be effective with three studies demonstrating enhanced efficacy with additives. Four out of seven studies on PVP-I showed a positive effect on reducing NVL, but results were heterogenous. Four studies demonstrated reduction of transmission with saline or PVP-I. No studies were found on INCS.

CONCLUSION

Saline nasal irrigation showed the best efficacy in reducing SARS-CoV-2 NVL. Additives to saline may have a clinical benefit, but further studies are needed to elucidate their isolated impacts on NVL. Data on PVP-I is inconclusive and further studies are warranted to determine the ideal concentration for irrigation. Laryngoscope, 2024.

Rapid initiation of nasal saline irrigation to reduce severity in high-risk COVID+ outpatients

OBJECTIVE

To determine whether initiating saline nasal irrigation after COVID-19 diagnosis reduces hospitalization and death in high-risk outpatients compared with observational controls, and if irrigant composition impacts severity.

METHODS

Participants 55 and older were enrolled within 24 hours of a + PCR COVID-19 test between September 24 and December 21, 2020. Among 826 screened, 79 participants were enrolled and randomly assigned to add 2.5 mL povidone-iodine 10% or 2.5 mL sodium bicarbonate to 240 mL of isotonic nasal irrigation twice daily for 14 days. The primary outcome was hospitalization or death from COVID-19 within 28 days of enrollment by daily self-report confirmed with phone calls and hospital records, compared to the CDC Surveillance Dataset covering the same time. Secondary outcomes compared symptom resolution by irrigant additive.

RESULTS

Seventy-nine high-risk participants were enrolled (mean [SD] age, 64 [8] years; 36 [46%] women; 71% Non-Hispanic White), with mean BMI 30.3. Analyzed by intention-to-treat, by day 28, COVID-19 symptoms resulted in one ED visit and no hospitalizations in 42 irrigating with alkalinization, one hospitalization of 37 in the povidone-iodine group, (1.27%) and no deaths. Of nearly three million CDC cases, 9.47% were known to be hospitalized, with an additional 1.5% mortality in those without hospitalization data. Age, sex, and percentage with pre-existing conditions did not significantly differ by exact binomial test from the CDC dataset, while reported race and hospitalization rate did. The total risk of hospitalization or death (11%) was 8.57 times that of enrolled nasal irrigation participants (SE = 2.74; P = .006). Sixty-two participants completed daily surveys (78%), averaging 1.8 irrigations/day. Eleven reported irrigation-related complaints and four discontinued use. Symptom resolution was more likely for those reporting twice daily irrigation (X2 = 8.728, P = .0031) regardless of additive.

CONCLUSION

SARS-CoV-2+ participants initiating nasal irrigation were over 8 times less likely to be hospitalized than the national rate.

Saline nasal irrigation and gargling in COVID-19: a multidisciplinary review of effects on viral load, mucosal dynamics, and patient outcomes

With unrelenting SARS-CoV-2 variants, additional COVID-19 mitigation strategies are needed. Oral and nasal saline irrigation (SI) is a traditional approach for respiratory infections/diseases. As a multidisciplinary network with expertise/experience with saline, we conducted a narrative review to examine mechanisms of action and clinical outcomes associated with nasal SI, gargling, spray, or nebulization in COVID-19. SI was found to reduce SARS-CoV-2 nasopharyngeal loads and hasten viral clearance. Other mechanisms may involve inhibition of viral replication, bioaerosol reduction, improved mucociliary clearance, modulation of ENaC, and neutrophil responses. Prophylaxis was documented adjunctive to personal protective equipment. COVID-19 patients experienced significant symptom relief, while overall data suggest lower hospitalization risk. We found no harm and hence recommend SI use, as safe, inexpensive, and easy-to-use hygiene measure, complementary to hand washing or mask-wearing. In view of mainly small studies, large well-controlled or surveillance studies can help to further validate the outcomes and to implement its use.

Upper respiratory tract microbiota dynamics following COVID-19 in adults

To date, little is known about the effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the coronavirus disease 2019 (COVID-19) pandemic, on the upper respiratory tract (URT) microbiota over time. To fill this knowledge gap, we used 16S ribosomal RNA gene sequencing to characterize the URT microbiota in 48 adults, including (1) 24 participants with mild-to-moderate COVID-19 who had serial mid-turbinate swabs collected up to 21 days after enrolment and (2) 24 asymptomatic, uninfected controls who had mid-turbinate swabs collected at enrolment only. To compare the URT microbiota between groups in a comprehensive manner, different types of statistical analyses that are frequently employed in microbial ecology were used, including ⍺-diversity, β-diversity and differential abundance analyses. Final statistical models included age, sex and the presence of at least one comorbidity as covariates. The median age of all participants was 34.00 (interquartile range=28.75-46.50) years. In comparison to samples from controls, those from participants with COVID-19 had a lower observed species index at day 21 (linear regression coefficient=-13.30; 95 % CI=-21.72 to -4.88; q=0.02). In addition, the Jaccard index was significantly different between samples from participants with COVID-19 and those from controls at all study time points (PERMANOVA q<0.05 for all comparisons). The abundance of three amplicon sequence variants (ASVs) (one Corynebacterium ASV, Frederiksenia canicola, and one Lactobacillus ASV) were decreased in samples from participants with COVID-19 at all seven study time points, whereas the abundance of one ASV (from the family Neisseriaceae) was increased in samples from participants with COVID-19 at five (71.43 %) of the seven study time points. Our results suggest that mild-to-moderate COVID-19 can lead to alterations of the URT microbiota that persist for several weeks after the initial infection.