Upper respiratory tract infections (URTIs) are most often caused by viruses,¹ which enter the respiratory tract through inhalation of aerosols produced during coughing, sneezing, singing or even talking. Viral URTIs are usually self-limiting, but in some patients, secondary bacterial infections such as pneumonia may occur, which increase the severity and duration of the disease. Coinfections can also occur. ^2,3  The elderly and the immunocompromised are particularly at risk of developing bacterial infections. Prognosis is poor in these patients. Clinical clues suggestive of secondary bacterial infection include high grade fever >101°F, persistence of symptoms for longer than the expected duration for a viral infection, productive cough with green-yellow sputum.

The probable mechanisms for secondary bacterial infections are ciliary dysfunction causing decreased mucociliary clearance and reduced immunity. Additionally, the damaged respiratory epithelium favors opportunistic attachment of bacteria and biofilm formation.^4,5

The inappropriate use of antibiotics to prevent bacterial infections in patients with viral URIs adds to the escalating problem of antibiotic resistance. Hence, there is a need for a therapeutic strategy that would act complementary to other nonpharmacological interventions such as masking, hand washing to prevent the spread of respiratory pathogens.⁶ Gargling, a commonly practiced oral hygiene method, has been shown to be effective in URIs. Since lower respiratory tract infections (LRTIs) are usually preceded by URTIs, gargling can be a useful measure to prevent or reduce occurrence of secondary bacterial complications such as LRTIs. ⁷ Antiseptic mouthwashes/gargles reduce formation of oral biofilm and decrease the oral microbial load thereby preventing development of complications.

Povidone iodine is a widely used antiseptic and has the broadest spectrum of antimicrobial action covering Gram-positive and Gram-negative bacteria, viruses, fungi, protozoa, and bacterial spores compared with other common antiseptics such as chlorhexidine, octenidine, polyhexanide and hexetidine.⁶ It has also demonstrated viricidal activity against several respiratory viruses including the severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses and also the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).⁸ PVP-I gargle/mouthwash has shown rapid and effective bactericidal activity against Klebsiella pneumoniae and Streptococcus pneumoniae.⁹ The other advantages of PVP-I are its faster onset of action, more persistent effect and low potential for resistance. ^6,10

Gargling with PVP-I has been shown to prevent common cold and influenza. ¹¹ It has also been used for the prevention and treatment of sore throats, ¹² which is also now the predominant early symptom of Covid-19, with fever, anosmia becoming less common. Throat being the major site for the replication of Covid-19, gargling can help to reduce the viral load.

Compared with other commonly used gargled antiseptics, gargled PVP-I is well tolerated. ¹²

Handwashing, physical distancing and masking are recommended as preventive measures against SARS-CoV-2. They also protect against other respiratory infections. Gargling with an antiseptic such as PVP-I is complementary to these non-pharmacological interventions. By reducing the viral load, gargling not only prevents person to person transmission of the virus, it also prevents complications such as pneumonia and reduces morbidity and mortality.

References

1. Teng CL, et al. The management of upper respiratory tract infections. Med J Malaysia. 2001;56(2):260-6; quiz 26.
2. Lingard H, et al. Bacterial superinfection in upper respiratory tract infections estimated by increases in CRP values: a diagnostic follow-up in primary care. Scand J Prim Health Care. 2008;26(4):211-5.
3. Manohar P, et al. Secondary bacterial infections in patients with viral pneumonia. Front Med (Lausanne). 2020 Aug 5;7:420.
4. Juan Carlos Cataño-Correa, et al. Bacterial superinfection in adults with COVID-19 hospitalized in two clinics in Medellín-Colombia, 2020. PLoS One. 2021;16(7):e0254671.
5. Hament JM, et al. Respiratory viral infection predisposing for bacterial disease: a concise review. FEMS Immunol Med Microbiol. 1999;26(3-4):189-95.
6. Kanagalingam J, et al. Practical use of povidone‐iodine antiseptic in the maintenance of oral health and in the prevention and treatment of common oropharyngeal infections.Int J Clin Pract. 2015;69:1247–56.
7. Ahmad L. Impact of gargling on respiratory infections. All Life. 2021;14(1):147-58.
8. Anderson DE, et al. Povidone-iodine demonstrates rapid in vitro virucidal activity against SARS-CoV-2, the virus causing COVID-19 disease. Infect Dis Ther. 2020:1–7.
9. Eggers M, et al. In vitro bactericidal and virucidal efficacy of povidone-iodine gargle/mouthwash against respiratory and oral tract pathogens. Infect Dis Ther. 2018;7(2):249–59.
10. Lachapelle JM, et al: Antiseptics in the era of bacterial resistance: a focus on povidone iodine. Clin Pract. 2013;10:579-92.
11. Shiraishi T, et al. Evaluation of the bactericidal activity of povidone-iodine and commercially available gargle preparations. Dermatology. 2002;204 Suppl 1:37-41.
12. Negi N, et al. Povidone-iodine: “The first line of defense” with potential anti-severe acute respiratory syndrome coronavirus-2 efficacy. Int J Oral Health Sci. 2020;10:74-8.