Estimation of conjunctival swab and nasopharyngeal swab specimens for viral nucleic acid detection in Coronavirus disease 2019 patients to compare the viral load

Abstract

Objectives: The purpose of the study was to detect the presence of viral ribonucleic acid of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in conjunctival swab along with nasopharyngeal swab specimens of Coronavirus disease 2019 (COVID-19) patients. Material and Methods: Thirty COVID-19 patients with at least one sample positive for real-time reverse transcription-polymerase chain reaction for SARS-CoV-2 in nasopharyngeal swab with the presence or absence of ocular manifestations were included in the study. The conjunctival swab along with nasopharyngeal swab of each patient was collected and sent to microbiology lab for evaluation and analysis of viral nucleic acid to assess the viral load. Results: Out of 30 patients, 21 patients (70%) were males and the remaining nine patients (30%) were females. Mean age of the patients in the study was 44.80 ± 15.37 years. One patient had conjunctivitis as ocular manifestation. Two (6.7%) out of 30 patients were positive for RT-PCR SARS-CoV-2 in the conjunctival swab. There was no statistical correlation between nasopharyngeal swab and conjunctival swab positivity using Pearson’s correlation coefficient (r) = 0.010; P = 0.995 (>0.05). Conclusion: The results of the study revealed that SARS-CoV-2 can also be detected in conjunctival swabs of confirmed cases of COVID-19 patients. Although, in comparison to nasopharyngeal and throat swabs the rate of detection of SARS-CoV-2 in conjunctival swabs is relatively less, still diligent care and precautions should be practiced during the ophthalmic evaluation of COVID-19 patients.