DOI record: { "DOI": "10.25258/ijddt.16.46s.21", "ISSN": [ "0975-4415" ], "URL": "http://dx.doi.org/10.25258/ijddt.16.46s.21", "abstract": "<jats:p>Background. Povidone–iodine (PVP–I) gargles were widely recommended as an oropharyngeal antiseptic measure\nduring the COVID-19 pandemic on the basis of in vitro virucidal activity against SARS-CoV-2. Repeated oral exposure\nto iodine-containing solutions raises theoretical concerns regarding systemic iodine absorption and thyroid homeostasis,\nincluding the Wolff–Chaikoff inhibitory effect and iodine-induced thyrotoxicosis. Empirical data on thyroid biochemistry\nduring short-term, low-concentration PVP–I gargling in adults concurrently infected with SARS-CoV-2 are limited.\nObjectives. To describe changes in serum free triiodothyronine (fT3), total thyroxine (TT4), and thyroid-stimulating\nhormone (TSH) in young euthyroid adults with asymptomatic SARS-CoV-2 infection during a standardised regimen of\nshort-term, low-concentration PVP–I gargling, without inferring causality.\nMethods. In this single-arm, single-centre, prospective cohort study conducted at a tertiary care hospital in Leh, Ladakh\n(April–May 2020), 45 inpatients aged 20–35 years with reverse transcription polymerase chain reaction (RT-PCR)–\nconfirmed, clinically asymptomatic SARS-CoV-2 infection and a normal baseline thyroid profile gargled once daily with\n15 mL of 0.33% PVP–I solution (approximately 5 mg of available iodine per gargle) for 30 seconds at bedtime under\ndirect nursing observation. Gargling continued until the first negative SARS-CoV-2 RT-PCR (10–15 days). Serum fT3,\nTT4, and TSH were measured at enrolment (Time A) and at first negative RT-PCR (Time B) on a single\nelectrochemiluminescence immunoassay platform; paired samples from each participant were stored at −20 °C and\nprocessed in the same analytical run. Distributional normality was assessed by the Shapiro–Wilk test; paired comparisons\nused the paired t-test with Wilcoxon signed-rank as a sensitivity analysis. Standardised within-subject effect sizes\n(Cohen's dz) and Bonferroni-adjusted p-values were reported. A pre-specified sensitivity analysis stratified participants\nby exposure duration (≤ 12 vs &gt; 12 days).\nResults. Mean serum fT3 rose from 3.21 ± 0.46 pg/mL at Time A to 3.30 ± 0.45 pg/mL at Time B (mean change Time B\n− Time A = +0.09 pg/mL; 95% CI 0.073 to 0.105; dz = 1.80; p &lt; 0.001; Bonferroni-adjusted p &lt; 0.003). Mean serum TT4\nrose from 7.97 ± 1.63 to 8.02 ± 1.62 µg/dL (mean change +0.05 µg/dL; 95% CI 0.020 to 0.074; dz = 0.56; adjusted p =\n0.003). Serum TSH did not change significantly (2.54 ± 0.88 vs. 2.60 ± 1.19 µIU/mL; mean change +0.06 µIU/mL; 95%\nCI −0.27 to 0.38; dz = 0.06; p = 0.721). All thyroid parameters remained within laboratory reference ranges, and no\nparticipant developed clinical thyroid dysfunction or local adverse effects. The observed directional pattern — a small\nrise in fT3 and TT4 with stable TSH — is not the suppressive signature classically predicted under an acute iodine load,\nand is compatible with non-iodine influences including recovery from low-T3 non-thyroidal illness syndrome during\nclearance of acute SARS-CoV-2 infection.\nConclusion. In this single-arm cohort without a non-exposed comparator, thyroid hormone trajectories during short-term,\nlow-concentration PVP–I gargling in young euthyroid adults with asymptomatic SARS-CoV-2 infection remained within\nthe laboratory reference range and showed no biochemical signature of acute iodine-induced thyroid inhibition. These\nfindings are compatible with — but cannot prove — the short-term thyroid safety of dilute PVP–I gargling; controlled\nstudies incorporating urinary iodine quantification and a non-exposed comparator are required for causal attribution.</jats:p>", "author": [ { "affiliation": [ { "name": "Department of Anaesthesiology, Critical Care and Emergency Medicine, Base Hospital Delhi Cantonment, Delhi, India" } ], "family": "Singh", "given": "Jung Bahadur", "role": [ { "role": "author", "vocabulary": "crossref" } ], "sequence": "first" }, { "affiliation": [ { "name": "Department of Anaesthesiology, Critical Care and Emergency Medicine, Base Hospital Delhi Cantonment, Delhi, India" } ], "family": "Sasidharan", "given": "Shibu", "role": [ { "role": "author", "vocabulary": "crossref" } ], "sequence": "additional" }, { "affiliation": [ { "name": "Department of Anaesthesiology, Critical Care and Emergency Medicine, Base Hospital Delhi Cantonment, Delhi, India" } ], "family": "Sharma", "given": "Manoj Kumar", "role": [ { "role": "author", "vocabulary": "crossref" } ], "sequence": "additional" }, { "affiliation": [ { "name": "Specialist Community Medicine, Military Hospital, Jammu" } ], "family": "R", "given": "Vishnuprasad", "role": [ { "role": "author", "vocabulary": "crossref" } ], "sequence": "additional" } ], "container-title": "International Journal of Drug Delivery Technology", "container-title-short": "IJDDT", "content-domain": { "crossmark-restriction": false, "domain": [] }, "created": { "date-parts": [ [ 2026, 6, 4 ] ], "date-time": "2026-06-04T09:32:16Z", "timestamp": 1780565536000 }, "deposited": { "date-parts": [ [ 2026, 6, 4 ] ], "date-time": "2026-06-04T09:32:17Z", "timestamp": 1780565537000 }, "indexed": { "date-parts": [ [ 2026, 6, 4 ] ], "date-time": "2026-06-04T10:04:33Z", "timestamp": 1780567473573, "version": "3.54.1" }, "is-referenced-by-count": 0, "issue": "46s", "issued": { "date-parts": [ [ 2026, 6, 4 ] ] }, "journal-issue": { "issue": "46s", "published-online": { "date-parts": [ [ 2026, 6, 4 ] ] } }, "link": [ { "URL": "https://impactfactor.org/PDF/IJDDT/16/IJDDT,Vol16,Issue46s,Article21.pdf", "content-type": "unspecified", "content-version": "vor", "intended-application": "similarity-checking" } ], "member": "10897", "original-title": [], "prefix": "10.25258", "published": { "date-parts": [ [ 2026, 6, 4 ] ] }, "published-online": { "date-parts": [ [ 2026, 6, 4 ] ] }, "publisher": "Dr. Yashwant Research Labs Pvt. Ltd.", "reference-count": 0, "references-count": 0, "relation": {}, "resource": { "primary": { "URL": "https://impactfactor.org/PDF/IJDDT/16/IJDDT,Vol16,Issue46s,Article21.pdf" } }, "score": 1, "short-title": [], "source": "Crossref", "subject": [], "subtitle": [], "title": "Changes in Thyroid Function Parameters during Short-Term LowConcentration Povidone–Iodine Gargling in Young Adults with Asymptomatic SARS-CoV-2 Infection: A Single-Arm Prospective Cohort Study", "type": "journal-article", "volume": "16" }