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Background & objectives: In the present scenario, the most common sample for diagnosis of COVID-19 by reverse transcription polymerase chain reaction (RT-PCR) is nasal and throat swab (NTS). Other sampling options such as gargle lavage have found limited application in clinical use mostly because of unavailability of an appropriate gargling liquid. This study was conducted to assess the stability of SARS-CoV-2 RNA in normal saline at 4°C that can serve as a gargling liquid as well as a transport medium. The study also looked at the agreement between NTS and gargle lavage/saliva for the detection of SARS-CoV-2. Methods: In 29 consecutive real-time RT-PCR (rRT-PCR) positive COVID-19 patients, paired NTS, gargle and saliva samples were taken. Samples were processed by rRT-PCR for the detection of SARS-CoV-2 RNA. To assess the SARS-CoV-2 RNA stability in normal saline, gargle lavage specimens were divided into two aliquots; one subset of the specimen was run within 4-6 h along with the routine samples (NTS and saliva) and the other subset was stored at 4°C and processed after 24-30 h. Agreement between cycle threshold (Ct) values from both the runs was compared using Bland–Altman (BA) analysis. Results: The positivity rates of rRT-PCR in NTS, saliva and gargle lavage samples were 82.7 (24/29), 79.3 (23/29) and 86.2 per cent (25/29), respectively. BA plot showed a good agreement between the Ct values of fresh and stored gargle samples, stipulating that there were no significant differences in the approximate viral load levels between the fresh and stored gargle lavage samples (bias: E gene −0.64, N gene −0.51, ORF gene −0.19). Interpretation & conclusions: Our study results show stability of SARS-CoV-2 RNA in the gargle samples collected using normal saline up to 24-30 h. Gargle lavage and saliva specimen collection are cost-effective and acceptable methods of sampling for the detection of SARS-CoV-2 RNA by rRT-PCR. These simplified, inexpensive and acceptable methods of specimen collection would reduce the cost and workload on healthcare workers for sample collection.

Background & objectives: Coronavirus disease 2019 (COVID-19) has so far affected over 41 million people globally. The limited supply of real-time reverse transcription-polymerase chain reaction (rRT-PCR) kits and reagents has made meeting the rising demand for increased testing incompetent, worldwide. A highly sensitive and specific antigen-based rapid diagnostic test (RDT) is the need of the hour. The objective of this study was to evaluate the performance of a rapid chromatographic immunoassay-based test (index test) compared with a clinical reference standard (rRT-PCR). Methods: A cross-sectional, single-blinded study was conducted at a tertiary care teaching hospital in north India. Paired samples were taken for RDT and rRT-PCR (reference standard) from consecutive participants screened for COVID-19 to calculate the sensitivity and specificity of the RDT. Further subgroup analysis was done based on the duration of illness and cycle threshold values. Cohen's kappa coefficient was used to measure the level of agreement between the two tests. Results: Of the 330 participants, 77 were rRT-PCR positive for SARS-CoV-2. Sixty four of these patients also tested positive for SARS-CoV-2 by RDT. The overall sensitivity and specificity were 81.8 and 99.6 per cent, respectively. The sensitivity of RDT was higher (85.9%) in participants with a duration of illness ≤5 days. Interpretation & conclusions: With an excellent specificity and moderate sensitivity, this RDT may be used to rule in COVID-19 in patients with a duration of illness ≤5 days. Large-scale testing based on this RDT across the country would result in quick detection, isolation and treatment of COVID-19 patients.

Background & objectives: Chloroquine (CQN) administered as nasal drops has the potential to achieve much greater local tissue levels than with oral/systemic administration. This trial was undertaken to study the efficacy and safety profile of topical nasal administration of CQN drops in reducing viral load and preventing clinical progression in early COVID-19 infection. Methods: This randomized clinical trial was done with a sample size of 60. Reverse transcription-polymerase chain reaction (RT-PCR) confirmed asymptomatic patients or those with mild COVID-19 illness [National Early Warning Score (NEWS) ≤4] were included. Patients were randomized in a 1:1 manner. Control arm (standard supportive treatment, n=30) was compared with intervention arm (n=30) of standard treatment plus CQN eye drops (0.03%) repurposed as nasal drops administered six times daily (0.5 ml/dose) for 10 days. Outcome measures were adverse events and adherence; clinical progression and outcomes were measured by NEWS; sequential RT-PCR cycle threshold (Ct) values were also noted on days 0, 3, 7 and 10. Results: Nasal CQN was associated with local irritation in seven and non-compliance in one of 30 patients. Eleven patients were excluded due to enrolment error (2 – recovered; 9 – false-positive referral), and 49 patients were analyzed as per modified intention-to-treat analysis. Clinical recovery was noted as similar with 100 per cent asymptomatic by day seven in both arms. Virological outcomes also indicated similarly improving Ct values in both arms, and similar proportion of patients transitioning to non-infectivity by day 10 (controls - 19/25; nasal CQN - 15/24). Nine false-positive patients with enrolment error and day 0 RT-PCR negative were initially uninfected but had continuing COVID-19 exposure and treatment as per randomization. Patients receiving nasal CQN (n=5) demonstrated stable Ct values from day 0 to 10, while patients with no nasal CQN (n=4) demonstrated significant dip in Ct value indicating to infection (Ct